


What makes some wines dry and others sweet, and how can I tell which is which?


The relative dryness of a wine is measured in terms of residual sugar, or RS in the wine geek’s argot. This is the level of natural grape sugar left after fermentation. Once grapes are crushed, yeast feeds off grape sugar to produce alcohol and carbon dioxide. It’s hard to predict exactly how yeast will behave, and they rarely finish the job completely, mainly because some sugars are not easily fermented. There’s always a little sugar left, even in the case of “dry” wines, though the level is pretty trivial. Technically, a wine is considered dry if it contains less than two grams of sugar per litre of fluid. But even here the perceived dryness of the wine depends on a host of other components, most notably acidity. If there’s a lot of acidity in the wine (as in the case of, say, riesling), it can still taste pretty dry even if it contains much more than two grams per litre.


Still curious? read Kevin Zraly’s Complete Wine Course.


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