Updated: Nov 25, 2021
Where does sweetness in wine come from and how does it affect the flavour of the wine?
Sugar in wine comes from the grapes used to make said wine.
In very basic terms, the grapes are pressed to release the juice – the sugar is contained in the flesh of the grapes; yeast then munches on the sugar and creates alcohol and C02 plus a number of other things which we won’t get into now.
When there is no more sugar for the yeast to eat the wine is fully fermented or dry.
Sugar (grapes) + Yeast > Carbon Dioxide + Alcohol
The winemaker makes a decision on how they would like their wine to taste.
If they want there to be any sugar leftover from the grapes (known as residual sugar or RS), which will add body and sweetness to the wine, there are a number of ways to do this.
This is generally done based on the style of the wine they would like to make – but it can also be down to the quality of the grapes.
A lot of cheaper wines or bulk wines will leave a certain amount of RS in the wine as this will make them taster fuller-bodied and fruiter.
By increasing the level of alcohol before the fermentation has finished wine will be sweet as the yeast will be killed by the high alcohol leaving sugar unfermented.
Concentration of sugars