|MadSci Network: Agricultural Sciences|
Wines are fermented via yeast. The yeast metabolize the sugar of the grapes to ethanol. As the ethanol concentration increases, (sugar decreases) the yeast activity decreases. Eventually, (12-16%) the alcohol concentration becomes so great that the yeast can no longer metabolize. Wine makers can control the alcohol content of the wine by the sugar concentration of the grape slurry, temperature of fermentation etc. ALcoholic beveages with ethanol concentrations above about 16% are normally distilled or mixed with distilled spirts.
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