PREPARATION AND QUALITY EVALUATION OF GINGER WINE

PREPARATION AND QUALITY EVALUATION OF
GINGER WINE
by
Pushpa L. Rai
Central Department of Food Technology
Institute of Science and Technology
Tribhuvan University, Nepal
November, 2009

ii
Preparation and Quality Evaluation of Ginger Wine
A dissertation submitted to the Central Department of Food Technology
in Tribhuvan University in partial fulfillment of the requirements
for the degree of M. Tech. in Food Technology
by
Pushpa L. Rai
Tribhuvan University
Dharan, Hattisar, Nepal
November, 2009

iii
Tribhuvan University
Central Campus of Technology, Dharan
Approval Letter
This dissertation entitled Preparation and Quality Evaluation of Ginger Wine
presented by Pushpa L. Rai has been accepted as the partial fulfillment of the
requirements for the M. Tech. in Food Technology.
Dissertation Commettee
1. Head of Department __________________________
(Assoc. Prof. Dhan B. Karki)
2. External Examiner __________________________
(Prof. Dr. Ganga P. Kharel)
3. Supervisor __________________________
(Assoc. Prof. Dhan B. Karki)
4. Internal Examiner __________________________
(Lecturer Babita Adhikari)
Date: 24th
November, 2009

iv
Acknowledgements
I would like to express my hearty sense of gratitude to Assoc. Prof. Dhan Bahadur Karki,
Chief of Central Department of Food Technology, Hattisar, Dharan. He encouraged me to
carry out this dissertation and provided valuable insights to coordinate the sources of
information and to proceed the research work. I would like to express my gratitude to him
for his moral and technical support with frequent inspiration and supervision.
I extend my profound gratitude to Assoc. Prof. Basanta Rai, CCT, Hattisar, Dharan, for
providing me GenStat software programme. I am also grateful to Mr. Bhaskar Mani
Adhikari , Mr. Ghanendra Gartaula, Mr. Santosh Singh, Mrs. Meera Shrestha, Mr. Madhav
Prasad Tiwari, Mr. Dipesh Basyal for providing me constant support during my
dissertation work. I express my hearty gratitude to Mr. Sujan Shrestha, Manager, Makalu
Wine Industries (P.) Ltd., Basantapur, Tehrtathum, for providing me true wine yeast for
this dissertation.
I would like to express my hearty thanks to my teachers, all friends, and staff of library
and laboratory, for their direct and indirect co-operation, and suggestions. I express my
affectionate thanks to D. Katuwal, Dharan-11, Sunsari, for providing me constant
inspirations.
At last, I owe my deepest gratitude to my respected parents and my family for making me
able to stand in this position where I am now.
________________
Pushpa L. Rai
24th
November, 2009

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Abstract
Effect of mash TSS (16, 20 and 24o
Brix), ginger amount (1, 1.5 and 2% m/v) and yeast
types (Saccharomyces cerevisiae and Saccharomyces ellipsodeus) on the chemical and
sensory qualities of the wines were studied. The wine was clarified using bentonite
suspension (5% m/v). Fermentation mash containing 10% raisin, 20o
Brix TSS, 4.5 pH and
1% ginger (m/v) was found to be optimum for wine fermentation using baker’s yeast (S.
cerevisiae) at room temperature (28-30o
C).
The average pH, TSS (o
Brix), alcohol content (%v/v), total acidity (as g lactic acid/L),
fixed acidity (as g lactic acid/L), volatile acidity (as g lactic acid/L), reducing sugar (g/L),
esters (as mg ethyl acetate/L alcohol) and total aldehydes (mg acetaldehyde/L alcohol) of
the ginger wines fermented by wine and baker’s yeasts were found to be 4.1 and 4.2, 5.8
and 6.2, 7.8 and 8.71, 7.56 and 7.92, 5.4 and 5.88, 2.16 and 2.04, 5 and 6, 45.5 and 40.23
and 30.61 and 23.16 respectively. TSS, total acidity, fixed acidity, volatile acidity, esters
and total aldehydes were not significantly different but pH, alcohol and reducing sugar
were significantly different (p<0.05). Sensory analysis showed that taste and mouth feel
were not significantly different but smell, color and overall acceptance scores were
significantly higher in wine fermented by true wine yeast compared to baker’s yeast.
Bentonite was found to be most effective at the rate of 0.5g/L for the clarification of
ginger wine. The ginger wine could be prepared from the mash having 10% raisin, 20o
Brix
TSS, 1% ginger (m/v) and 4.5pH by using baker’s yeast in comparable quality to that
fermented by true wine yeast.

Contents
Approval Letter ..................................................................................................................iii
Acknowledgements............................................................................................................. iv
Abstract ................................................................................................................................ v
1. Introduction ..................................................................................................................... 1
1.1 General introduction.................................................................................................... 1
1.2 Statement of problem................................................................................................... 2
1.3 Significance of the study ............................................................................................. 2
1.4 Objective of the study.................................................................................................. 3
1.5 Limitations................................................................................................................... 3
2. Literature review............................................................................................................. 4
2.1 Introduction of Ginger................................................................................................. 4
2.2 Varieties of ginger cultivated in Nepal........................................................................ 4
2.3 Composition of ginger................................................................................................. 5
2.4 Ginger and its health benefits...................................................................................... 5
2.5 Historical background of alcoholic beverage.............................................................. 6
2.5.1 Brief description of alcoholic beverages .............................................................. 7
2.5.2 Classification of alcoholic beverages ................................................................... 8
2.6 Traditional alcoholic beverages of Nepal.................................................................. 11
2.6.1 Jand..................................................................................................................... 11
2.6.2 Rakshi................................................................................................................. 11
2.6.3 Toddy/ Tadi ........................................................................................................ 11
2.7 History of wine making............................................................................................. 12
2.8 Classification of wine................................................................................................ 13
2.9 General cultural conditions for fermentation............................................................. 15
2.9.1 pH ....................................................................................................................... 16
2.9.2 Temperature........................................................................................................ 16
2.9.3 Sugar concentration............................................................................................ 16
2.10 Wine yeast ............................................................................................................... 17
2.11 Alcoholic fermentation............................................................................................ 17
2.11.1 Biochemistry of alcohol fermentation .............................................................. 18
2.11.2 Malo-lactic fermentation .................................................................................. 19
2.12 Technology of wine production............................................................................... 19
2.12.1 Selection of raw material.................................................................................. 21
2.12.2 Blending/ Crushing........................................................................................... 21
2.12.3 Sulphiting/ Preservatives.................................................................................. 21
2.12.4 Yeast................................................................................................................. 21
2.12.4.1 Inoculum Development and Pitching ........................................................ 23
2.12.4.2 Fermentation.............................................................................................. 23
2.12.4.3 Factors influencing fermentation............................................................... 25
2.12.4.3.1 Yeast culture....................................................................................... 25
2.12.4.3.2 Sugar and its concentration................................................................. 25
2.12.4.3.3 Sulphur-dioxide .................................................................................. 26
2.12.4.3.4 Acids and pH ...................................................................................... 26
2.12.4.3.5 Temperature........................................................................................ 27
2.12.4.3.6 Minerals and growth factors............................................................... 28
2.12.4.3.7 Oxygen................................................................................................ 28

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2.12.4.3.8 Ethanol toxicity................................................................................... 28
2.12.5 Problems during fermentation .......................................................................... 29
2.12.5.1 Stuck fermentation..................................................................................... 29
2.12.5.2 Production of off-characters...................................................................... 29
2.12.5.3 Methanol production and its quality.......................................................... 30
2.12.5.4 Activity of undesirable microorganisms.................................................... 30
2.13 Racking.................................................................................................................... 30
2.14 Clarification and fining............................................................................................ 31
2.15 Stabilization of wine................................................................................................ 31
2.16 Maturing and aging of wine..................................................................................... 31
2.17 Bottling.................................................................................................................... 32
2.18 Pasteurization........................................................................................................... 32
2.19 Finishing.................................................................................................................. 33
2.20 Storage and ageing of wine ..................................................................................... 33
2.21 Wine made from different raw materials................................................................. 34
2.22 Fining agent and its types........................................................................................ 35
2.22.1 The Proteins...................................................................................................... 35
2.22.2 The Earths......................................................................................................... 36
2.22.2.1 Bentonite and its properties....................................................................... 36
2.22.2.2 Preparation of bentonite............................................................................. 37
2.22.3 Synthetic Polymers........................................................................................... 38
2.22.4 The Colloids ..................................................................................................... 38
2.22.4.1 Natural Polysaccharides ............................................................................ 38
2.22.5 Alternative Methods of Metal Depletion.......................................................... 39
2.22.6 Activated Carbon.............................................................................................. 39
2.22.7 Silica Suspension.............................................................................................. 39
2.23 Components of wine................................................................................................ 40
2.23.1 Ethanol.............................................................................................................. 40
2.23.2 Methanol........................................................................................................... 40
2.23.3 Higher alcohols (Fusel oils).............................................................................. 41
2.23.4 Carbonyl compounds........................................................................................ 41
2.23.5 Esters ................................................................................................................ 42
2.23.6 Acids................................................................................................................. 42
2.23.7 Glycerol ............................................................................................................ 43
2.23.8 Minerals............................................................................................................ 43
2.23.9 Pectins and gums .............................................................................................. 43
2.23.10 Water and sugar.............................................................................................. 44
2.24 Yield ........................................................................................................................ 44
2.25 Wine defects and spoilage....................................................................................... 44
2.26 Wine and its health benefits..................................................................................... 45
2.27 Brief Introduction of Ginger wine........................................................................... 46
3. Materials and methods.................................................................................................. 47
3.1 Raw Materials............................................................................................................ 47
3.2 Optimization of TSS and amount of ginger in the fermentation mash...................... 47
3.2.1 Preparation of mash............................................................................................ 47
3.2.2 Pitching and agitation......................................................................................... 48
3.2.3 Fermentation....................................................................................................... 48
3.2.4 Racking, pasteurization and bottling .................................................................. 48
3.2.5 Quality analysis .................................................................................................. 50

