Sugar in wine – a topic that has claimed a lot of interest in the past ten years. For many, the topic has spawned from more focus on health and weight. For a smaller majority, sugar, or rather lack of sugar is a sign of quality of wine. I must admit that for me it was initially the first, and during recent years, as I have learned more, the latter. As I have started understanding different methods of wine making, I have also understood the role of sugar and the importance of where it comes from. Here is a quick summary and my attempt to demystify the topic of sugar in wine.
With a very black and white approach, there are two sources for sugar in wine: the fruit sugars in grapes themselves, and in some instances cheap wine producers will add sugar concentrate to sweeten a wine. Let me address the latter first. Why is it the cheap wine producers that add sugar? It may be because they use second presses of wine must (the sweetest juices flow out in the first press) or they use poor quality grapes, and sugar is used to hide unwanted tastes. Small amounts of sugar are also added to provide some consistency in taste, as yearly harvests are always a bit different. In conclusion, high quality wines usually have little or no added sugar.
Before we continue, I would like to distinguish between added sugar and residual sugar. Residual sugar (RS) can be either sugars that the yeast did not ferment or sugar that the winemaker added after the wine fermented, or both. The latter is called “added sugar”, and it is mixed to the wine before bottling or corking. RS is usually measured in grams of sugar per liter of wine, often abbreviated to g/l or g/L. Unfortunately you seldom see how much of this is added sugar. But you can make some conclusions of course. (a champagne usually has some added sugar when RS is more than 4 or 5g per liter). Added sugar is usually table sugar or grape concentrate in the form of a liquor. Wine producers usually claim that the recipe of the liquor is a family secret, but I suspect they just don’t want to reveal the gross content.
To move on to sugar content as implication of quality, the amount of the natural residual sugar is controlled by the length of the fermentation process. If a wine is sweet, it doesn’t mean that sugar concentrate has been added, it means that the fermentation process has been stopped (naturally or for example by cooling) to leave in a certain sweetness to the wine intentionally. This is how many semi-sweet wines are made, for example Rieslings. A shortened fermentation also leads to a lower alcohol percentage. Why? Because alcohol is created as a side product in the fermentation process with the yeast eating the sugar from the fruit must. If the fermentation process is stopped early, the generation of alcohol is left short.
Sugar is of course not always a bad thing. Acidity and sugar content are balancing factors in wine. Sugar also helps wine age more gracefully. If you have patience, say for a decade or two (or three), then RS can bring deep complexity and richness.
How much sugar is there in wine? The infograph below created by WineFolly gives a pretty good overview. These days, sugar content is often marked on the labeling of the bottle. If not, tech-sheets are available on the producers or distributors website. In Sweden, it is mandatory to inform consumers of the sugar content of each wine. So, it is marked clearly on the price-tags in the state monopoly store (as well as on their website).
In conclusion: Here is yet another reason to avoid cheap, mass produce wines. If you check the sugar content in wine before you make a purchase, you can make quite good conclusions about the wines quality.