(Sipping wine a word at a time)
Level of sugar in the wine
If fermentation is arrested, either as a result of the yeasts failing in a gradually increasing alcohol level in the ferment, or as a result of human intervention, as a consequence there will be some remaining sugar in the wine. Even when the yeasts’ work is unhindered, most wines still have at least 1g/L of residual sugar as some sugar compounds are resistant to the action of the yeasts.
Clearly the level of sugar in the wine determines how sweet it tastes. This is quite subjective, however, and even wines that taste very dry have some degree of residual sugar.
Most DRY WINES have less than 2g/L of sugar, although levels of up to 25g/L may be present in wines which still taste dry due to the presence of acidity and tannin alongside the sugar.
The greater the amount of residual sugar, the sweeter the wine, moving through DEMI-SEC (Champagne) and OFF DRY WINES to the DESSERT WINES of the world (Passito). Some of these have incredibly high concentrations of sugar, as much as 250g/L.