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3.3 Selection of the best yeast ......................................................................................... 50
3.4 Clarification of ginger wine using Bentonite ............................................................ 50
3.5 Analytical methods.................................................................................................... 50
3.6 Quality analysis of prepared wines............................................................................ 51
3.6.1 Sensory evaluation.............................................................................................. 51
3.6.2 Statistical analysis............................................................................................... 51
4. Results and discussion................................................................................................... 52
4.1 Effect of TSS and ginger amount on the chemical and sensory quality of ginger wine
......................................................................................................................................... 52
4.1.1 Effect on chemical characteristics ...................................................................... 52
4.2 Effect of yeast culture on chemical and sensory properties ...................................... 57
4.2.1 pH ....................................................................................................................... 58
4.2.3 Alcohol content................................................................................................... 58
4.2.4 Total acidity........................................................................................................ 59
4.2.6 Volatile acidity ................................................................................................... 60
2.4.7 Reducing sugar ................................................................................................... 60
4.2.8 Esters .................................................................................................................. 61
4.2.9 Total aldehydes................................................................................................... 61
4.3 Sensory Evaluation.................................................................................................... 61
4.3.1 Smell................................................................................................................... 62
4.3.2 Taste.................................................................................................................... 62
4.3.3 Mouth feel........................................................................................................... 62
4.3.4 Color................................................................................................................... 63
4.3.5 Overall acceptance.............................................................................................. 63
4.4 Effect of bentonite on the clarification of ginger wine.............................................. 63
5. Conclusion and recommendation................................................................................. 65
5.1 Conclusions ............................................................................................................... 65
5.2 Recommendations ..................................................................................................... 65
6. Summary ........................................................................................................................ 66
References ........................................................................................................................... 68
Appendices .......................................................................................................................... 74

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List of fables and figures
List of tables
Table2.1 The chemical composition of ginger……………………………………..…5
Table2.2 Classification of distilled and un-distilled alcoholic beverages produced from
different raw materials……………………………………….……………....9
a.Cereal Grains as raw materials……………………………....……………..9
b. Vegetables as raw materials……………………….…..…………....9
c. Fruit juice as raw materials……………………….….…………….10
d. Other Sources of raw materials…………...…………….................10
Table 2.3 Classification of wines………………………………………………….…...15
Table 2.4 Typical ranges of application of fining agents………………………………36
Table 3.1 Composition of different mashes…………………………..…………..…….47
Table 4.1 Chemical composition of the ginger wines……………...…………………..57
Table A.1 TSS reduction during fermentation of mashes………………………………73
Table A.2 Data obtained from analysis of samples of wines…………………………...73
Table A.3 Specimen cards for sensory evaluation by hedonic rating…………………..74
Table A.4 ANOVA table for chemical properties of ginger wines fermented by baker’s
yeast………………….…..……………………..……………………………75
Table A.5 ANOVA table for sensory characteristics of ginger wines fermented by
baker’s yeast……………….........…………..……………………………….76
Table A.6 Sensory evaluation scores of the wine samples…………................………...77
Table A.7 Chemical composition of the ginger wines fermented by true wine and baker’s
yeasts…………..…….………………………………………………………78
Table A.8 t-test table for chemical properties of the wines……....……………..………78
Table A.9 t-test table for sensory properties of the wines………………...…………….79
Table A.10 ANOVA table for turbidities of ginger wines………………...……………..79
Table A.11 Effect of bentonite on the clarification of ginger wine………..…..….……...80
Table A.12 Average chemical analysis of prize-winning high quality wines……….…...80
Table A.13 Major Wine producing countries of the world-1996………….………...…...81
Table A.14 Composition of some wines………….....……………….….……………….82

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List of figures
Figure 2.1 Simplified pathway of alcohol synthesis by yeast………….………………...18
Figure 2.2 The malo-lactic pathway……………………………………………………...22
Figure 3 Outline of Red Table Wine production……………………………………….22
Figure 3.1 Fermentation of ginger wine………………………………………………….48
Figure 3.2 Preparation of ginger wine……………………………………………………49
Figure 3.3 Clarification of ginger wine using bentonite………………………………….50
Figure 4.1 Effect of initial TSS on the TSS of the ginger wines …………………………52
Figure 4.2 Effect of ginger amount on the TSS of the ginger wines……………………...53
Figure 4.3 Effect of initial TSS on the alcohol content of the ginger wines……...………54
Figure 4.4 Effect of ginger % on the alcohol content of the ginger wines…………...…...54
Figure 4.5 Effect of initial TSS on the sensory properties………………………..………55
Figure 4.6 Effect of ginger amount on the sensory properties…………………..………..55
Figure 4.7 Effect of yeast type on the sensory properties of ginger wines fermented by true
wine and baker’s yeasts……………………………………………..…………61
Figure 4.8 Effect of bentonite on the clarification of ginger wine…………..…………….63

Part I
Introduction
1.1 General introduction
Alcoholic beverages are among the most popular and appreciated food products all over
the world (Ray et al., 2005). Large numbers of distilled and un-distilled alcoholic products
are enjoyed in different geographical regions throughout the world (Jones, 1985). Wine is
the end product of partial or complete alcoholic fermentation of the juice of grape (Prescott
and Dunn, 1987). It is also made from a variety of fruits, such as grapes, peaches, plums or
apricots etc. and saps of different palm tree (Okafor, 1972). Wine is an un-distilled
beverages having 6-20% ethanol by volume (Pearson, 1976). Wine represents a safe and
healthful beverage. It also provides calories and vitamins. Generally wine is made from
grapes. The grapes are crushed to squeeze out the juice and then are left for some time to
ferment (Amerine et al., 1972).
After this first step of winemaking, the primary fermentation stage that usually takes
around one to two weeks while yeast transforms majority of the sugars in the grape juice to
ethanol, which is alcohol. The resulting liquid is then transferred to several vessels for
secondary fermentation when the remaining sugar is slowly converted to alcohol and the
wine gets clearer in color. Some amount of the wine is then placed in oak barrels to age
before bottling that adds aromas to the wine.
Most of the wines, however, are placed inside bottles and shipped right away that can be
opened starting from after few months to twenty years for top wines. It is important to note
though that only a small percentage of wines will be tastier after five years, compared to
after one year. Wild yeast and other microorganisms are present on the skin of the grapes
and these pass into the juicy pulp (known as must) when the fruit is crushed. These are
destroyed by adding sulfur dioxide (or KMS) in the required quantity. Nowadays other
fruits are also used for winemaking. Many spices are used to flavor the wine (Manay and
Shadaksharaswamy, 1987).
Ginger wine is an alcoholic beverage made from a fermented blend of ground ginger
(Zingiber officinale Rosco.) and raisins fermenting by the yeast, Saccharomyces cerevisiae.

2
It is a popular beverage in Europe. The word drink is primarily a verb, meaning to ingest
liquids. Ginger is usually used to flavor a wine. It has many health benefits. Ginger wine
can be consumed by blending with whisky, brandy or rum.
The first documented appearance of Ginger wine occurred with the foundation of 'The
Finsbury Distilling Company' based in the City of London in 1740.
1.2 Statement of problem
Ginger is becoming the major cash crop for the mid-hill Nepalese farmers. Salyan, Palpa,
Tanahu, Syanja, Kaski, Nawalparasi, Bhojpur and Ilam are the leading districts for ginger
production. Most of the ginger is used as spices. The mother ginger root is harvested in
Ashad and Shrawan months. It is humid and heavy rainy season. So, most of the ginger is
decayed due to moist weather in a short period of time. There is no proper transportation
facility for marketing. There is no good market for the ginger. Nepalese farmers are not
getting a good profit by ginger production. It is very hard to achieve the returns of their
investment. So, if ginger is used for the production of ginger wine, farmers would get good
market for their ginger and their socio-economic status will be changed. Ginger has many
health benefits too. So, it would be a very valuable if we utilize ginger for making different
products such as wine, juice, candy, brandy that preserve for several months to years.
1.3 Significance of the study
My proposed work will be focused on the preparation of a good quality ginger wine by
using wine and baker’s yeasts. Ginger can also be used to prepare dry ginger candy. But it
is not an easy method. It requires a suitable dry weather and takes long time to prepare. It
can not be prepared in all seasons. Sugar is not easily available in the rural areas. Ginger
wine can be prepared easily by using baker’s yeast in rural areas which is as comparable to
the ginger wine made by using true wine yeast. It saves the ginger from decaying. If ginger
is used in winemaking, the people of Salyan, Palpa, Tanahu, Syanja, Kaski, Nawalparasi,
Bhojpur and Ilam will raise their economic status by the production of ginger wine and
brandy. Since ginger can be produced in large quantities in hill regions, we can utilize it
effectively for ginger wine production. Ginger wine is consumed in large quantity in
European and other countries. The ginger wine can be exported to those countries and
earned foreign currency. It helps to increase national income in our country.

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1.4 Objective of the study
The overall objective of the study is to prepare a good quality ginger wine.
The specific objectives of the study are as follows:
I. To determine the optimum amount of ginger and sugar in fermentation mash for
winemaking.
II. Quality comparison of ginger wines prepared by true wine yeast and baker’s yeast.
III. Clarification of ginger wine by using bentonite.
IV. To determine the physicochemical properties of the ginger wine
V. To evaluate sensory characteristics of ginger wines fermented by true wine and
baker’s yeast.
1.5 Limitations
I. The suitable temperature could not be adjusted. Wine fermentation requires 15-
20o
C for good quality wine. Ginger wine was prepared at higher temperature
(i.e.28-30o
C) than desired temperature due to technical constraints.
II. Clarification could be done by other fining agents but only bentonite was used due
to time constraints.
III. The prepared ginger wine could not be aged properly due to time constraints.
Ageing is an essential requirement for the good organoleptic qualities of wine.

Part II
Literature review
2.1 Introduction of ginger
Ginger (Zingiber officinilae Rosc.) is an herbaceous perennial plant of the family
Zingiberaceae which consists of 47 genera. The genus Zingeber consists of 80-90 species
among them Officinale is cultivated one (Borget, M. 1989). Ginger is becoming the major
cash crop for the mid-hill Nepalese farmers. It is grown successfully from Terai (100
meters above sea level) to mid hills (1500 meters above sea level).
Ginger is one of the oldest spices to be supposedly native to South East Asia, but like
many other tropical plant of economic importance, its exact origin is uncertain. It is
mentioned in early literature of China and India. The adventurer, Marco Polo, in recording
to his travels during the 13th and 14th centuries, noted that ginger was being cultivated in
South China and Malabar Coast of India (Leverington, 1983).
2.2 Varieties of ginger cultivated in Nepal
Ginger is one of the important spices as well medicinal plants in the country. It is
becoming the major cash crop of the mid-hill farmers of Nepal. Salyan, Palpa, Tanahu,
Syanja, Kaski, Nawalparasi, Bhojpur and Ilam are the leading districts for ginger
production.
As ginger rarely set seeds, the general mode of propagation is asexual. This leads to little
variation between forms grown over a wide geographical area (Lawrence, 1984). Therefore
the classification of cultivars of ginger is done according to their germplasm collected area,
such as Calicut, Cochin, Reo de Generio, Salyan, Ilam etc.
In Nepal, locally available ginger has two varieties- fibrous (NASE) and non fibrous
(BOSE). The germplasm collected from Salyan, Bhojpur and Ilam fall under the ‘BOSE’
variety and these are considered the best in quality (Sharma, 1997).

