Wine Basics - Dessert Wines
Like sparkling wines, there are a variety of methods for making sweet wines. These vary from cheap and easy, to some of the most labour-intensive and expensive processes in the winemaking world. We are talking here about fully sweet wines, often drunk with desserts, though the French like to partner the finest foie-gras with a luscious Sauternes- perhaps the king of sweet wines.
Like so many aspects of winemaking, the discovery that grapes left on the vine until they rot can produce beautiful wines, was probably yet another accident.
Botrytis is a fungus which may attack grapes, usually in the cool of late autumn. It occurs in the early morning mists which form in vineyards sited near large bodies of water. The fungus wraps itself around the grapes and spores puncture the skin, drawing off water and leaving the grape shrivelled.
If left unchecked, botrytis will kill grapes and can be a big problem to vine growers. In some unique locations (Sauternes in France, parts of Germany and Austria for example) the vineyards are sited such that they also get maximum exposure to the sun.
In good years, the warmth of the sun as it rises kills off the fungus, leaving the grapes shrivelled and unsightly, but tasting delicious, full of the sugar and glycerine which was left behind.
Vineyards for botrytis wines are harvested by hand, so that only those individual grapes affected by the "noble rot" are selected. Often the same area will be picked over several times so that grapes can be picked in ideal condition. The wine is then made using the normal method for white wines, but the high sugar and glycerine content means that the wine is sweet, luscious and full-bodied. Because grapes high in natural acidity are used (sémillon, sauvignon blanc, riesling, gewürztraminer) the wine is not at all cloying. Though sweet, the best wines are balanced and full of subtle flavours that linger on the palate.
Botrytis wines are always expensive and often bought by the half bottle. With the unpredictability of the harvest and the labour-intensive methods used, it is perhaps easy to see where the money goes.
Other sweet wines and methods of production
Some other sweet wines are produced from grapes that are over-ripened, but not rotted. This can be done by simply leaving the grapes on the vine for longer than usual, or harvesting the grapes as normal but leaving them spread out to dry on mats so that they shrivel in the sun and air. One interesting, rare and expensive form of sweet wine is the ice-wine (in German, Eiswein) of Germany, Austria and Canada. Here the grapes are left on the vine into the dead of winter- often into the new year. On a suitably freezing cold night the grapes are harvested. Most of the water content of the grapes has turned to ice and this is expelled from the grapes leaving only the sugars and acids behind in the pulp. A wine is made from this, which is very luscious and sweet.
Another group of sweet wines are sweet because fermentation is stopped at a fairly low alcohol level. At that point, there is still plenty of natural sugar that has not been consumed by the yeast, so the resulting wine is naturally sweet. Fermentation is usually stopped by filtering out the yeasts, but in some wines the fermentation is stopped by adding spirit to the tank. This is the basis of the great sweet, fortified wines such as Port and Madeira, as we shall see in the next section.
The cheapest method of making a dessert wine is simply to add sugar. In the best cases this will be natural grape sugar, in the worst, sacks of cane sugar. Although these wines are sweet- and may please some palates- they are usually lacking in balancing acidity and interesting flavours.
Dessert wine tastes and styles
Dessert Wines have varying levels of sweetness and are often a golden yellow colour. Their taste is often described as honeyed, while toffee and caramel notes are common too. Many will display flavours of "white" fruits: peaches, pears, melon, etc.
Vermouth Here the overwhelming flavour comes not from the wine at all, but from the herbs used as flavouring agents.