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Topic: TRADITIONAL METHODS of ALCOHOL PRODUCTION
ALCOHOL
→ Alcohol is the most commonly used and abused drug among youth in the United States, more than
tobacco and illicit drugs, and is responsible for more than 4,300 annual deaths among underage youth.
→ Humans have been drinking alcohol for thousands of years. Alcohol is both a chemical and a
psychoactive drug.
→ In chemistry, an alcohol exists when a hydroxyl group, a pair of oxygen and hydrogen atoms, replaces
the hydrogen atom in a hydrocarbon. Alcohols bind with other atoms to create secondary alcohols. These
secondary alcohols are the three types of alcohol that humans use every day: methanol, isopropanol, and
ethanol.
ALCOHOLIC BEVERAGES:
There are two categories of alcoholic beverages:
1-Distilled Drink. 2-Undistilled Drink.
1- Distillated Drinks:
→ Distillation is a process which follows fermentation. The process converts a fermented substance into
one with an even higher concentration of alcohol.
→ Distillation concentrates alcohol by separating it from the water and other components of a fermented
substance.
→ Example:
→ Liquors and spirits are distilled alcoholic beverages. They contain more alcohol by volume than
undistilled drinks. In general, a distilled alcoholic beverage will have a higher alcohol proof.
2- Undistilled Drinks:
→ Undistilled drinks are also called fermented drinks.
→ “Fermentation is the process by which bacteria or yeast chemically converts sugar into ethanol.” Wine
and beer are both fermented, undistilled alcoholic beverages.
→ Wineries ferment grapes to make wine.
→ Breweries ferment barley, wheat, and other grains to make beer.
Traditional Method of Alcohol Production:
There are many different kinds of alcoholic drinks, and some of them contain more alcohol than others. The
types of alcoholic drinks with higher concentrations of alcohol are able to cause drunkenness and alcohol
poisoning more quickly and in smaller doses.
• Wine (Undistilled Drink)
• Beer (Undistilled Drink)
• Ethanol
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1- WINE PRODUCTION
Introduction:
➢ Wine may be defined as the usually fermented juice of a plant product (as a fruit) used as a beverage. In
many countries wines have from time immemorial been produced from all manner of plant materials and
not only from fruits.
➢ Wine making rely heavily on modern microbiology and biochemistry, traditional techniques and tried
and true manufacturing practices are still important, and in many cases, necessary to produce high quality
products.
History:
• The history of wine is nearly as old as the history of human civilization. The earliest writings discovered
on the walls of ancient caves and in buried artifacts contain images of wine and wine-making
instruments.
• Wine is also one of the oldest of all fermented products that has been commercialized, mass produced,
and studied. In fact, many of the early microbiologists and chemists were concerned with wine making
and wine science.
• Less than 150 years ago, when the very existence of microorganisms was still being debated, Pasteur
showed that not only did microorganisms exist, but that they were responsible for both production and
spoilage of wine.
Types of Wine:
There are the different types of wine are used in the market. These are;
- Sweet wines - Sparkling wines
- Fortified wines - Champagne
Wine Manufacturing Process:
Making wine, as far as the actual steps are concerned, looks to be a rather simple and straight forward process.
In reality, the process is far from easy, and each of these pre- fermentation, fermentation, and post-
fermentation steps must be carefully executed if high quality wine is to be consistently produced.
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Wine Making Methodology & Procedure:
Harvesting of Fruits:
❖ Appropriate variety of fruits and berries are harvested.
❖ Without fruit there would be no wine, and no fruit
other than grapes can produce annually a reliable
amount of sugar.
❖ Harvesting can be done mechanically or by hand.
❖ As mechanical harvesters can often be too tough on the
grapes and the vineyard.
❖ They must contain high amounts of fermentable
sugars.
❖ Grapes usually contain 5-25% total soluble sugar
(Total soluble sugar).
Crushing & Extraction:
❖ Thus, obtained fruits are crushed and extracted
mechanically.
❖ This process releases juice and a little bit pigment.
❖ The whole mass is known as Must.
❖ For white wine preparation, the skin is removed. The
harvested fruits are de-steamed for white wine
preparation which is not required for red wine
preparation.
❖ In case of red wine, the steam gives vegetable aroma
due to presence of 2 methoxy-3-isopropyl pyrazine.
❖ Color is also extracted from steam.
❖ In case of red wine, the Must should be fermented.
Pressing:
❖ Mechanical pressing has also improved the quality and
longevity of wine, while reducing the winemaker's
need for preservatives.
❖ The skin of must is taken out and pressed in order to release juice and alcohol.
❖ The liquid is again transferred into tank.
❖ In case of white wine, pressing is carried out before fermentation.
❖ During pressing color of fruits and berries is extracted.
