MIC 303INDUSTRIAL AND ENVIRONMENTAL MICROBIOLOGY

INDUSTRIAL PRODUCTS FROM MICROBIAL

PROCESSES (WINES)

Alcoholic Beverages - Wines

WINESWinemaking procedure(s) differs at winemaker, winery, region, and country level.Many different techniques, recipes, outcomes.Made from fruits, typically grapes (contain sugar, can be directly used by yeast for fermentation) → malting process is unnecessary).If other fruits used, might be supplemented with other sugars to ensure enough alcohol produced.Wines produced by grapes are acidic due to high concentration of malic acid → Lactic acid bacteria sometimes added to convert malic acid to weaker lactic acid (malolactic fermentation process) → resulting in less acidic, better tasting wines.

Types of WinesRed Wine:

made from the pulp of the black grapes

the whole grapes including the skin is fermented → gives colour to wine.White wine

The skins of grapes was removed, only content of the grapes being fermented → giving a fruit characteristics to the wine produced.

Types of Wines

Sparkling Wine/ Fortified wine introduced by winemakers in the Champange region of

France. Addition of spirit, creating a second carbon dioxide

fermentation → giving the wine bubbles formation. Wine which spirit added during or after fermentation, usually

contain 20% alcohol (most common spirit used Brandy)→ Dry / Sweet Wine.

Sherry wine (Dry wine) Spirit added when the fermentation has ended. Contain low alcohol made from sundried sweetish, low acid Palermo grapes.

Port Wine (Sweet wine) spirit added during fermentation → residual sugar will

produced a sweet wine, present simple sugar. increase blood circulation in ladies.

Steps of wines production

Harvest.Crush.Must Additions.Fermentation(s).Pressing.

Settling/Racking. Wine produced will be stored at settling/

wooden vats. Wine start to cool. Precipitation of positive charge pulp protein

with negative charge tannins.

Filtering/Cold Stabilization.

Steps of wines production

Aging/Blending Very expensive wine Done in wood cask/ vast CO2 in the cask enter

cask wall porous cause condensation, polymerization, precipitation of tannins of red wine and lessening harshness

also cause acetaldehyde formation.

Bottling

Figure 28.9

Process of Making Red Wine

Alcoholic Beverages - BeerAle, beer and lager: Ale: Beer produced by top fermentation with S.cerevisiae. Lager: Beer made by bottom fermentation with

S.calsbergenesis.Raw material use grain starches fermented by yeast.Starch from grain must converted into glucose and maltose → yeast can ferment converted into ethanol and CO2.Malting: Germinating barley converts starch to maltose and glucose → allowed to sprout and then dried and ground → producing malt.This product, contain starch degrading enzymes (amylases) that convert cereal starches into carbohydrate.Light beers → selected yeast and to convert more starch to produce glucose and maltose → in fewer carbohydrates and more alcohol.

Types of Yeast

Products of grain starches fermented by yeast

Alcoholic Beverages – other types

Sake: The Japanese rice wine. use Aspergillus to convert the rice starche to sugar that

can be directly fermented without going malting process.

For distilled spirits, vodka, rum, whiskey: use carbohydrate from cereal grains, potatoes, and molasses then fermented into alcohol.