Botrytis cinerea is a
fungus that affects many wine grapes and causes them to shrivel into moldy raisins. The fungus responds to the humidity and warmth in the climate and attacks the grapes. As the mold penetrates the skin its spores begin to
germinate, causing the water inside to evaporate and the grape to dehydrate. With the absence of water, the
sugar becomes more concentrated and the botrytis begins to alter the acidity within the grape. Typically botrytis infection begins to take place in late September and can last till late October. In some years
desiccation may occur leaving tiny amount of sweet liquor like juice within the grape. The infection rate of botrytis is sporadic with vines and bunches achieving full rottenness at different times. This requires
harvest workers to go through the vineyards several times between October and November to hand-pick the full rotted grapes. In some occasions, the usable grapes from a single vine may only produce enough juice for a single glass.
Sauternes Sauternes, such as
Château d'Yquem, are produced in the
Sauternes region (including
Barsac) south of
Bordeaux. They are made from botrytis infected
Semillon and
Sauvignon blanc grapes. Semillon is preferred due to the grape's thin skin and susceptibility to the botrytis which gives the grape a high
sugar content. These wines are noted for the balance that complements the honeyed sweetness.
Tokaji/Tokaj/Tokajské Tokaji wines are produced in the
Tokaj regions of
Hungary and
Slovakia. Wine has been made in these regions since as early as 1650, before the botrytized wines of Sauternes and the
Rheingau were produced. The
Furmint, Yellow
Muscat, and
Hárslevelű/
Lipovina grapes are the primary grapes used in this wine. In a manner similar to
Sherry, the wine is aged in partially filled barrels with a film of yeast on top and stored underground in
wine caverns. == German late harvest wines ==