5
2.3 Composition of ginger
The ginger rhizome contains a mixture of an essential oil, a fixed oil, pungent compounds,
starch and other saccharides, proteins, cellulose, waxes, coloring matter, trace minerals etc.
Starch is the most abundant of these components (Jogi et al., 1972). Chemical composition
of ginger varies with varieties, climatic condition, soil condition, fertilizer used etc. Further
there is a great effect of maturity, handling, storage, drying and other processing methods
on the chemical composition of ginger. The chemical composition of green ginger is given
in table 2.1.
Table 2.1 The chemical composition of ginger
Component Value Watt and Merril, 1975
Value Swaminathan, 1974
Moisture (g) 80.89 87
Protein (g) 2.3 1.4
Fat (g) 0.9 1
Fibre (g) 2.4 1.1
Carbohydrate (g 12.3 9.5
Calcium (g) 0.02 0.023
Phosphorus (g) 0.06 0.036
Iron (g) 2.6 2.1
Carotene (mg) 40 40
Thiamine (mg) 0.06 0.02
Niacin (mg) 0.6 0.7
Riboflavin (mg) 0.03 0.04
Ascorbic acid (mg) 6 4
2.4 Ginger and its health benefits
Ginger has been revered for its medicinal and culinary benefits for centuries. The
underground stem known as the rhizome contains the most medicinal benefits of the plant.
The volatile oils of the ginger plant gives ginger its characteristic odor and taste. It is best
to use ginger in its fresh form to obtain the most health benefits from its use. Ginger has
the following health benefits:

6
1. Ginger can help to alleviate diarrhea, aid digestion and reduce flatulence. It also helps
to relieve the nausea associated with morning sickness and motion sickness. Ginger
also helps to neutralize stomach acid that can cause upset and diarrhea.
2. Ginger has natural anti-inflammatory properties. It helps to reduce the inflammation
associated with arthritis.
3. Ginger is a natural decongestant and antihistamine. It helps to relieve the congestion of
colds, and reduces fever as well.
4. Ginger may help to prevent the formation of blood clots by relaxing the muscles around
blood vessels. Ginger is also a natural blood thinner.
5. Ginger can help to lower cholesterol and prevent blood platelets from clumping
together. It also stimulates the circulatory system.
6. Ginger may also be beneficial in the prevention of heart disease and cancer, as well as
in the treatment of diabetes. Research continues to determine the effectiveness of
ginger in these areas as well as other health conditions.
(Source: http://www.ehow.com/facts_4924826_health-benefits-ginger.html)
2.5 Historical background of alcoholic beverage
Alcoholic beverages are among most popular and most appreciated food products all over
the world. Alcohol was discovered in 8327 B.C. on a warm afternoon by “Grog” who
returned to his cave and drank the fermented milk of a coconut that had been cracked and
left out in the sun. Beer and berry wines were made for the first time in 6400 B.C. while
Grape wines were made in 300-400 B.C. (Ray et al., 2005). Large numbers of distilled and
un-distilled alcoholic products are enjoyed in different geographical regions throughout the
globe. Alcoholic beverages are believed to have originated in Egypt and Mesopotamia
some 6000 years ago (Jones, 1985).
Despite this early application of microbiology, the ability of microorganisms to stimulate
the biochemical changes was demonstrated several years later. Gay Lussac first identified
alcoholic fermentation in 1810, but at that time yeast was not recognized as a causative
organism. Schwan in 1835 demonstrated that yeast could produce alcohol and carbon
dioxide when introduced in sugar-containing solution. He termed yeast Zuckerpilz meaning
sugar fungus from which the name Saccharomyces originated (Prescott and Dunn, 1987).
Saccharomyces group possesses almost all the credits of producing alcoholic beverages
(Tannanhill, 1937).

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The production and consumption of alcoholic beverage is one of the man’s oldest
activities. Today brewing, wine making and distilling are of major commercial importance
in many non-Islamic countries and, through taxation, can be an important source of
government revenue (Vernam and Sutherland, 1994).
There are different types of alcohols. Some are used in chemistry and industry, e.g.
isopropyl and methyl alcohol. Another type of alcohol, also known as ethanol has been
consumed by human beings for its intoxicating and mind-altering effects. The term
‘alcohol’, unless specified otherwise, refers to ethanol or ethyl alcohol.
2.5.1 Brief description of alcoholic beverages
There are many types of alcoholic beverages. They are briefly described as;
Wine: Wines are the oldest of the alcoholic beverages made by fermentation of grape
juice. Wine, strictly speaking, is a product of vine, but often includes all fermented liquors
obtained from different fruit juices (fruit wines). Wines differ greatly in their characters,
because grapes grown in different regions differ in composition, particularly in their
volatile components which contribute to flavor and bouquet and in the method used for
wine making (Amerine et al., 1972).
Wine is the end product of partial or complete alcoholic fermentation of the juice of
grape (Prescott and Dunn, 1987). It is also made from a variety of fruits, such as grapes,
peaches, plums or apricots etc. and saps of different palm tree (Okafor, 1072).
Wine is an un-distilled beverages having 6-20% ethanol by volume (Pearson, 1976).
Most of the natural wines contain 8-10% alcohol. Fortified wines contain about 20%
alcohol, which is sufficiently high to kill the microorganisms that attack natural wines.
Wines containing less than 14% alcohol are table wines, whereas those containing more are
dessert wines. The term wine is broadly used to include any properly fermented juice of
ripe fruits. The names of the fermented products are different according to the types of
fruits used. For example: the product obtained from the grape juice is known as wine,
similarly product from apple juice and pear pulps are known as cider and perry respectively
(CFRL, 1984).
The most common wines are produced from grapes. The soil in which the grapes are
grown and the weather conditions in the growing season determine the quality and taste of
the grapes which in turn affects the taste and quality of wines. When ripe, the grapes are
crushed and fermented in large vats to produce wine.

8
Beer: Beer is also made by the process of fermentation. A liquid mix, called wort, is
prepared by combining yeast and malted cereal, such as corn, rye, wheat or barley.
Fermentation of the liquid mix produces alcohol and carbon dioxide. The process of
fermentation is stopped before it is completed to limit the alcohol content. The product so
produced is called beer. It contains 4 to 8 percent of alcohol.
Whisky: Whisky is made by distilling the fermented juice of cereal grains such as corn, rye
or barley. Scotch whisky was originally made in Scotland. The word “Scotch” has become
almost synonymous with whisky of good quality.
Rum: Rum is distilled beverage made from fermented molasses or sugarcane juice and is
aged for at least three years. Caramel is sometimes used for coloring.
Brandy: Brandy is distilled from fermented fruits juices. Brandy is usually aged in oak
casks. The color of brandy comes either from the casks or from caramel that is added.
Gin: Gin is a distilled beverage. It is a combination of alcohol, water and various flavors.
Gin does not improve with age, so it is not stored in wooden casks.
Liqueurs: Liqueurs are made by distilling sugar and flavoring such as fruits, herbs or
flowers to brandy or to a combination of alcohol and water. Most liqueurs contain 20-65
percent alcohol. They are usually consumed in small quantities after dinner.
2.5.2 Classification of alcoholic beverages
There are different types of distilled and un-distilled congeneric alcoholic beverages all
over the world according to source of raw materials; some are listed in the following table
2.2.

9
Table 2.2 Classification of distilled and un-distilled alcoholic beverages produced from
different raw materials.
a. Cereal Grains as raw materials.
Source Name of fermented beverage Name of distilled beverages
Barley Beer, Barley wine Scotch whisky, Irish whiskey
Rye Rye beer kvass Rye whiskey, Roggenkon (Germany)
Corn Chichi, Corn beer Bourbon whiskey, Vodka
Sorghum
Burukutu (Nigeria), Pito
(Ghana)
Maotai, Gaoliang, types of Baijiu
(China)
Wheat Wheat beer Wheat whisky
Rice
Huangjiu, Choujiu (China), Sake,
Sonti, Makkoli,
Rice baijiu (China), Shochu and
Awamori (Japan)
Millet
Millet beer(Sub-Saharan Africa),
Tongba (Tibet)
b. Vegetables as raw materials.
Source
Name of
fermented
beverage
Name of distilled beverage
Juice of ginger
root
Ginger beer
(Botswana)
Potato and/ or
Grain
Potato beer Vodka: Poland and Germany, Aquavit or Brannvin:
Sweden, Akvavit: Denmark
Beets Pink vodka/ Woman’s vodka/ Girlie vodka (Russia)

10
c. Fruit juice as raw materials.
d. Other Sources of raw materials.
Source Name of fermented beverage Name of distilled beverage
Sap of
palm
Coyol wine (Central America), Tembo
(Sub-Saharan Africa), Toddy in
Nigeria, Tadi (Nepal)
Arrack
Honey Mead, Teg (Ethiopia) Distilled mead (“mead brandy” or
“honey brandy”)
Pomace Pomace Wine Raki (Turkey), tsikoudia (Greece),
grappa (Italy), Trester (Germany),
marc (France)
Milk Kumis or Kefir Araka
Source: htto://en.wikipedia.org/wiki/Alcoholic_beverage
Source
Name of fermented
beverage
Name of distilled beverage
Juice of grapes Wine, grapes wine Brandy, Cognac (France)
Juice of apples (“Hard”) Cider,
Apfelwein
Applejack (or apple brandy), Calvados,
Cider, Lambic
Juice of pears Perry, or Pear cider,
Poire (France)
Pear brandy, Eau-de-Vie (France)
Juice of sugarcane,
or molasses
Basi, Betsa- betas
(regional)
Rum (Caribbean), Pinga or Cachaca
(Brasil), Aguardiente, Tequila, Mezcal
Juice of agave Pulque Tequila, Mezcal
Juice of plums Plum wine Slivovitz, Tzuica, Palinca
Juice of pineapples Tepache (Mexico)
Juice of Bananas Urgwagwa (Uganda,
Rwanda)