Heat & Cold Sterilization:
❖ In cold sterilization method, the fermented must is cooled to nearly freezing and kept for one to two
weeks.
❖ During this period, the crystals get separated or stirred in the wall of fermenter and clear liquid is
collected on secondary fermented tank.
❖ In heat stabilization technique, it is gently heated in between 50-60o
C for an hour and kept overnight.
❖ The proteins get decanted.
Primary Fermentation:
❖ During the fermentation, the content is mixed twice a day by punching the floating skin for proper
aeration.
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❖ It also helps in color extraction.
❖ This fermentation allows rapid multiplication of yeast cell as well as sugar fermentation to ethanol, when
the TSS is decreased nearly about 9-10% then primary fermentation is terminated.
Secondary Fermentation:
❖ During secondary fermentation, aroma is
developed.
❖ The aroma in wine is categorized into 3 types:
• Primary aroma ------> contributed by fruits
or berries
• Secondary aroma --------> developed during
secondary fermentation
• Tertiary aroma --------> developed during
bottled ageing
❖ The aroma compound may be volatile or non-
volatile.
❖ Before secondary fermentation malo-lactic fermentation occurs.
Laboratory Testing:
❖ After secondary fermentation, certain laboratory tests are conducted which includes bricks reading,
bricks pH, titrable acidity, residual sugars, free or available sulfur, total sulfur, volatile acidity and
alcohol percentage.
Clarification:
❖ Once fermentation is completed, the
clarification process begins. Winemakers
have the option of racking or siphoning
their wines from one tank or barrel to the
next.
❖ Filtering and fining may also be done at this
stage. Filtration can be done with
everything from a course filter that catches
only large solids to a sterile filter pad that
strips wine of all life.
❖ winemakers will add egg whites, clay, or
other compounds to wine that will help
precipitate dead yeast cells and other solids
out of a wine. These substances adhere to
the unwanted solids and force them to the
bottom of the tank.
❖ The clarified wine is then racked into
another vessel, where it is ready for bottling or further aging.
Blending & Fining:
❖ It is the most crucial to produce good quality of wine giving special taste and aroma.
❖ In blending process, spices, extracts of aromatic plants, essential oils, fruit juices and other things are
added in appropriate proportion.
❖ Blending is kept trade secret in winery.
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❖ In fining process, tannins and microscopic particles are removed in order to make clear wine.
❖ Finally, wine is clarified in order to remove pectin which is achieved with the use of pectinase
enzyme.
Aging:
❖ Aging actually begins just after fermentation. Thus, aging occurs when the wine is racked, as well as
beyond. Aging conditions vary considerably.
❖ Some wines are aged for several years, whereas others are “aged” for only a few weeks. Some wines
are aged in expensive oak barrels, others in stainless steel, and yet others depend on bottle-aging, or a
combination of all of the above.
Preservation:
❖ Pasteurization technique and use of KMS
(Potassium metabisulphite) are mainly used for
preservation.
❖ It kills sugar utilizing micro-organisms.
Bottling:
❖ Finally, wine is aseptically filled in bottle and
bottle is corked, which is usually made with oak.
❖ Finally, the outside cork is sealed.
❖ The bottled wine can be directly consumed or
preserved.
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2- BEER PRODUCTION
Introduction:
→ Beer is the most popular alcoholic beverage worldwide. In fact, after water and tea, beer is the most
commonly-consumed drink in the world.
→ Beer is also most likely the oldest alcoholic drink in history. A standard beer, whether it be a lager or
an ale, has between 4% to 6% ABV, although some beers have higher or lower concentrations of
alcohol.
→ For example, “light beers” only have between 2% to 4% ABV while “malt liquors” have between 6%
to 8%.
→ In some countries beer is defined by law—as in Germany, where the standard ingredients, besides
water, are malt (kiln-dried germinated barely), hops, and yeast.
History:
• Before 6000 BCE, beer was made from barley in Sumer. Barley or partly germinated barley was
crushed, mixed with water, and dried into cakes.
• Brewing in the 21st century is a large-scale industry. Modern breweries use stainless-steel equipment
and computer-controlled automated operations, and they package beer in metal casks, glass bottles,
aluminum cans, and plastic containers.
• Beers are now exported worldwide and are produced under license in foreign countries.
Types of Beer:
- Beverages similar to beer are produced in Japan (sake, from rice).
- Mexico (pulque, from agave).
- In Africa, malted sorghum, millet, and maize (corm) are used to produce local beers.
Beer Making Methodology & Procedure:
Beer production involves malting, milling, mashing, extract separation, hop addition and boiling, removal of
hops and precipitates, cooling and aeration, fermentation, separation of yeast from young beer, aging,
maturing, and packaging.
Malting:
❖ Beer is produced from barley grains.
