Beverages :- Wine, Beer & Ethanol

A drink is a liquid intended for human consumption. In addition to their basic function of satisfying thirst, drinks play important roles in human culture. Common types of drinks include plain drinking water, milk, juice and soft drinks.

1. Beverages :- Wine, B eer & Ethanol HEENA KAUSAR DEPARTMENT OF MICROBIOLOGY

2. What is b everages Any potable liquid which is alcoholic and non alcoholic is known as “beverages” . It is a liquid intended for human consumption .

3. The large number of beverages may be classified as shown:

4. Alcoholic beverages An alcoholic beverages is a drink that typically contains 30 - 60% ethanol commonly known as alcohol. Alcoholic beverages are divided into 3 classes: Beer Wine Spirit (distilled beverages) They are legally consumed in most countries around the world. More than 100 countries have laws regulating their production , sale and consumption.

5. Fermantation process Fermantation is a metabolic process that converts sugar to acids, gases and /or alcohol. Sugar yeast Alcohol + CO 2 It is a process in which raw or waste material are convert into economically important product.

6. Wine Wine is an alcoholic beverage made from the fermentation of unmodified grape juice. The natural chemical balance of grapes They ferment without the addition of sugars, acids, enzymes or other nutrients. Yeast on the outside of grapes

7. Temperature is the most important factor in storing wine Optimum temperature: 50 to 55°F Acceptable temperature: 40 to 65°F Grape Varieties Wine is usually made from one or more varieties of the European species.

8. Pinot Noir Chardonnay

9. Merlot Vitis vinifera

10. Steps of wine production Harvesting Stemming/Crushing Fermentation Draining Pressing Mixing Clarification Aging Bottleing

11. Harvesting Descision of harvest informed by level of sugar and acid . Grapes are picked up by hand or mechanically.

12. 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.

13. Fermentation Sugar and acids that naturally react with wild yeasts Vineyard adding their own yeasts F ermentation can take from 10 to 30 days to convert natural sugar to alcohol. Wine fermentation tanks

14. 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.

15. Pressing The remaining pulp, after draining, is pressed to squeeze out the press wine . The press wine tends to be dark, harsh and is mixed with free-run wine to produce something decent. Grape pomace after pressing

16. Newer style equipment for pressing grapes

17. Mixing The free-run wine and press wine, always from the same source, are mixed together in appropriate ratios to obtain the desired balance.

18. Clarification Clarification is the step of stabilisation of fermentation. During clarification all remaining solids are removed from the fermented liquid. Clarification done in numerous ways: Running the liquid through coarse and fine filters S iphoning the liquid off the top of the fermenting vats after the solids have settled to the bottom

19. 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. If a winemaker chooses to age the wine in wooden casks, he will be allowing the wine to pick up flavors from the wood, adding greater depth to its flavors. While this can add body to some wines, keep in mind that the “woody” flavor isn’t suited to all types of wine, hence the use of metal vats.

20. Aging of wine in barrels

21. Bottleing The final step of wine production. 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, but now use synthetic corks and screwcaps, which are less subject to cork taint, are becoming increasingly popular.

22. Different Kinds of Wine Red or white wine Rosé wine Table wine Sparkling wines Dessert wine Fortified wine Cooking wine

23. Red wine Red wine is made from red (or black) grapes But its red color is bestowed by a process called maceration whereby the skin is left in contact with the juice during fermentation

24. White wine White wine can be made from any color of grape. As the skin is separated from the juice during fermentation.

25. Rose wine A white wine made from a very dark grape may appear pink, "rosé" or "blush".

26. Sparkling Wines Sparkling wines such as champagne, contained carbon dioxide which is produced naturally from fermentation.

27. Dessert wine Dessert wines range from slightly sweet (with less than 50 g/L of sugar) to incredibly sweet wines (with over 400 g/L of sugar).

28. Fortified Wine Fortified wines are often sweeter, and generally more alcoholic wines.

29. Beer Beer is an alcoholic beverage usually made from malted . Cereal grain (as barley), flavored with hops, and brewed by slow Fermentation.