11
2.6 Traditional alcoholic beverages of Nepal
Alcoholic beverages have played an important role in human spiritual and cultural life both
in Eastern and Western societies. Unlike in Europe and the Middle East, where indigenous
alcoholic beverages are produced primarily from fruit, alcoholic beverages are produced
from cereals in the Asia-Pacific region, and serve as an important source of nutrients.
European beer uses barley malt as the primary raw material, while Asian beer utilizes rice
with molded starters as the raw material. Beverages vary from crystal-clear products to
turbid thick gruels and pastes. Clear products which are generally referred to as
Shaosingjiu in China, Chongju in Korea and Sake in Japan, contain at least 15% alcohol
and are designated as rice-wine, while turbid beverages, such as Takju in Korea and Tapuy
in the Philippines which contain less contain less than 8% alcohol along with suspended
insoluble solids and live yeasts, are referred to as rice-beer (Haaed, 1999).
2.6.1 Jand
Jand is an alcoholic beverage (un-distilled) indigenous to Nepal. It is prepared by solid-
substrate fermentation of starchy cereals like corn, rice, wheat and millet. Murcha, a starter
culture, is used as the inoculum in traditional fermentation. Murcha contains saccharifying
molds, lactic acid bacteria and fermenting yeasts. Jand is therefore the result of concerted
action of these microorganisms on the cooked cereal (Rai, 2005).
2.6.2 Rakshi
Raksi (also spelt rakshi, rukhsi) is an un-aged congeneric spirit obtained by pot distillation
of the slurry of jand. The product likens whiskey and has highly varying alcohol contents
(K.C. et al., 2004), generally between of 15 and 40% (Subba et al., 2005). Several basic
researches have been done on raksi production from different cereals using murcha starter
as well as wine cultures isolated thereof (Rai, 1984) but there seems to be general lack of
attention towards process development such as preparation of good starter culture,
increasing efficiency of traditional distillation apparatus, and separation of fients and
foreshots for improving quality of raksi.
2.6.3 Toddy/ Tadi
It is a fermented sap of palm trees by natural contamination. In Nepal naturally fermented
palm sap used as alcoholic beverage is called “Tadi”. Traditionally, sap is collected

12
overnight in clay pots (with bottom containing a crust of microorganisms formed from the
previous fermentation), from the slit made at the top portion of the tree trunk. The tapped
sap, which is trickles down into the collection pot, is inoculated and fermentation sets
immediately. The sap is converted into sweet Tadi by the fermentation. This product is
white and effervescent (Dhakal, 2007).
2.7 History of wine making
As stated by sir John Malcohn in his first account of Persia during the regime of king
Jamshed, Viticulture flourished and it is he who is credited with the dictionary of
fermentation (Andrew, 1980). History of wines has left its traces in Near East, particularly
Mesopotamia (Iraq, Iran territory), later– in Persia (Iran), Egypt, Ancient Greece, Roman
Empire. Think of Greek classical pottery and Dionysus cavorting with his satyrs and
maenads and you will get a clue of the ancient history of wine that created immortal
legends. Egyptian history of wines origin in Nile delta– the fertile land where grapes grew
and white wine made from what is today called the Muscat grape of Alexandria. It is not
surprising that the early Egyptians attributed this drink with the god Osiris and used it
during funerary rituals.
Since Roman times, wine (potentially mixed with herbs and minerals) was assumed to
serve medicinal purposes as well. It was not uncommon to dissolve pearls in wine for
better health. Cleopatra created her own legend by promising Marc Anthony she would
"drink the value of a province" in one cup of wine, after which she drank an expensive
pearl with a cup of wine. From Rome winemaking greatly prospered under the Catholic
Church who held widespread influence over Christian Europe. Eventually, winemaking
capability and practiced extended to far-flung places like England who enjoyed wine
varieties of Sherry, Port and Madeira. Christian monks of France and Northern Italy kept
records of their winemaking practices and grape cultivation. By 1800, France would be
recognized as the best of the wine-producing regions of the world.
(Source: http.//www.metalimagination.com/winemaking.html).
The Pheonicians from Lebanon introduced the wine and its secrets to the Romans and
Greeks who subsequently propagated wine making and even dedicated a God to wine the
Roman Bacchus and the Greek Dionysus. Fermented beverages have been produced since
the Paleolithic period probably at first by accident from honey. Later, cereals were used

13
and then grapes and various fruits. During the Neolithic period, wines from fruits, and
especially from grapes, were more popular in Greek and Roman territory (Dhakal, 1988).
Heating wine to produce a caramelized or baked odor was known in the Roman period. In
the 19th century, it was first used in the Madeira Islands (Johnson, 1974).
Crude methods of clarification, preventing spoilage, and treating spoiled wines were
developed by the Romans (Kirk, 1969). Wine is probably the most widespread and
historically significant beverage starting from ancient times. Wine is the drink of kings,
just as it is the beverage of choice for ordinary people. Wine has played a major role in the
rise and fall of countless individuals, nations and even civilizations. History of wine is very
long, interesting and intricate at the same time; nevertheless, classification of wine is no
less capturing and complicated as its history.
Grape wine is found widely distributed throughout the world. The most important species
Vitis vinifera is believed to have been brought by man from Southern Russia to Asia
Minor. Europe is obviously the most important wine-producing area with more than 75%
on average and over 68% of wine production comes from European countries, with France
and Italy capturing nearly 45% of total production (Amerine et al., 1967). For the mass
production in wineries, new methodologies and technologies were implemented so called
modern wineries. (Source: http://www. Byronwines.com/iw_facilities.asp)
Modern wineries are automatic and computerized and are capable of producing 3-4
million liters of wine with only handful of people (Birch and Lindley, 1985). More
recently, the use of tower fermentation (Berry and Watson, 1987) with timer and
programmer for the production of both wine and cider has been demonstrated.
In Nepal, there are only three wineries, one in Basantapur, Tehrathum (Makalu wine
industries (P.) Ltd.) and others in Jomsom, Mustang and Pokhara (Hill Hut Winery) to
produce raspberry wine, cider and different fruit wines respectively.
2.8 Classification of wine
Types of wines are normally classified by vinification method, by taste, by vintage, by
wine style, and/or by quality. Vinification refers to how the wine is made. Vinification
wine classification refers to three major categories: table wines, sparkling wines, and
fortified wines. Types of wine can also be classified by taste. Table wines, for instance, are
classified by character as dry (not sweet), semidry, semisweet; sweet wines are classified
as dessert wines. Apart from palate, types of wines can also be distinguished by sugar and

14
alcohol percentage. Dry wine contains 2-3% of sugar and about 10% of alcohol– such wine
is the lightest. Semisweet wines have sugar 5-6% and alcohol 13-14%, while semidry
wines are a little bit sweeter than semisweet ones. Dessert or sweet wines contain the
highest percentage of sugar and alcohols than other types of wine– about 14-16%, and 16%
of alcohol. Table wines are also further classified by color, as red, white, or rose (pink). In
addition to this wine classification, wines may also be classified according to specific
flavors, types of grape they are made of and origins where this grape grew.
Table wines, also called still or natural wines, are consumed mostly with food, they tend
to compliment the meal. Table wines contain less than 14% alcohol. White dry wine is
usually served with seafood, fish, cheese, or nuts. Red dry wine is served with meals of
meat and vegetables that are roasted, stewed, smoked, etc. Fortified or dessert types of
wine, such as sherry or vermouth, are most commonly drunk before or after meals and are
served with various cakes, pastry, chocolate, fruits, etc. Fortified wines are also frequently
used in cooking. Concerning sparkling wines, for example champagne, is distinguishable
by its effervescence and is drunk for the most part on festive occasions such as weddings,
birthdays, and during the holidays.
Wines are usually named either by their grape variety or by their place of production.
Generally speaking, European wines are named both after the place of production (e.g.
Bordeaux, Rioja, Chianti, Cotnari) and the grapes used (e.g. Pinot, Riesling, Chardonnay,
Merlot). Wines from everywhere except Europe are generally named for the grape variety.
Whether you prefer vintage wine or not, whatever the classification of wine you like, wine
is an ideal gift for any special occasion.
Wines can be classified on various bases viz., (i) color, (ii) relative sweetness, (iii)
effervescence, (iv) alcohol content, and (v) the system used by Wine Advisory Board,
USA. However, the basic groups of wines are most easily distinguishable for the consumer.
They are (i) table wines, (ii) sparkling wines, and (iii) fortified wines. A summary of the
classification scheme is given in table 2.3.

15
Table 2.3 Classification of wines.
Basis of classification Class/ type Description Example
Color Red wine Contains the red coloring matter of skin,
pulp and seeds.
Burgundy
White wine Does not contain the red coloring matter,
pulp and seeds.
Rhine wine
Pink wine Low concentration of red coloring
matter is maintained.
Rose
Relative sweetness Sweet wine Contains up to 7% sugar. Sherry
(sweet)
Dry wine Contains less than 0.12% sugar. Sherry (Dry)
Alcohol content Natural Contains 8.5-16% alcohol by volume (%
abv)
Table wines
Fortified Contains 17-21% abv. Sherry
Effervescence Still Does not contain CO2 Chianti
Sparkling Contains CO2 (Natural or Artificial ) Champagne
Wine Advisory Board,
USA
Dessert wine Contains sugar; taken after meal Sherry
(Sweet)
Appetizer
wine
Dry; fortified; taken before meal Sherry (Dry)
Sparkling
wine
Contains CO2 Champagne
Red-table
wine
Natural; red in color Chianti
White-table
wine
Natural; pale yellow to straw color Rhine wine
Note: There is considerable overlapping of wine types in the classification shown above.
For example, a Red Table wine can at the same time is sweet, sparkling, fortified, or
natural. Similarly, a fortified wine can be sweet, sparkling, red, or white (Rai, 2002).
2.9 General cultural conditions for fermentation
Cultural condition refers to the environment of yeast i.e. fermentation media on which the
propagation of yeast as well as final quality of wine is largely depended (Varnam and

16
Sutherland, 1994). Following are the few parameters, which determine cultural condition
of the fermentation media.
2.9.1 pH
The optimum pH for wine production varies from types of the selected fruit but generally
3.8-4.5 is supposed to be optimum. At higher pH, the concentration of glycerine is
increased during fermentation whereas at lower pH, there is a noticeable effect of log phase
(Prescott and Dunn, 1987).
2.9.2 Temperature
The optimum temperature for the fermentation is dependent upon the types of wines
produced. For white wine, the temperature is 10-15o
C and that for the red wine is 20-30o
C
(Prescott and Dunn, 1987). There is possibility of ‘stuck’ fermentation if it is carried at
higher temperature. On the other hand, low temperature may delay onset of fermentation.
At high temperature, the loss of alcohol and aroma substance takes place. Also, a large
amount of by-product like glycerol, acetaldehyde may be formed. An imbalance of these
constituents can be very detrimental to wine quality. It has been reported that at higher
temperature the formation of higher alcohol decreases (Peynand and Gumiberteau, 1962).
The fermentation temperature for most white wines is in the range of 18o
C to 24o
C and
there is little interest in fermenting at higher temperatures due to the progressive loss of
volatiles under these conditions. The contribution of the fermentation temperature to white
wine aroma is directly related to the retention of grape-based aromas and formation of the
group of volatile byproducts referred to as fermentation bouquet (Boulton et al., 1997).
There are additional effects of fermentation temperature on the formation of glycerol
(Ough and Amerine, 1965) and the higher alcohols (Ough et al., 1966). The advantage of
lower fermentation temperature are the fresher and fruitier character of wine, smaller losses
of ethanol and less danger of producing volatile acidity (Prescott and Dunn, 1987).
2.9.3 Sugar concentration
The ‘must’ having very high sugar concentration imparts high osmotic pressure, which in
turn has a negative effect on yeast cells, since both growth of yeast and fermentation
activity are lowered. The tolerance of higher sugar concentration varies according to the
yeast species (Prescott and Dunn, 1987).