❖ Barley grains are first cleaned and then soaked in water for about 2 days. Then excess water is drained
away and the barley are incubated for 4-5 days to allow germination.
❖ The germination steps allow the formation of highly active α-amylase, β-amylase and proteases enzymes
as well as various flavor and color components.
Malt adjuncts:
❖ Barley contains considerable amount of protein. So, if only barley is used for beer production, the final
beer will be dark and unstable.
❖ Therefore, protein present in malt should be diluted by adding additional starch or sugary materials.
❖ Such sugary or starchy materials are called malt adjuncts and includes dextrose sugar syrup.
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Kilning:
❖ The germinated seed are then killed by slow heating at 80° This process is called kilning.
❖ Special malts are made by wetting and heating green malt in closed drums at high temperatures.
❖ The kilning temperature must not harm amylase enzyme. Furthermore, if kilning temperature is higher,
darker will be the beer produced.
Modernization
❖ Modern maltings can produce malt in four to five days, and technological improvements give precise
control over temperature, humidity, and use of heat.
Mailing:
❖ The dried barley grains are then crushed between rollers to produced coarse powder called grist
❖ For efficient extraction with water, malt must be milled. Early milling processes used stones driven
manually or by water or animal power, but modern brewing uses mechanically driven roller mills.
❖ The object is to retain the husk relatively intact while breaking up the brittle, modified starch into
particles
Mashing:
❖ Grist is mixed with warm water and the resulting materials is maintained at 65°C for about 1 hour.
❖ In doing so, starch is hydrolyzed by amylase enzyme to produce single sugar, maltose, dextrose etc.
similarly, protein is hydrolyzed by proteolytic enzymes into small fragments and amino acids.
❖ The degree of enzymatic hydrolysis is strongly depending on pH and temperature. β-amylase has
optimum activity at temperature 57-65°C whereas α-amylase has optimum activity at temperature 70-
75°
❖ The liquid obtained by mashing is called wort. The husks and other grains residue as well as precipitated
proteins are removed filtration.
Boiling of wort:
❖ The filtrate is then boiled with stirring for 2-3 hours and hop flowers are added at various interval during
boiling.
Reasons for boiling of wort:
o For extraction of hop flavor from hop flower.
o Boiling coagulates remaining protein and partially hydrolyze protein and help in removal of protein.
o Boiling inactivates enzymes that were active during mashing, otherwise causes caramelization of sugar.
o Boiling also sterilize and concentrate the wort.
Hops:
❖ Hops are dried female flower of hop plant Hamulus lupulus. Approximately one quarter pound of hop flower is
added per barrel of beer and up to 2 pound per barrel of ale.
Advantages of hop addition in beer are;
o Provide beer with its pungent and aromatic character.
o Provide tannin which helps in coagulation of remaining protein.
o Contains α-resin and β-resin which gives bitter flavor as well as preservative action against gram
Positive bacteria.
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o Contains pectin which is responsible for foam characteristic of beer.
Heating & Cooling:
❖ The kettle boil lasts 60 to 90 minutes, sterilizing the wort, evaporating undesirable aromas and
precipitating insoluble proteins.
❖ Clarified wort is cooled, formerly in shallow troughs or by trickling down an inclined cooled plate but
now in a plate heat exchanger.
❖ While cold water passes along the other side in the opposite direction. Oxygen is added at this stage, and
the cooled wort passes to fermentation vessels.
Fermentation:
❖ Beer production utilize strain of Saccharomyces carlsbergens and S. varum which are bottom yeast and
S. cerevisiae which is a top yeast.
❖ Yeast cells for inoculation are usually recover from previous fermentation tank by treatment with
phosphoric acid, tartaric acid or ammonium persulphate to reduce the pH and removed considerable
bacterial contamination.
❖ Fermentation is usually carried out at 3-4 °C but it may range from 3- 14° Fermentation usually completes
in 14 days.
❖ During fermentation yeast converts sugar mainly into ethanol and CO2 plus some amount of glycerol
and acetic acid.
❖ For fermentation open tank fermenter can be used however closed fermenter tank is preferred, so that
CO2 liberated during fermentation can be collected for later carbonation step.
❖ CO2 evolution is maximum by fifth day of fermentation, there is no evolution of CO2 by 7-9 days
because yeast cells become inactive and flocculate.
❖ Most beer contains 3.5-5% alcohol.
Finishing, Ageing, Maturation & Carbonation:
❖ The young and green beer is stored in vat at 0°C for several weeks to several months. During this period,
precipitation of protein, yeast, resin and other undesirable substances take place and beer become clear.
❖ Ester and other compounds are also produced during ageing which gives taste and aroma.
❖ After ageing, the beer is carbonated by carbon dioxide of 0.45-0.52%.
❖ The beer is then cooled, clarified, filtered and packed in bottles, barrels and cans.
