Final answer:
Sweet wines can be made by adding sugars such as sucrose and fructose during the wine-making process or using sweet-tasting additives like stevia. Late-harvest wines or stopping fermentation early can also retain natural sugars to achieve desired sweetness levels.
Step-by-step explanation:
The sweet components that can be added to make a sweet wine include various types of sugars and sweet additives.
During the fermentation process, the natural sugars in grapes, such as sucrose and fructose, are converted into alcohol by yeast. However, to increase the sweetness of the wine, additional sugar can be added either before or after fermentation. This process is known as chaptalization when sugar is added before fermentation to boost the alcohol content, or it can be dosed after fermentation, often in the form of a sweet grape juice concentrate, to add sweetness.
In some cases, other natural sweeteners such as honey or syrups might be used for flavor complexity, or sweet-tasting compounds like those found in the stevia plant might be used as a sugar substitute. Additionally, using sweet wine grapes that have higher natural sugar concentrations or harvesting grapes later in the season (late-harvest wines) can also result in a sweeter wine, as well as stopping fermentation early to retain more natural sugars.