17
2.10 Wine yeast
Wine yeast is the member of the Saccharomyces cerevisiae group. The name originates
from the Greek word sakchar means sugar and mykes means fungus, referring to the strong
sugar fermenting properties of the genus in general. Although, Hansen regarded them as a
separate species, they are more ellipsoid in shape than the round or oval cells of brewery
and bakery yeasts. Hansen restricted the name S. ellipsoideus to them. In the nomenclature
of Dutch school, these yeasts are classified as a variety of S. ellipsoideus and consequently
named S. cerevisiae var. ellipsoideus (Austin, 1968).
Good wine yeast is one which will impart a vinous or fruit like flavor, will ferment sugar
to a low content producing 14-18% alcohol, and is characterized by remaining in
suspension during fermentation and than agglomerating to yield a coarse granular sediment
that settles quickly and is not easily disturbed in racking (Pederson, 1971).
Good wine yeast should have the following four properties:
1. High alcohol tolerance, i.e. the yeast should continue to ferment despite the
increasing concentration of the alcohol, giving stronger, drier wines with up to 16%
alcohol (v/v), or even up to 18% (v/v) where the yeast is fed by periodic additions
of sugar in small amounts.
2. Good degree of agglutination, i.e., the tendency of the yeast to flocculate into small
lumps that give a cohesive sediment as fermentation ceases, so that racking is
simple and the wine clears easily.
3. Steady, persistent fermentation capacity; this leads to wines of better quality than
when the fermentation falls away after a tempestuous start.
4. Absence of unpleasant flavors generated by dead and dying cells (Austin, 1968).
2.11 Alcoholic fermentation
There are different kinds of alcohols, but when the term is used loosely as by winemakers,
it invariably applies to the potable alcohol called ethyl alcohol or ethanol. It mixes easily
with water in any proportion and where quantities are mixed there is a contraction in
volume. It has a low boiling point, 78.4o
C, compared with water. It burns easily in air, so
that oxidation is possible and then gives a blue, smokeless flame, producing water and
CO2. Ethyl alcohol is produced by the zymase complex of enzymes in yeast (Austin,
1968). There are three main classes of alcoholic beverages; wines, malted beverages and

18
distilled liquors (Lal et al., 1987). The essential step in all the fermentation processes is the
conversion of glucose into alcohol by yeast (Manay and Shsdasharaswamy, 1987).
The intermediate products are methyl glyoxal (CH3:OCH:O), Acetaldehyde (CH3CHO)
and pyruvic acid (CH3COCOOH).
Alcoholic fermentation is simply the production of alcohol by using carbon and nitrogen
substrate (Kaushik and Yadav, 1997). Sugar and nitrogen compounds are the principal
substrates for alcohol fermentation (Prescott and Dunn, 1987).
2.11.1 Biochemistry of alcohol fermentation
Alcoholic fermentation is an anaerobic process (i.e. takes place in the absence of air).
Microorganisms utilize the carbohydrate present in the materials to obtain energy for
growth and metabolic activities, leading to the formation of alcohol. Monosaccharides
(hexoses) are directly fermented. The flow of carbon in ethyl alcohol formation takes place
via the well known Embden-Meyerhof-Parnas pathway (Patel, 1999). The formation of
alcohol from sugar is accomplished by yeast enzymes which are contributed by the
growing yeasts. S. ellipsoideus is the true wine yeast. The organism uses EMP pathway,
generating two ATPs per mole of glucose converted to ethanol, plus CO2. Ethanol, which
is the end product, is primary metabolite. In an industrial fermentation, the basic strategy is
to maintain Crabtree effect during the fermentation. A truncated form of the metabolic
pathway for ethanol synthesis is given in Fig. 2.1.
Fig. 2.1 Simplified pathway of alcohol synthesis by yeast.
+C6H12O6 C2H5OH 2CO2
2ADP2ATP
Glucose 2[1, 3-di P glycerate]
4 ADP
4 ATP
4 Pyruvate
2 Acetaldehyde
2 [NAD + H+
]2 [NAD]
Alcohol dehydrogenase
2 Ethanol CO2

19
2.11.2 Malo-lactic fermentation
It refers to secondary fermentation in which lactic acid bacteria are allowed to metabolize
malic acid to lactic acid and carbon dioxide. This fermentation is particularly useful if the
titrable acidity of wine is to be reduced. Wines with low levels of acidity should be
protected from malo-lactic fermentation: wine quality decreases if the acid level falls too
low. Malo-lactic fermentation can be easily prevented by early racking, cool storage, and
maintaining 100 p.p.m. or more of SO2. On the other hand, if such fermentation is desired,
it can be facilitated by leaving the wine on the lees (yeast sediments) for prolonged periods
at higher temperatures. This storage causes lysis of yeast cells and releases amino acids and
other nutrients needed for the growth of the ‘contaminant’ lactic acid bacteria.
Malo-lactic fermentation has an important bearing in the quality of wine. It is a natural
way of reducing acidity in wine. Besides, the fermentation also results in wines with
greater softness and mellowness. The bacteria implicated for malo-lactic fermentation are
Leuconostoc oenos, Lactobacillus, and Pediococcus, the first one being the most important
(Rai, 2005). The biochemistry of fermentation is given in figure 2.2.
Figure 2.2 The malo-lactic pathway.
2.12 Technology of wine production
Winemaking starts during the time of harvest when grapes are selected and placed in
containers. After harvesting, the grapes are crushed to squeeze out the juice and then are
left for some time to ferment. The winemaking technology of red and white wines also
differs. If red wine is desired, the skins are left to soak in the juice for a while so that the
wine would take the skin’s color. In order to make white wine, the juice is extracted with
COOH
COOH
CH2
COOH
L-malic acid
L-malate dehydrogenase
Pyruvate+ CO2
Malo-lactic enzyme
L-lactose dehydrogenase
CH3CH2COOH

20
minimal contact from the grape skin. After this first step of winemaking, the primary
fermentation stage that usually takes around one to two weeks while yeast transforms
majority of the sugars in the grape juice to ethanol, which is alcohol.
According to winemaking technology, the resulting liquid is then transferred to several
vessels for secondary fermentation when the remaining sugar is slowly converted to
alcohol and the wine gets clearer in color. Sweet wines are created by allowing some
residual sugar to remain before or after fermentation or by adding another alcoholic
beverage to kill the yeast before fermentation is completed. Some amount of the wine is
then placed in oak barrels to age before bottling that adds aromas to the wine. Most of the
wines, however, are placed inside bottles and shipped right away that can be opened
starting from after a few months to twenty years for top wines. It is important to note
though that only a small percentage of wines will be tastier after five years, compared to
after one year.
Wild yeast and other microorganisms are present on the skin of the grapes and these pass
into the juicy pulp (known as must) when the fruit is crushed. These are destroyed by
adding sulfur dioxide (or KMS) in the required quantity. If the sugar content is low,
sucrose is added to the desired strength and the pH is adjusted to 3.2 to 3.4 by the addition
of tartaric acid. Next, the must is inoculated with a wine culture of actively growing yeast
(S. ellipsoideus). The temperature and duration of fermentation depend upon whether dry
or sweet wine is required. Fermentation usually lasts 4-10 days.
When fermentation is complete, the clear wine is siphoned from the yeast sediment into
barrels (racking) and the wine is allowed to age. During this period, secondary
fermentation takes place and wine also losses its raw and harsh flavor and mellows down.
During this period of maturation, clarification takes place in natural way. It can also be
achieved by fining and filtration. Next, the wine is bottled and allowed to mature; the time
of this maturation extends to a number of years depending upon the quality desired (Manay
and Shadaksharaswamy, 1987).

21
2.12.1 Selection of raw material
A suitable raw material is chosen to function as a substrate. Compared to cereals, fruit
juices are more readily utilizable substrate by yeasts for the alcoholic fermentation. The
later is also a suitable media for the yeast to grow (Varnam and Sutherland, 1994). Good
raw material for fermentation should be clean, sound, mature, impart from any taste and
odor and good source of carbon and Nitrogen with sufficient amount of fermentable sugar.
(Source: http/www.austwine/0089a/rm.html).
2.12.2 Blending/ Crushing
This step is carried out to extract the juice from the fruit. It has been suggested that the
process should be very gentle (Vernam and Suthearland, 1994). If the blending and
crushing machine is constructed of mild steel or cast iron then iron causes ‘ferric casse-
cloudiness’ of wine due to iron; actually iron will react with the tannin of the juice to form
ferric-tannin complex. Bronze equipment is also used but may cause dissolution of copper
and tin from bronze equipment and it will affect the color. Usually, stainless steel is used
for the crushing machine. Water may be added during blending/crushing for smoothness of
operation.
2.12.3 Sulphiting/ Preservatives
The antiseptic and antioxidant properties of sulfur dioxide are taken advantage of both in
connection with treatment of musts prior to fermentation and later in the winemaking
process. The dosage of SO2 usually ranges between 100 and 200 p.p.m. (Douglas and
Considine, 1982). SO2 is added before the fermentation process to prevent air oxidizing the
juice and converting the alcohol into vinegar. The air has bacteria principally Acetobacter
i.e. it is alive in the presence of air of oxygen, takes of the oxygen from the must to let the
wine yeast which is anaerobic condition convert the fruit sugar into alcohol. SO2 also
forms a coating on the surface of juice to prevent the air entering the juice (Andrew, 1980).
2.12.4 Yeast
Wine yeasts are the member of Saccharomyces and consequently of great individual
importance (Austin, 1968). A good quality of wine yeast should have the following
characters (Vernam and Sutherland, 1994):
• Introduction of flocculation and reduction of H2S production.

