Late harvest wine in the sun to concentrate their sugar. Late harvest wine Late harvest wine is wine made from grapes left on the vine longer than usual. "Late harvest" is usually an indication of a sweet dessert wine, such as late harvest Riesling. Late harvest grapes are often more similar to raisins, but have been naturally dehydrated while on the vine. Botrytis cinerea, or "noble rot", is a mold that causes grapes to lose nearly all of their water content. Wines made from botrytis-affected grapes are generally very sweet. Botrytis cinerea is a fungus that affects many wine grapes and causes them
Phenolic content in wine grapes varies depending on the variety with Cabernet Sauvignon, Nebbiolo, Syrah and Tannat being 4 of the most tannic grape varieties. The reaction of tannins and anthocyanins with the phenolic compound catechins creates another class of tannins known as pigmented tannins which influence the color of red wine. Commercial preparations of tannins, known as "enological tannins", made from oak wood, grape seed and skin, plant gall, chestnut, quebracho, gambier and myrobalan fruits, can be added at different stages of the wine production to improve color durability. The tannins derived from oak influence are known as "hydrolysable tannins" being created from