OBTAINING MORE ALCOHOL

 While dinner wines should range between 10 and 12% alcohol, some winemakers would like a higher alcohol content wine such as sherry. This can be accomplished by a slow "feeding the yeast" technique. This allows the yeast to slowly get used to the high alcohol content. A must of S. G. 1.080 is made up and fermented down to 1.000 - 1.005. At this point, while it is still fermenting, two ounces of sugar are added and the fermentation allowed to proceed until the S.G. is back down to 1.000 - 1.005 when another two ounces of sugar is added. This process is repeated until the fermentation stops or enough sugar is added to give the desired alcohol content. (See tables for ounces of sugar per gallon vs. potential alcohol.)

For example, a gallon of must with a specific gravity of 1.080 contains 26.1 ounces of sugar, per gallon. If four additions of two ounces of sugar were made, the total amount of sugar added was 34 ounces per gallon. Consulting the table we see that this corresponds to 14.1% alcohol. Using this method, alcohol contents of up to 17 - 18% can be achieved but only under the proper conditions.

Alcohol contents above 10% greatly inhibit yeast growth. Therefore the yeast should be well fed with nutrients. A species of yeast that is more tolerant to alcohol can be used such as Port, Sherry, Tokay or Sauternes. Even so, don't be surprised if the process takes more than six months.

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