Wine lovers must be familiar with words such as "dry red", "sweet white" and "residual sugar". So what exactly is "residual sugar"? Where does the sugar of wine come from? What does "dry red" mean? What is the relationship between high and low sugar content and wine quality?
what is "residual sugar
When making wine, winemakers use yeast to convert sugar from grape fruits into alcohol for delicious wine. But in most cases, the sugar in the grape fruit is not completely converted into alcohol, so some sugar remains in the wine, which is called residual sugar. People usually refer to "dry red" "sweet white" in the "dry" and "sweet" is used to express the concept of residual sugar content.
Where does the sugar come from
Yeast naturally stops fermentation In the process of alcohol fermentation, when the sugar content is too high or the alcohol content reaches a certain degree, yeast will be difficult to survive, fermentation activity slows down until it stops, the liquor is likely to leave unfermented sugar. For example, the famous Su Yu expensive sweet white, its wine grapes in the role of expensive rot bacteria, sugar and flavor substances are highly concentrated, after the completion of alcohol fermentation, wine also left a large amount of sugar, expensive wine sweet glycol taste will come from this. At the same time, residual sugar in wine may also come from a very small amount of sugar that cannot be converted by yeast, such as carboy sugar, which is why some dry wines contain very little residual sugar.
artificial interruption of the fermentation process In order to produce a particular style of wine, some winemakers will also choose to artificially interrupt the fermentation process of alcohol, so that the wine retains a certain amount of residual sugar. There are two main ways to artificially interrupt fermentation: one is to strengthen the fermented liquor with spirits such as brandy, killing yeast, thus producing a higher alcohol content of the enhanced wine, such as Porter and Shirley, and the other is to ferment The liquor is cooled or injected with carbon dioxide to inhibit yeast activity, and then the yeast is filtered out of the liquor for the purpose of interrupting fermentation, and wines produced using this method are generally less alcoholic, such as as asti sparkling wine in Italy.
addition to the above two ways, the sugar in wine may also be derived from artificial addition. In the case of champagne, after the steps of fermentation of the base wine, secondary fermentation in the bottle, and spitting mud, the winemaker adds a mixture of wine and sugar to the liquor, which is then sealed with cork and barbed wire. The amount of sugar in the mixture determines the final sugar content of the champagne, which in turn determines the type of champagne, and naturally very dry champagne does not add sugar at this stage.
Fact, added sugar is a very old winemaking technique, and in some cooler regions or vintages, winemakers add sugar before the alcohol ferments to increase the alcohol content of the wine. But many countries now do not allow the technology, such as Argentina, Australia, Portugal and Italy, while countries and regions such as France, Germany, Canada and the United States, which allow it, also have very strict dosage controls on added sugar.