22
• Reduction of higher alcohol production.
• Improvement of fermentation efficiency.
• Resistance of ethanol.
• Resistance of killer activity.
Fig. 2.3 Outline of Red Table Wine production
Red table wine
Bottling, Labelling, Casing
Secondary Fermentation and Filling
Racking, Blending, Fining,
Malo-lactic fermentation
Filtration and Tartarate Stabilization
Polishing
Pasteurization
SO2
(75 ppm)
Yeast
Press wine
Propagation
Free-run wine
Primary Fermentation
Drawing off and Pressing
Purple grapes
Destemming
Crushing
Must
Must Treatment
Pomace
SO2 (75-125 ppm)

23
2.12.4.1 Inoculum Development and Pitching
Sufficient quantity of inoculums (pitch) is developed before the preparation of must. The
developing medium should have law sugar concentration so that the ‘Pasteur Effect’ is
maintained and maximum growth is necessary for the respiration of growing yeast cells.
The medium should, preferably, be the juice of the same fruit so that the yeast is adopted
with the fruit juice composition. Pitching is done when the culture of the pitch is at its
optimum stage of growth. Vigorous agitation is done after pitching to help distribute the
culture and also to help in their initial growth (Karki, 2001).
2.12.4.2 Fermentation
In alcoholic fermentation by yeast, which is an anaerobic process, sugar (or glucose) is the
substrate and alcohol is produced as the product along with carbon dioxide. According to
the Gay-Lussac’s equation, theoretical yield of 51.1% alcohol (ethanol) and 48.9% CO2 of
the weight of the sugar fermented, is possible. This is biologically unobtainable and
possible only in absence of yeast growth and loss of alcohol as vapor (Karki, 2001). The
yield of alcohol varies from 47.87 to 48.12% and of CO2 from 47.02 to 47.68% of the
weight of sugar fermented (Gvaladez, 1936). Fermentation is the soul (heart) of wine
making. All the desirable reactions take place during this step, so most of wine makers pay
strict attention to this stage. Fermentation is the process of adding wine yeast (technically
termed as S. ellipsoidues) to fresh juice to convert the natural sugar to ethyl alcohol. In this
process, CO2 is simultaneously released making fermentation violent at first and then slow.
The yeast added is 1-3% of the volume of the juice. Generally, 14 days is required for
complete alcoholic fermentation.
Most of the fermentation takes place in three stages.
• An initial stage during which time the yeast cells are multiplying.
• A very vigorous stage accompanied by bubbling and marked rise in temperature.
• Quiet fermentation that can proceed for quite along time at a lower and lower rate.
Fermentation time may range from 2-20 days depending upon numerous variables- types
and condition of fruits, type of wine made, and climatic conditions. Among others
temperature is quite critical to the fermentation process (Douglas and Considine, 1982).
The optimum temperature for fermentation of red wine is higher than that of white wine.
The optimum temperature is believed to be 21.1-27.4o
C (Johnson and Peterson, 1974). At
temperature above 90o
F (32.2o
C), it is likely that wine flavor and bouquet will be injured.

24
High temperature also encourages heat tolerant bacteria to produce acid, mannitol and off
flavor (Douglas and Considine, 1982).
At the usual total sugar content of 19-23%, alcoholic fermentation proceeds rapidly and,
with alcohol tolerant strains of yeast, to completion, producing about 10-12.5% alcohol (by
volume) (Johnson and Peterson, 1974). If sugar content is greater than 23%, the high sugar
content may inhibit fermentation and the rate of fermentation, form glycine for example,
but is primarily derived from hydrolysis of naturally occurring pectin. The amount of
higher alcohols produced is less when ammonium phosphate is added prior to
fermentation. At very low concentration, the higher alcohols may play a desirable role in
sensory quality (Amerine et al., 1967). The oxidative conditions during fermentation favor
higher alcohol production (Guymon et al., 1961). Glycerol production is favored by low
temperature, high tartaric content and by addition of SO2. Most of the glycerol develops in
the early stages of fermentation. Most enologists consider that glycerol is of considerable
sensory importance because of its sweet taste and its oiliness (Gentillini and Cappelleri,
1959).
Acetaldehyde is a normal by-product of alcoholic fermentation. Acetaldehyde retention is
much greater when SO2 is added before the fermentation (Keilhofer and Wurding, 1960).
The primary source of acetaldehyde is from enzymatic process, i.e., in the presence of
yeast (Kielhofer and Wurding, 1960). Acetaldehyde reacts with ethyl alcohol to form
acetal, a substance with a strong aldehyde like odor, found very little in wines.
The tartaric, malic and citric acids of the must are found in the resulting wines but in
decreased amounts. They are important constituents of wine not only for their acid taste but
also they protect the wine from spoilage, maintain the color, and are themselves sometimes
attacked by microorganisms. Malic acid disappears during alcoholic fermentation to the
extent of 10 to 30%.
Succinic acid is a product of alcoholic fermentation. Lactic acid has a slight odor and is a
weak acid. It is a constant by-product of alcoholic fermentation, 0.04 to 0.75 g/L. Carbonic
acid constitutes a very special case for both still and sparkling wines. It has no odor and
very little taste. But it does have a feel and disengagement of the bubbles from wine
probably brings more oxygen away from the surface of wine (Amerine et al., 1967).
The end of fermentation is signaled by a clearing of the liquid, by a vinous taste and aroma,
and by a drop in temperature, and can be confirmed by checking degrees balling (sugar
residual) (Douglas and Considine, 1982).

25
2.12.4.3 Factors influencing fermentation
Various factors influence the course and consequence of the fermentation. These are
briefly discussed below.
2.12.4.3.1 Yeast culture
Yeast culture plays important role in winemaking. The pattern and end products of
alcoholic fermentation are greatly affected by the type of yeast culture utilized. The natural
wine culture and wine culture also produce wine with differing chemical constituents,
which may alter the organoleptic qualities of wines. Natural yeast flora of wine (i.e. raisin
culture) is a mixed culture, containing the wine strain of wine yeast, Saccharomyces
cerevisiae var. ellipsiodeus. It is said that the mixed flora produce wines with motalre
complex distribution of aroma components than wine fermented with S. cerevisiae (Reed,
1987).
Several species of Saccharomyces are the more important yeasts for winemaking, and
they constitute the true wine yeasts. The physiological properties of the yeast culture are of
importance in winemaking (Prescott and Dunn, 2004). The strain of yeast to be used for
alcohol fermentation should possess the following selective features:
1. Should be a sufficient strain. In other word, it should produce a large quantity of
alcohol.
2. It should be a fast growing strain.
3. It should have a high tolerance to alcohol, as well as to osmotic pressure.
4. It should possess uniform and stable biochemical properties.
2.12.4.3.2 Sugar and its concentration
Generally, monosaccharides are the normal and preferred substrates for the alcoholic
fermentation by yeast. The concentration of sugar determines the rate of fermentation.
High sugar concentration exerts high osmotic pressure which has negative effect on yeast
cells since both growth and fermentation activities are lowered. The inhibition is further
increased by ethanol which is formed during fermentation. The tolerance of high sugar
concentrations differs for various yeast species (Prescott and Dunn, 2004). The optimum
sugar concentration for maximum speed of fermentation is fairly low, perhaps only 1 or 2
percent. The maximum alcohol content in a single fermentation is obtained with musts of
from 25 to 35 percent sugar. The maximum alcohol content obtainable in normal winery

26
practice is about 16%; however, this varies with strain of yeast, temperature, conditions of
aeration, and method of conducting fermentation. The rate of fermentation is rapid below
25% sugar concentration of the must. Above 25% sugar concentration, the fermentation
gets retarded and at even higher concentration i.e. about 70%, most wine yeast will not
ferment the sugar. The inhibitory effect of high sugar is partly owing to the osmotic effect
(Amerine et al., 1967).
2.12.4.3.3 Sulphur-dioxide
The biological effect of SO2 comprises an inhibition of undesirable the microorganisms of
the must including acetic acid bacteria and lactic acid bacteria, which affect the course of
fermentation and quality of wine negatively. The chemical effect of SO2 is to bind
acetaldehyde which is formed during fermentation and which has undesirable organic
properties. Further, SO2 is added to prevent oxidative reactions of enzymatic or non-
enzymatic nature. For must with low total acidity, it is often desirable to use So2 to inhibit
malo-lactic fermentation. The SO2 is also desirable to suppress undesirable yeast species
such as Kloeckera apiculata and Metschnikowia pulcherrima on the must to retain good
wine quality. SO2 has also a direct effect on the course of the fermentation by
Saccharomyces yeasts. It delays the onset of fermentation, and the lag period is longer the
greater the amount of H2SO3 added to the must (Prescott and Dunn, 2004). However in
spite of its some desirable properties, SO2 is never added in base wine for brandy
manufacture due to its adverse effects on the quality of volatile acids is a advantage of
fermentations under CO2. Also, the metabolism of lactic acid bacteria is not inhibited
which may result malo-lactic fermentation and its undesirable consequences (Koch et al.
1953). In alcoholic media, the inhibition of yeast growth due to CO2 pressure is increased.
At relatively low CO2 concentrations of 0.6 to 1.8 g per liter, the growth is inhibited.
However, this effect depends also on the original yeast cell counts in the medium, and this
is also true at higher CO2 concentrations (Haubs et al., 1974).
2.12.4.3.4 Acids and pH
Yeasts are not very sensitive to the amounts of fixed organic acid but there may be some
effect of organic acids on the by-product of alcoholic fermentation (Amerine et al., 1967).
Microbiologically, the low pH (4.5 or below) is considered a favorable and selective factor
for wine fermentation. Most undesirable bacteria are inhibited at lower pH. For yeast, a pH

