Wine Production - Dr. S. Sivasankara Narayani

1. Y5E02 BIOPROCESS
TECHNOLOGY – Unit IV –
Wine Production
Dr. S. SIVASANKARA NARAYANI
ASSISTANT PROFESSOR
DEPARTMENT OF MICROBIOLOGY
AYYA NADAR JANAKI AMMAL COLLEGE
SIVAKASI

2. Wine
• Wine is the product of grapes which can be obtained after alcoholic fermentation by yeast.
• Technically it is the transformation of sugars of grapes by yeast under anaerobic conditions into carbon dioxide, ethanol and
some by products.
• Wine can also be produced by the fermentation of the fruit juices, honey and berries
25-08-2020Dr.SS

3. History and Origin
• Winemaking probably began as one of the earliest of human enterprises (8000-3000 B.C.).
• The wine grape was domesticated by at least 4000 B.C.
• Wine was used for Egyptian worship ceremonies.
• Wine only became a popular beverage about 2000- 1000 B.C. in Greece.
• About 600 B.C., wine growing reached France. Wine grapes were introduced early into the United States.
• The Spanish introduced grapes into California in the 1700's.
•
25-08-2020Dr.SS

4. Steps
• Viticulture
• Harvesting
• Stemming/crushing
• Fermentation
• Draining
• Pressing
• Mixing
• Clarification
• Aging
• Bottling
25-08-2020Dr.SS

5. 25-08-2020Dr.SS

6. Viticulture
• Factors which inflence grape’s flavor:
• climate of the vineyard’s region
• drainage around the vines
• humidity of the region
• sun exposure.
• soil quality
25-08-2020Dr.SS

7. Harvesting
• Grappes are picked up by hand or mechanically
• Descision of harvest informed by level of sugar and acid
• weather forecasts
• Harvest There are over 4000 varieties of grapes used in the production
of wine.
• Grapes are usually harvested from early September to the beginning of
November.
25-08-2020Dr.SS

8. It starts in the vine yard at harvest
• It is important to wait until the grapes reach the proper maturity for the variety of grape & style of wine being made.
• As the grapes ripen, the sugar level increases and the acidity decreases.
• The sugar level is measured in units of "Brix"; wine grapes are usually harvested at a Brix of 22 to 28.
• Ripening will depend on many factors, such as the temperature, amount of sun and rainfall, availability of nutrients.
• The grapes can be harvested manually or by mechanical pickers. Manually picked grapes are typically higher quality.
25-08-2020Dr.SS

9. Grape Selection/Processing
Grapes must be tested with 50-75 ppm of free sulfur dioxide.
Sulfating is done to emove unwanted bacteria before the next step of the process.
Equipment must also be sanitized.
This is usually done with an based caustic solution, water, and then a anti-bacterial sulfite solution. Finally another water rinse.
25-08-2020Dr.SS

10. Stemming/Crushing
• Stemming is the separation of the stems and grapes (which are sends to the press)
• Crushing: A horizontal press squeezes the broken grapes, separating the fresh juice (must) from the skins (marc) After
crushing starts the fermentation process.
25-08-2020Dr.SS

11. 25-08-2020Dr.SS

12. After harvesting
• The grapes are transported to the winery where they undergo de stemming and crushing.
• There are a variety of processes that are used to produce the juice, which is called "must".
• The sugar in the wine is used by the yeast to produce ethyl alcohol and carbon dioxide gas, thus making wine.
• The type of yeast can affect the qualities of the wine as will the other compounds in the wine - some naturally occurring and some
that are byproducts of the winemaking process.
25-08-2020Dr.SS

13. Fermentation
• sugar and acids that naturally react with wild yeasts
• Vineyard adding their own yeasts
• fermentation can take from 10 to 30 days to convert
natural sugar to alcohol.
25-08-2020Dr.SS

14. Fermentation and Aging
• After crushing and pressing the must is transferred to large, refrigerated stainless steel tanks where it is fermented to produce wine.
• Once fermentation is complete, the wine can be transferred to oak barrels for aging for 6 tou months. But, not all wine is oak aged.
• The barrels are usually made from either French or American Oak, which give differing qualities to the wine.
• Some wine is aged in old barrels and some in new to produce different characteristics, as well.
• The wine maker will then blend the various lots twine to produce a finished wine ready for bottling.
25-08-2020Dr.SS

15. Principle Fermentation process
• C6H1206 + yeast ----2C2H40H + 2C02
• The alcohol solution that results from fermentation > contains about 12%-15 0 ethanol.
• This correlates to the conditions that yeast cells can survive in, higher concentrations of ethanol will kill the yeast.
• For every gram of sugar that is converted about a half gram of alcohol is produced.
• To achieve 12% alcohol concentration, starting material must contain about 24% sugars
25-08-2020Dr.SS

