Fermentation, barrel

Although it is sometimes encouraged in white wines, particularly barrel-fermented Chardonnay, this fermentation tends to lower fmitiness and be considered undesirable in other white wines unless acidity is too high. This is also tme for pink and light red wines. If it occurs after bottling, a gassy, cloudy wine results. In such wines, it can be avoided by careful attention to clarification or filtration sufficient to remove the bacteria, by adding SO2 at appropriate intervals as an inhibitor, or by pasteurization. 

Maturation regimes vary from as tittle change as possible in many white and pink wines (stainless steel tanks, cool storage, minimum time) to considerable modification in red table and a few white table wines. Fermentation and storage in fairly new 200-L barrels for about 6 mo is not uncommon for Chardoimay and white Burgundy wines. Many robust red table wines such as those from Cabernet Sauvignon grapes are often stored similarly, after fermentation and initial clarification, for up to about 3 yr in such barrels. 

The most widely available yeast biomass is a by-product of the brewing industry, where the multiplication of yeast during brewing results in a surplus of ceUs. Eor every barrel (117 L) of beer brewed, 0.2—0.3 kg of yeast soHds may be recovered. In the U.S., a substantial fraction is recovered and made available about 40 x 10 kg of brewers yeast aimually. The yeast is recovered from beer by centrifuging and dried on roUer dmms or spray dryers and sold as animal feed or a pet-food supplement. It can be debittered by alkaline extraction to remove the bitter hop residues, and is then sold mainly by the health-food industry. It is available as tablets, powder, or flakes and is often fortified with additional vitamins. Distillers yeast caimot be readily separated from the fermented mash and the mixture is sold as an animal feed supplement. 

Whiskey. Whiskey refers to any alcohohc distiUate made from a fermented grain mash at less than 190° proof (95%) in such a manner that it possesses the taste, aroma, and characteristics generaUy attributed to whiskey. It is matured in new or used charred oak barrels. Whiskey can be further delineated by the cereal grains used and the maturation time and blending, if any. 

Bourbon. Bourbon, and also rye, wheat, malt, and rye malt whiskeys, are made from a fermented mash not less than 51% com, rye, wheat, malt, or rye malt, respectively. They are distiUed at not over 160° proof and matured at not more than 125° proof in new charred oak barrels and bottled at not less than 80° proof. If stored for less than four years, it must be declared on the label. 

Corn Whiskey. Com whiskey must be distiUed from a fermentable mash that contains at least 80% com and at not over 160° proof. It is usuaUy matured in new uncharred oak barrels or used oak barrels and bottled at not more than 125° proof. 

Brandy. Brandy is a distikate from fermented juice, mash, fmit wine, or fmit residues. It is distiked at less than 190° proof in such a manner as to produce the taste, aroma, and characteristics generaky attributed to brandy. Fmit brandy is distiked solely from the fermented juice or mash of whole, ripe fmit or from standard grape, citms, or other fmit wine. Brandy distiked exclusively from one variety of fmit must be so designated, except grape brandy which can be identified by the term brandy. Brandy must be matured a minimum of two years in oak barrels, otherwise it must be labeled immature. 

Brewing Austenitic steels are used in fermentation vessels, storage tanks and attemperators, in yeast processing, and for transport tanks and barrels. 

After the song, Thomas stood and walked away from the table where his father lay flat as a paper plate. He walked outside and cried. Not because he needed to be alone not because he was afraid to cry in front of women. He just wanted his tears to be individual, not tribal. (1°) Those tribal tears collected and fermented in huge BIA [Bureau of Indian Affairs] barrels. Then the BIA poured those tears into beer and Pepsi cans and distributed them back onto the reservation. Thomas wanted his tears to be selfish and fresh. 

Ortega-Heras, M., Rivero-Perez, M. D., Perez-Magarino, S., Gonzalez-Huerta, C., and Gon-zalez-Sanjose, M. L. (2008). Changes in the volatile composition of red wines during aging in oak barrels due to microoxygenation treatment applied before malolactic fermentation. 

Full-bodied mms are allowed to ferment from 12 to 20 days, often relying on natural or wild fermentation in which the mash is inoculated by the yeast present in the air and starting materials. These mms are twice-distilled in pot stills to 140—160° proof. Full-bodied mms are often aged from five to seven years in oak barrels. Caramel color can also be added to give them a darker color. They are produced in Jamaica, Barbados, Martinique, Trinidad, and Guyana. 

Chemical Analysis. It is suggested that a set procedure be established for running specific analyses according to a specific timetable. For example, a visual and taste inspection of all wines every two weeks (two months for wines in barrels), malic and lactic acid analyses at weekly intervals during the malo-lactic secondary fermentation, and S02 and color analyses of white wines at least every two weeks until the wine is bottled. Basic analyses to monitor are V.A., S02, alcohol, pH, and T.A. 

Dehydrogenases often act primarily to reduce a carbonyl compound rather than to dehydrogenate an alcohol. These enzymes may still be called dehydrogenases. For example, in the lactic acid fermentation lactate is formed by reduction of pyruvate but we still call the enzyme lactate dehydrogenase. In our bodies this enzyme functions in both directions. However, some enzymes that act mainly in the direction of reduction are called reductases. An example is aldose reductase, a member of a family of aldo-keto reductases71 73 which have (a / P)8-barrel structures.74 76... 

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