27
range between 3 and 6 is most favorable for growth and fermentation activity. A change in
pH can affect the formation of fermentation by-products. For instance, at higher pH values
the concentration of glycerine is increased. There is a positive relationship between the pH
of the must and the formation of pyruvic acid (Rankine, 1967A).Within the range from pH
3 to 4, there is a noticeable effect on lag phase and fermentation activity. At higher pH
values, the lag phase is reduced and fermentation activity increased (Ough, 1966A, B). The
effect of pH on growth and fermentation activity depends also on the concentration of
sugar and ethanol (Neish and Blackwood, 1951; Trautwein and Wassermann, 1931).
2.12.4.3.5 Temperature
The optimum temperature for fermentation by most wine yeasts is between 71.6o
F and
80.6o
F (Schanderl, 1959).However, temperature has many other effects besides its direct
effect on yeast growth and activity. These are due to losses of alcohol and aromatic
constituents at higher temperatures and to the by-products formed as well as to direct
effects on the efficiency of fermentation. Temperature affects yeast and consequently the
course of wine fermentation considerably, and a number of factors should be considered
for the selection of proper temperature. The fermentation metabolism of yeast can be
carried out within a rather large temperature range. Maximum value for S. cerevisiae is
near 40-45o
C (White and Munas, 1951) and minimum temperature approaches to 0o
C
(Osterwalder, 1934; Saller, 1955). Temperature also affects the formation of by-products.
With higher temperature within the 15-35o
C range the concentration of glycerin, acetone,
2, 3-butanediol and acetaldehyde increase (Lafone, 1955; Rankie and Bridson, 1971).
Similarly, formation of acetic acid and other volatile acids, pyruvic acid and 2-ketoglutaric
acid also increase with increase in temperature. Whereas the formation of higher alcohols
decreases with increase in temperature. Whereas the formation of higher alcohols decreases
with increased the fermentation temperature having a maximum concentration at 20o
C
(Dittrich, 1977). The temperature sensitivity of yeast is also affected by the ethanol formed
during fermentation.
2.12.4.3.6 Nitrogen
Yeasts readily assimilate amino acids but proteins can be hydrolyzed and used for cell
growth. Between 50 to 70% of total nitrogen of musts can be assimilated by yeasts
(Tarantola, 1955). The quantity of nitrogenous substances is entirely adequate for a

28
vigorous fermentation, and under normal circumstances there is even excess. Generally,
nitrogen is not required for grape juice, but fruit musts are often deficient in nitrogen. So,
urea or ammonium phosphate must be added. Nitrogen source addition is used to check the
formation of fusel oil, which is formed due to the action of yeast on amino acids. The
member countries of European economic country permit the addition of up to 30 gm/hL of
ammonium phosphate or ammonium sulfate to provide additional nitrogen in readily
assimable form (Reed, 1987).
2.12.4.3.6 Minerals and growth factors
The normal course of alcoholic fermentation requires magnesium, potassium, zinc, cobalt,
iodine, iron, calcium, copper and anions of phosphorous and sulfur. For growth alone
yeasts require copper, iron, magnesium, potassium, phosphorus, and sulfur. Adequate
amounts are supplied by grape and fruit juices. The presence of excessive iron (over
6p.p.m.) or copper hinders the fermentation of sparkling wines (Schanderi, 1959). Some
desirable growth factors for yeast are biotin, inositol, nicotinic acid, pentothenic acid, p-
aminobenzoic acid, pyridoxine and thiamine (Karki, 2001).
2.12.4.3.7 Oxygen
Oxygen is necessary for the maximum growth of yeast. But alcoholic fermentation is best
in an anaerobic condition. Here less of sugar is used by the yeast in respiration and there is
no oxygen to interfere with enzymatic activity. Aeration during normal fermentation may
results in wine with higher aldehyde content and darker color (Amerine et al., 1967).
2.12.4.3.8 Ethanol toxicity
Yeasts show some adaptive responses to the challenge of ethanol toxicity. The adaptive
behavior of yeast to ethanol response is also found in the relative resistance of the cells to
ethanol formed during fermentation, in contrast to the high sensitivity of cells to ethanol
supplementation. The most important response is that to the major toxic effect, the
disruption in the membrane permeability and change in fluidity. Increased ethanol
concentration can cause a decrease in yeast viability, reduction in yeast growth and
reduction in the rate of ethanol production. Slapack et al. reported that wine range of
cellular function is affected by ethanol, including inhibition of solute uptake, denaturation
and inhibition of glycolytic enzymes, uncoupling of oxidative phosphorylation and the

29
induction of peptic yeast strains. Saccharomyces cerevisiae may tolerate up to 17% by
volume ethanol concentration (Ribereau-Gayon and Peynaud, 1960).
2.12.5 Problems during fermentation
Different problems may arise during fermentation such as stuck fermentation, off-flavors
production, methanol production, and contamination with undesirable microorganisms.
There are two general classes of problems for winemakers that can arise during the
alcoholic fermentation: sluggish or stuck fermentations and off-flavor production.
2.12.5.1 Stuck fermentation
Premature arrest of alcoholic fermentation is an occasional but continuing problem for
wine makers. It may manifest itself as sluggish activity during mid and later phases of
alcoholic fermentation. Whereas in other cases cessation of fermentation activity may be
abrupt. In either case, the resultant wine may have perceivable (an often objectionably
high) levels of sugar with decreased production of alcohol. The causes of sluggish and
stuck fermentations include fermentation at temperature extremes, nutritional deficiencies,
osmo-regulation, ethanol toxicity, and in low-temperature fermentation, long-term
anaerobiosis. Such problem is generally treated with addition of deficient nutrition such as
nitrogenous compounds e.g. di-ammonium phosphate, and provision of optimum
temperature along with aeration for the reactivation of yeast (Kenneth, 1997).
2.12.5.2 Production of off-characters
Saccharomyces strains have also been implicated in the production of certain volatile
phenols in wine (Chatonner et al. 1993). During fermentation, production of off-characters,
off flavors or off aroma compound detract from overall wine quality. An important class of
spoilage compounds is sulfur-containing volatiles which have very unpleasant odors.
Although they are produced in traces, they cause damaging effect on the quality. Foremost
among the sulphur containing volatiles is hydrogen sulfide (H2S) (Baulton, 1997). To
prevent this problem very careful control of fermentation conditions is worthwhile.

30
2.12.5.3 Methanol production and its quality
Small amount of methanol is inevitably present in brandies, but if significant quantity is
formed during fermentation, large accumulation may result in distilled product which may
be detrimental to health. Methanol is produced by the demethylation of pectin present in
the substrate by fruit pectin esterase enzymes. Yeast does not form an enzyme capable of
hydrolyzing pectin and consequently the reaction does not commonly occur in fruit
fermentation but the fruit itself contains this enzyme. Methanol is very toxic to humans
with a fatal internal dose of 60-250 ml. The methanol production can be prevented by
inactivating the fruit pectin esterase enzymes before fermentation with heat treatment and
by obstructing the contamination of the fermentation with molds and bacteria.
2.12.5.4 Activity of undesirable microorganisms
Low pH values of the must are inhibitive for most of the bacteria but two types of bacteria
viz. lactic acid bacteria and acetic acid bacteria, which may start malo-lactic fermentation,
metabolizing the malic acid to lactic acid and CO2. The malo-lactic fermentation is
desirable in some cases, but generally it lowers the acidity causing rise in pH and
susceptibility of wine to further spoilage. Similarly, lactic acid bacteria ferment the sugar
into lactic acid and other volatile acids, causing an undesirably high acidity. Acetic acid
bacteria are aerobic and if they get favorable condition, they grow on the must and change
the produced ethanol into acetic acid (Reed, 1987).
2.13 Racking
After completion of fermentation, the wine must be separated from the dead cells, which
decomposes and give off flavors and odors to wine (Andrew, 1980). This dead yeast settle
at the bottom of the fermentation vessel and the wine is carefully transferred (siphoned) to
other vessel without disturbing the dead yeast leaving some wine at the bottom called lees.
The advantages of racking are:
• It helps removing CO2.
• It raises O/R potential, which retards the formation of H2S.
• It clarifies the wine.

31
2.14 Clarification and fining
Clarification by conventional racking process is a long process. To hasten this, certain
agents commonly called fining agents are added during racking. Fining is a traditional
method of bringing about clarification. Fining agents may be used during ageing as well.
They not only clarify the wine (by physical adsorption) but also help to remove excess
tannins (Rai, 2005). The purposes of clarification and fining during wine processing
include removal of excessive levels of certain wine components, achieving clarity, and
making that clarity stable especially from a physiological viewpoint. The materials used for
these reasons are collectively referred to as fining agents. Examples of such fining
reactions are: This is a process of converting cloudy wine into clear wine. This may be
done by adding gelatinous substances such as icing glass, egg white, bentonite and tannin.
Pectin hydrolyzing enzymes are also used in the clarification of wine (Andrew, 1982).
After clarification, the wine is passed through fine filters for filtration. The pad filters are
most common. In order to increase filter life, diatomaceous earths are added to wine during
filtration. These mix with mucilaginous materials and maintain the capacity of the filter for
longer times i.e. increase filter capacity. Recently membrane filters have been widely
employed for wines. These have uniform but small pore size so that a very large percentage
of the filter-surface is available for filtration. They also greatly reduce the number of
bacteria (Johnson and Peterson, 1974).
2.15 Stabilization of wine
Because of the unknown nature of the wine, it is generally good practice to stabilize them
against microbiological changes by use of antiseptics such as sorbic acid or its potassium
and sodium salts in amounts ranging from 300 to 1000 p.p.m. An alternative is to
pasteurize the wines after bottling. Another alternative may be to flash pasteurize, fill into
clean bottles, and seal using clean closures (Chan, 1983).
2.16 Maturing and aging of wine
This is one of the most interesting and one of the most important, yet one of the most
complex processes of wine making. This takes place naturally by retaining the wine in oak
barrel for one or two years to gain maturity and pick up soft and mellow characters from
the oak wood. Andrew (1980) found that maturation can be artificially induced by

32
agitation, heating, refrigeration and electrical impulses. The bouquet and aroma of wine are
developed during aging (Banwart, 1987).
Aging of wine for long periods of months to years produces desirable changes in body
and flavor of wine. In addition, malic acid of grape juice is fermented by lactobacilli during
aging to give lactic acid and carbon dioxide and also decrease the acidity (Sivasankar,
2005).
Aging is one of the most interesting and important yet one of the most complex process
in winemaking. Newly fermented wine is cloudy, harsh in taste, yeasty in odor and without
the pleasing bouquet that develops later in its history (Amerine et al., 1967). The wine is
aged to reduce the acidity and to develop a characteristic bought. The main acid in most
wines is tartaric acid but, in some red wines, malic acid is present in a high concentration.
In these, secondary malo-lactic fermentation by lactic acid bacteria converts malic acid to
lactic acid to reduce the acidity and to improve the flavor and aroma. Lactic acid bacteria
produce small amount of aldehydes and lactic and acetic acids, which give the product a
characteristic aroma and flavor (Fellows, 1990). Aging of wines improves the flavor and
bouquet due to oxidation and formation of esters. These esters of higher acids formed
during aging give the ultimate pleasing bouquet to the well aged wine. Aged wine may be
polished by filtration to give a clear, bright appearance prior to bottling (Desrosier and
Desrosier, 1978).
2.17 Bottling
This is done before the blended wine has lost its bouquet, fineness, quality and color.
Bottles are cleaned and dried with hot air. Cool and dry weather is chosen for this purpose.
Bottles are closed with a fine, soft supple cork applying pressure with the finger. Corks are
finally sealed with Spanish wax (Andrew, 1980).
2.18 Pasteurization
Pasteurization is the process used to kill microorganisms present in the wine so that
fermentation is stopped. Pasteurization is applied in one of the three ways:
1. By flash pasteurizing and returning to the storage tank.
2. Flash pasteurizing into the final bottles and
3. Pasteurization by heating the filled and sealed bottles.

