Wine & spirits: The pleasures of sugar-rich wines
Grapes gathered at the normal harvest time and processed in the usual manner generally yield dry wines. With sweet wines, grapes may be harvested late, partially dried in the sun, naturally or artificially frozen, fortified with brandy or naturally withered by a unique mould. Each technique has a different effect on the finished wine.
The most common method is to leave the grapes on the vine well past the normal harvest date. They continue to ripen, developing extra sweetness and flavour. German Spätlese and Auslese are the best known late-harvest wines, but many others are produced similarly.
In Italy and Greece, ripe grapes are air-dried on racks or mats for weeks or months. They acquire a raisin-like flavour, yielding rich, sweet, strong and luscious wines.
Conversely, grapes can be left on the vine until the first deep-freeze. In Canada, we're most familiar with icewine -- frozen grapes are gently crushed, separating a small amount of superconcentrated juice from a lot of frozen ice crystals. Icewine has a perfect sugar/acid balance with strong fruit flavours, intense sweetness and refreshing acidity, and is one of the richest wines in the world.
Fortification is one of the oldest ways to make sweet wine. Midway through fermentation, alcohol is added in order to shock the yeast. As a result, any remaining sugar can't be converted to alcohol, so the wine remains sweet. Sherry, Madeira and port are all produced by fortification with unique grape varieties and traditional methods of aging, giving each its distinctive style.
If weather conditions are right, nature makes its own sweet wine when Botrytis cinerea, a natural mould, sends tiny root follicles through pores in the grape skin, sucking out water and shrivelling the grapes. The resulting wine, which is rare and expensive, has an ethereal crème brûlée and dried fruit bouquet.