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3- ETHANOL PRODUCTION
Introduction:
→ Ethanol (ethyl alcohol, EtOH) is a clear, colorless liquid with a characteristic, pleasant odour. Ethyl
alcohol is the intoxicating component in beer, wine and other alcoholic beverages.
→ Ethanol is a natural byproduct of plant fermentation and can be produced through the hydration of
ethylene.
→ In dilute aqueous solution, it has a somewhat sweet flavor, but in more concentrated solutions it has a
burning taste.
→ It is also being used as a biofuel in several countries across the world.
→ Large industrial plants are the primary sources of ethanol production, though some people have chosen
to produce their own ethanol.
→ Ethanol production from agricultural products has been in practice for more than 100 years.
→ Ethanol can be produced from many kinds of raw materials that contains starch, sugar or cellulose etc.
→ In general, there are three groups of raw materials from which ethanol can be produced:
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1) Beet, sugar cane, sweet sorghum and fruits
2) Starchy material such as corn, milo, wheat, rice, potatoes, cassava, sweet potatoes etc.
3) Cellulose materials like wood, used paper, crop residues etc.
→ Ethanol (or ethyl alcohol) is the type of alcohol that over two billion people drink every day. This type
of alcohol is produced by the fermentation of yeast, sugars, and starches.
→ For centuries, people have consumed ethanol-based drinks, such as beer and wine, to change the way
that they feel. However, ethanol also has harmful effects on the body.
→ The human liver can metabolize ethanol, but only in limited quantities.
→ Ethanol is toxic, so it damages the liver, the brain, and other organs over time. Ethanol also inhibits the
central nervous system, thereby impairing coordination and judgment.
History:
• In many parts of Canada, fields of corn or wheat are common sights. When you see these fields, you
might think of food. But these grains are not just for toast and corn flakes anymore. They also end
up in Canadians’ fuel tanks, in the form of ethanol.
Production of Ethanol by Using Corn:
Milling:
❖ Whole corn kernels are ground into a form of flour, or meal. The meal is mainly starch. A starch is
a carbohydrate made up of long chains of sugar molecules.
Liquefaction:
❖ Water is added to the meal to make ‘slurry.’ The slurry is heated to break the long starch molecules
into smaller pieces.
❖ The enzyme alpha-amylase is added to catalyze (or speed up) the breakdown of the starch
molecules.
❖ Saccharification:
❖ Starch molecule pieces are broken down into the simple sugar glucose. This reaction is catalyzed
by an enzyme called glucoamylase.
Fermentation:
❖ Single-celled microorganisms called yeast are added to the slurry. Fermentation is the biochemical
process that occurs when yeast break down glucose.
❖ Yeast gets energy from glucose. As a result, ethanol is produced.
Distillation & Dehydration:
❖ The product of the fermentation process is only 10-15% ethanol. It must be concentrated to become
pure (100%) ethanol. Ethanol has a lower boiling point than water.
❖ It is selectively evaporated and condensed in a process called distillation. This process produces
ethanol that is 95% pure. The remaining 5% of the mixture is water. The mixture is strained
and dehydrated to produce pure ethanol.
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Denaturation:
❖ A small amount of gasoline is added to fuel ethanol to make it undrinkable.
By-Products:
There are two main byproducts of corn ethanol production:
A. Carbon dioxide (CO2)
B. Distillers’ grains
A. Carbon Dioxide (CO2):
▪ CO2 is produced by yeast as a byproduct of the fermentation reaction. It is often released into the
atmosphere. But it can also be captured and used for other purposes.
For Example:
▪ Making carbonated beverages.
▪ Producing dry ice (frozen CO2) to use for cold storage.
▪ Supporting photosynthesis in vegetable greenhouses.
B. Distillers’ Grains:
▪ Distillers’ grains are the residue from the fermentation tanks. They contain all the non-fermentable
components of the corn kernels, plus the added yeast.
▪ Distillers’ grains are valuable as a high-protein ingredient in livestock feed.
Uses of Ethanol:
Household Products:
➢ Ethanol mixes easily with water and many organic compounds and makes an effective solvent for use in
paints, lacquers and varnish, as well as personal care and household cleaning products.
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Chemical Feed Stock:
➢ In the chemical industry, ethanol is an intermediate in many chemical processes because of its great reactivity. It
is thus a very important chemical feed stock.
Solvent Use:
➢ Ethanol is widely used in industry as a solvent for dyes, oils, waxes, explosives, cosmetic etc.
General Activity:
➢ Alcohol is used a disinfectant in hospital, for cleaning and lighting in the home and in the laboratory
second only to water as solvent.
Fuel:
➢ Ethanol is mixed with petrol or gasoline upto 10% and known as gasohol and used in automobile.
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