33
The time temperature relationship for pasteurization of wine is: vegetative yeast cells are
killed at about 40o
C while yeast spores are only killed at 57o
C (Desrosier and Disrosier,
1978). The quality of some wine is reduced by pasteurization while that of other may be
improved. Pasteurization inactivates the enzymes but injures the quality of the product
(Johnson and Peterson, 1974).
2.19 Finishing
The traditional method of finishing the wine was to turn the bottles on end, place them in
racks at about 45o
angle and turn them to the left and right daily to get the yeast deposit
into the neck of the bottle and on the cork. The process is called riddling “reumage”. The
temperature of the whole bottle is then reduced to about 30o
C to 40o
C. The neck of the
bottle containing the yeast deposit is then frozen (by placing in brine or other freezing
solution). When the cork is removed, the solid plug containing the yeast is ejected. This is
called disgorging (Johnson and Peterson, 1974).
2.20 Storage and ageing of wine
Actually racked wine contains some suspended particles. Racked wine is flash pasteurized
in order to coagulate the suspended particles. After pasteurization it is kept at room
temperature for 1-2 days, then at -3 to -4o
C for 2-5 days. Then it is filtered in the cold state
(-3 to -4o
C) and transferred to storage tank. Wines are aged in bottles, barrels, tanks or
puncheons. The tank may be wood, concrete or metal ((Dhakal, 1988).
A wine cellar should be maintained at a uniform temperature of 60o
F and a humidity of
50%. When stored, each bottle of wine must be laid in a horizontal position so that the
wine keeps the cork moistened. The room should be darkened, free from dirt, and
mechanical or sound vibrations (Smith and Milner, 1974).
The purposes of storage and ageing are:
• For the development of body, flavor and bouquet,
• To aid the clarification.
Ageing of wines improves the flavor and bouquet due to oxidation and formation of
esters. These esters of higher acids formed during ageing give the ultimate pleasing
bouquet to well aged wine. Aged wine may be polished by filtration to give a clear, bright
appearance prior to bottling (Desrosier, 1982). The period of ageing depends upon quality
of wine. For example- dry wines are aged for 2 years, and fine wines for 5 years.

34
2.21 Wine made from different raw materials
Wine can be prepared from different raw materials. It can be made from different fruits
(grapes, apple, pears, bael, guava, banana, pineapple, pumpkins, etc.) and roots (ginger,
potato, calocassia, etc.). Many researchers have prepared wines from different raw
materials in CCT, Hattisar, Dharan. Dhakal, (1988) prepared wines from ginger and banana
having varied recipes fermented by yeast isolated from murcha. TSS and pH were
optimized for banana and ginger wines. Banana wine was found best having 17o
Brix TSS
and 4.5 pH. Similarly, ginger wine having 22o
Brix and 5pH was found best. The alcohol
content of ginger and banana wines was found to be 7.06% and 8.39% (v/v) respectively.
He found that 17-20% sugar concentration, 100-200 p.p.m. SO2, 25-30o
C temperature and
4.5-5pH were suitable for appreciable starter activity.
Shakya, (2002) prepared bael wines from bael pulps obtained by hot and cold extractions.
The bael wine prepared from hot extracted pulp was found to be better than the cold
extracted. Bael wine from mash of 25% pulp content was the best. Fining agents tannin and
gelatin produced exceptional clarity. The bael wine contained 11%(v/v) alcohol, 0.12%
volatile acidity, 0.49% fixed acidity, 9.5g/100L methanol, 225 mg/L esters, 280 mg/L
aldehydes and 193 g/100L total higher alcohol.
Gubhaju, (2006) prepared wine from Rhododendron flower using wine yeast. Effect of
fresh and dried flower on quality of wine was studied. She found that use of raisin and
brown sugar did not improve the quality of wine. TSS of 20o
Brix and pH of 4.5 were found
optimum for the preparation of Rhododendron wine using dry flower and S. cerevisiae.
Average alcohol content and esters of the prepared wine were found to be 11.03% (v/v)
and 3.81 mg/L respectively.
Dhakal, (2007) prepared wine from palm sap using baker’s yeast. Wine made from mash
with 4.5 pH and 20o
Brix was found to be most acceptable. Total solids (%m/v), sp. gr. (at
25o
C), alcohol content (%m/v) and ash content (%m/v) were found to be 0.13, 0.9529, 36.5
and 0.005 respectively. Similarly, total aldehydes (as g acetaldehyde), esters (as g ethyl
acetate), fusel oil (as g amyl alcohol), total acidity (as g lactic acid), volatile acidity (as g
acetic acid) and fixed acidity (as g lactic acid) were found to be 0.525, 44.1, 84.46, 281,
162 and 37.47 per 100 L of ethanol respectively.

35
2.22 Fining agent and its types
The material which is used to achieve clarity of wine is called fining agent. The fining
agent has several adsorption sites on each head or molecule and a number of solute
molecules are either adsorbed to its surface or exchanged into its inferior. Several of the
agents currently in use (such as the proteins and the gums) are colloidal in nature and as the
adsorption occur, resulting in precipitation of the solute/agent complex from the solution.
The amount of solute removed by a certain addition of an agent will depend on the
solute/agent pair as well as the concentration of the solute in the wine and the quantity of
the agent added. The fining agents can be classified into the following groups:
2.22.1 The Proteins
The purpose of adding a protein preparation to wine is to soften or reduce the wine’s
astringency or reduce its color by the adoption and precipitation of polymeric phenols and
tannins. Although it is rarely practiced today, white wines can be clarified by adding a
protein followed by tannin due to the co-precipitation that occurs. All of these proteins
come from natural sources usually in a partially purified form. The four most commonly
used proteins for wine precipitation are casein, gelatin, albumin, and isinglass. Their
properties are summarized in Table 2.4.

36
Table 2.4 Typical ranges of application of fining agents.
Agent
Common Range of Application (mg/L)
White Table Wine Red Table Wine
Casein 60 to 120 60 to 240
Albumin N/A 30 to 240
Isinglass 10 to120 30 to 240
Gelatin 15 to 120 30 to 240
Bentonite (Na form) 120 to 720 N/A
Silica Sol 40 to 200 40 to 200
PVPP 120 to 240 120 to 480
Agar/ Alginate 120 to 480 120 to 480
Activated Carbon 120 to 600 120 to 480
(Source: Boulton et al., 1997)
2.22.2 The Earths
There are a number of clays: silica, alumina matrix with exchangeable cations, bentonite
etc. The clays (silica, alumina matrix) have been considered as alternatives to bentonite and
these include kaolin, Spanish earth. They generally have a lower adsorption capacity and
therefore are not preferred in winemaking applications.
2.22.2.1 Bentonite and its properties
Bentonite is widely used for the adsorption of proteinaceous material from wines.
Bentonite was originally introduced as a means of clarifying wines and vinegars (Saywell,
1934A.B) and its application to inducing heat stability in white wines came several years
later. Bentonites are mined from several areas of world and come in different levels of
purity, particle size, adsorption and swelling capacity. Bentonite is natural clay that is
classified as a montmorillonite, with a general composition of the form: Mg, Ca, Na,
Al2O3.5SiO2.nH2O (Siddiqui, 1968). The source of the bentonite influences its properties
slightly and the main difference lie in the proportion of Mg++, Ca++, and Na+ in the
lattice. Bentonite has a structure which expands after contact with water and preparations
have optimum adsorption after two days of soaking. The limited cation exchange capacity

37
poses particular problems with the removal of negatively charged and neutral protein
fractions from wines. Bentonite is essentially inert with respect to the phenolic components
in wine except for cationic anthocyanins. There is little effect of temperature on the
adsorption (Jacob, 1968; Blade and Boulton, 1988). Bentonite may indirectly bind phenols
that have complexed with proteins. Bentonite may affect red wine color by binding with
positively-charged anthocyanin monomers and may result in color decrease depending
upon the age of the wine.
Bentonite may also remove more color in younger wines because of the greater action on
the colloidally colored material found in the younger wines (Bergeret, 1963). Addition of
bentonite to red wines at levels of 6 to 12 g/hL (0.5 to 1 lb/1000 gal) improves membrane
filterability due to reduction in colloidally suspended particles. Bentonite fining of juice
may remove peptides and some amino acids, potentially affecting rate and completion of
fermentation. Bentonite fining is known to indirectly prevent or impede formation of
copper, and possibly iron casse, this is probably due to removal or reduction in levels of
proteins and peptides known to be involved in the formation of haze and precipitate.
2.22.2.2 Preparation of bentonite
Preparation of bentonite greatly impacts its activity toward proteins. In solution, bentonite
swells to many times its dehydrated dimensions. Its activity is much like that of a
multiplateted, ong-chain, linear, negatively-charged molecule (Singleton, 1967). During
the hydration phase, charged platelets repel each other and begin to separate. Water
molecules partially neutralize and separate exposed surfaces, exposing a large matrix of
reactive surface. The presence of water molecules within the network prevents flocculation
and precipitation. The water used in hydration phase should have a low mineral content.
Dissolved metal cations present in slurry water preferentially replace sodium ions on the
clay surface and detrimentally affect the hydration, viscosity, and binding capacity of the
bentonite (American Colloid Co.). Typically, the bentonite-to-water ratio for slurries is 5-
6% (w/v). Heating non-agglomerated bentonite allows the platelets to fully separate and
slurry resembles a gel. Bentonite additions, especially those exceeding 48g/hL (4 lbs/1,000
gal), may strip wine flavor, body, and in the case of young red wines, significant color.
Further, it may impart an earthy character to the wine. Some winemakers choose to ferment
settled juice in contact with benttonite to aid protein stability and to eliminate or reduce the

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