Sweet Wine Production
Botrytis cinerea is a fungus that saps moisture from the grapes, leaving them with a higher concentration of sugar and acidity. Welcomed and sometimes even encouraged in the vineyard, it is a scourge to other fruits. It is most famously used to make Sauternes, and Chateau d’Yquem is the best producer. Several producers in California also use this Sweet Wine Production process to make impressive Botrytis cinerea wines.
If grapes are left on the vine past the normal harvest time, they will develop more concentrated sugars and flavors. Late harvest grapes have too much sugar to be entirely converted by yeast to alcohol. Basically, the alcohol rises to a level that makes the yeast inactive, and the remaining residual sugar makes these wines sweet.
Passito is made with grapes that have been semi-dried and turned into raisins. Passito has a significant amount of residual sugar and very concentrated flavors. It has traditionally been made in Tuscany and Umbria, where it is highly valued. Tuscany is also the home of this Sweet Wine Production process.
Some quality sweet wines are made by adding some unfermented grapes juice to a fermented wine. In Germany, the addition of this juice is called sussreserve or “sweet reserve.” The sugar in the juice remains unfermented, making a sweet wine.
One method of Sweet Wine Production is to artificially stop the fermentation process before all of the sugar has been converted into alcohol by yeast. This is typically used to make off dry, floral white wines. Popular varietals used for this method include Gewurztraminer, Chenin Blanc, and Riesling.
> Related Articles