There is no simple definition of a dessert wine. In the UK, a dessert wine is considered to be any sweet wine drunk with a meal, as opposed to the white fortified wines (fino and amontillado sherry) drunk before the meal, and the red fortified wines (port and madeira) drunk after it. Thus, most fortified wines are regarded as distinct from dessert wines, but some of the less strong fortified white wines, such as Pedro Ximénez sherry and Muscat de Beaumes-de-Venise, are regarded as honorary dessert wines. In the United States, by contrast, a dessert wine is legally defined as any wine over 14% alcohol by volume, which includes all fortified wines – and is taxed more highly as a result. This dates back to a time when the US wine industry only made dessert wines by fortification, but such a classification is outdated now that modern yeast and viticulture can produce dry wines over 15% without fortification, yet German dessert wines can contain half that amount of alcohol.
A general rule is that the wine should be sweeter than the food it is served with – a perfectly ripe peach has been described as the ideal partner for many dessert wines, whereas it makes sense not to drink wine at all with many chocolate- and toffee-based dishes. Red dessert wines like Recioto della Valpolicella and fortified wines like the vin doux naturel Muscats are the best matches for such difficult-to-pair desserts.
Quite often, the wine itself can be a dessert, but bakery sweets can make a good match, particularly with a little bitterness like the almond biscuits that are dunked in Vin Santo. A development of this matching of contrasts is a rich savoury dish like the foie gras that is a traditional partner to Sauternes. White dessert wines are generally served somewhat chilled, but can be easily served too cold. Red dessert wines are served at room temperature or slightly chilled.