16. Malo-lactic fermentation (secondary fermentation)
• Malic acid is converted into lactic acid and carbon dioxide
• Changes the flavor of the wine from crisp to creamy buttery as well as reducing the amount acidity (increases pH from .3-.5 units)
This can be introduced or happen naturally — and monitored by testing with paper chromatograpy.
• Controlling the pH (best around 3.0-3.5) High pH results in less flavor production in the wine
• To lower pH, tartaric acid is added at the beginning of the fermentation process.
• Oxidation Reactions Acetobactor bacteria will react with the oxygen to convert the wine into vinegar
25-08-2020Dr.SS

17. Cont…
• During fermentation the most harmful bacteria that can grow O is of the genus Acetobacter.
• However, this bacteria is sensitive to the free sulfur dioxide, which is why cleaning process is important.
• Burnt match smell S02 levels are greater than 40 ppm Overly sweet wine Fermentation can be restarted to convert the residual
sugar into alcohol.
25-08-2020Dr.SS

18. Draining
• Liquid wine is drained from the vat without being pressed and go into barrels
(free-run wine). The remaining pulp retains about 20% of the wine.
25-08-2020Dr.SS

19. Pressing and Mixing
• The remaing pulp, after draining, is pressed to squeeze out the press wine.
• Mixing- The free-run wine and press wine, always from the same source, are mixedtogether in appropriate ratios to obtain the
desired balance.
25-08-2020Dr.SS

20. 8. Clarification
• Stabilisation of fermentation.
• Remaining solids are removed.
• Clarification done in numerous ways:
1. Fining
2. Filtration
3. Siphoning the liquid off the top of the fermenting vats after the
solids have settled to the bottom
4. Floatation
25-08-2020Dr.SS

21. Aging
• The final stage in vinification is aging the wine.
• At this point, the clarified wine is transferred into either
wooden barrels or metal vats in which the wine is allowed
to further mature and develop flavors.
25-08-2020Dr.SS

22. Bottling
• A dose of sulfite is added to help preserve the wine and
prevent unwanted fermentation in the bottle.
• The wine bottles then are traditionally sealed with a cork
25-08-2020Dr.SS

23. Bottling and Cellaring
• After the wine is complete it is transferred to bottles.
• Most wine is cons med within three years of bottling.
• But some fine wines gain added flavor and bouquet with
time in the bottle if it is stored at 50 to 60 F.
• But, humidity is also important so that the corks do not dry
out, which spoils the wine
25-08-2020Dr.SS

24. White wine
• vvine When processing grapes for White wine, after the cleaning process they are immediately pressed and the juice is sent to
the tanks.
• Fermentation temperature is usually about 15-180C
• Sweet wine are made by leaving some residual sugar after fermentation
• This is done by: Harvesting later Freezing the grapes to increase the sugar concentration Killing the yeast before fermentation
is complete
25-08-2020Dr.SS

25. Red wine
• Red wine Grapes are us ally crushed with all parts together and they O then go straight to fermentation
• The skin and seeds are important to pass on tannins and the bitter taste unique to red wine — this mixture is called "must”.
• Fermentation process is usually quicker for red wines
• This is because red wines can be fermented at a higher temperature
due to the nutrients it contain Fermentation temperature is usually 22-250C
25-08-2020Dr.SS

26. Cont…
• After the must is transferred to the fermentation tanks a > cap" is formed hich prevents air
• The cap is created b the solids that are pushed to the top due to the carbon dioxide
• This cap is kept in contact with the juice as much as possible in an effort to retain the color
• This is done by punching the cap down manually or by pumping the cap over mechanically
twice day
25-08-2020Dr.SS

27. Cont..
• Once the juice has been transferred to the fermentation tanks,
• the yeast is added and the oxygen is removed.
• By removing the oxygen from the tanks, the oxidation process is halted, which helps prevent any bacteria growth.
• Yeast Saccharomyces cerevisiae is the species of yeast used in the fermentation process.
• This yeast species has been acclimated to the effects of the free sulfur dioxide.
• Other species of yeast are intially present on the grape however are killed in the cleaning process
25-08-2020Dr.SS

28. Different types Of wine
• White Wine
• Red Wine
• Blush Wine
• Champagne (Sparking) Wine
• Fortified Wine
25-08-2020Dr.SS

29. Is wine good for you?
• Studies ha been done to show that wine drinkers are less > prone to heart disease, cancer and other diseases.
• This could be a result of the antioxidant resveratrol which may reduce cholesterol and the risk of Alzheimer's disease.
• However this antioxidant can also be found in other foods, avoiding the harmful effect of alcohol.
• The study of wine is becoming so popular that now a Bachelor of Science degree in oenology is available
25-08-2020Dr.SS

30. 25-08-2020Dr.SS

31. 25-08-2020Dr.SS

32. 25-08-2020Dr.SS

33. 25-08-2020Dr.SS

34. Clarification
25-08-2020Dr.SS
sivasan91@gmail.com
sivasan_sf549@anjaconline.org

35. Questions to think
• What are the steps involved in the wine production?
• What is clarification?
• What is must?
• Role of sodium sulfite?
• Pointout the use of wine
• What is malolactic fermentation?
• Veticulture
• Term refer to the study of oenology
25-08-2020Dr.SS

36. 25-08-2020Dr.SS