How Is Wine Made Sweet?

While sweet wine is widely considered unfashionable, or is relegated to the dessert section of the menu, winemakers have been perfecting complex methods of creating sweet wine for centuries. Harvesting season, temperature and fermentation time are some of the factors that must be controlled in order to make wine sweet.

Drying Grapes

• Raisins are sweeter and less tart than fresh grapes because, when the fruit dries, the sugar grapes naturally contain becomes more concentrated. Some winemakers leave grapes in the sun to shrivel for a few days after harvesting them to concentrate their sugars before the fermentation process. Late autumn is the ideal time for this process, as grapes will have already matured to become sweet.

Ice Wine

• Ice wine, or eiswein in German, is made from grapes picked during a frost and then kept frozen. Freezing, like drying, concentrates the sugars in grapes. Also, because grapes for eiswein are picked in winter, much later than the usual August-October harvesting season, they've had time to ripen to extreme sweetness.

Noble Rot

• In autumn, a fungus called botrytis attacks grapes in some regions. This fungus incites a natural decomposition process called noble rot. Though botrytis was originally considered a problem by grape growers, it was discovered that the partially-rotted grapes resulting from a botrytis attack were perfect for making sweet wine. Many fine European dessert wines are made by harvesting recently botrytized, or nobly rotted, grapes.

Stopping Fermentation

• Grape liquors such as brandy can be added to fermenting wine to stop the fermentation process. This kills the sugar-consuming yeast, rendering a sweeter wine.