30. What is beer made of? Malted Barley Hops Yeast Water Not required, but frequently found ingredient Starch adjuncts Corn and rice starches

31. Making Beer: a three step process Malting Brewing Fermentation

32. Malting In the preparation of malt , barley grains are soaked at 10 to 15.6 C , and germinated at 16 to 21 C for 5 to 7 days. Most of the sprout or germs are removed, and the malt remains.

33. Brewing process Mashing Fermenting Conditioning Filtering Packaging

34. Mashing Main ingredients such as water, malted barley and hops are put in a kettle and mix at 38 to 50 C. The mash is then boiled with hops in order to obtain wort . Hot wort is cooled down to fermenting temperature and then fermented using beer yeast.

35. Fermentation Fermentation process is takes place in closed fermentation tanks. Determined fermentation time and temperature must be observed. During fermentation, the highest amount of alcohol and carbon dioxide is produced. Following the fermentation, fresh beer is racked in conditioning. Fig : - Beer Fermentation

36. Conditioning With fermentation complete, the beer is removed from the yeast and pumped to a conditioning or bright tank. Where it is stored at near freezing temperatures that cause most of the remaining yeast to drop out of suspension. Once the beer is clear it is ready to filter and package.

37. Filtering and packaging Conditioned beer is filtered using a kieselguhr filter. The filtered, purified beer is stored in storage tanks. Filtering When beer is purified and filtered it is packaged in clean glass bottles and kegs. Packaging

38. Alcoholic fermentation (ethanol) Ethanol fermentation also called alcoholic fermentation, is a biological process which convert sugar such as glucose, fructose and sucrose into cellular energy, producing ethanol and CO 2. yeast Sugar Alcohol + CO 2 Because yeasts perform this conversion in the absence of oxygen. Alcoholic fermentation is considered an anaerobic process.

39. Usually the strain of yeast, Sacchromyces cerevisiae are employed for commercial production of ethyl alcohol. Generally, strains of S. cerevisiae are selected when starchy material, as well as saccharide material like mollasses are use as raw material.

40. One glucose molecule breaks down into two pyruvates . The energy from this exothermic reaction is used to bind inorganic phosphates to ADP and convert NAD+ to NADH. The two pyruvates are then broken down into two acetaldehydes and give off two CO2 as a waste product . The two acetaldehydes are then converted to two ethanol by using the H- ions from NADH

41. Raw materials A variety of corbohydrates available as waste product of agricultural industries are used for preparation of fermentation medium. On the basis of their chemical nature they may be group as- Saccharide material – molasses , whey, fruit juices Starchy material – potato starch, corn starch wheat flour. Cellulosic material – sulphite waste material and liquor

42. Fermentation condition Carbon source - Sugar concentration in the range of 10 to 18 % is found satisfactory. Ex- Cane molasses contains sucrose as a carbon source. Nitrogen source – Ammonium sulphate (0.15 gms / 2.5 gallons of molasses)is generally used.

43. pH – pH of the fermentation medium is adjusted to 4.8 – 5 . The higher value of pH increase the chance of contaimination , whereas the lower pH values inhibit the yield of ethyl alcohol. Temperature – Usually, the temp. range of 70-80 ͦ F is preferred. Time – Fermentation starts within a few hours after the addition of yeast, the process complete after 30-72 hrs in this stage it contains 6-8% of ethyl alcohol.

44. Yield – On an average of 0.4 gallons of ethyl alcohol is obtained from one gallon of molasses. About 90% of carbohydrates converted to alcohol.

45. Recovery – The fermented liquid is allowed to settle for a few hours and then distilled in analyser and rectifier columns to obtain rectifier spirit ethyl alcohol. The highest concentration that can be secured by fractional distillation is the constant boilling mixture which contains 95.6% ethyl alcohol and remaining 4.4% is water.

46. References Industrial microbiology by A. H. patel Pg. no. 146-148. Industrial microbiology by L. E. Casida , JR , chapter 18 anaerobic fermentation pg. no. 299- 303. Food microbiology 4 th edition by W. C. Frazier and D. C. Westhoff chapter 22 , food fermentations pg. no. 339-341.

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