Dextrose, also known as corn sugar, is a fermentable sugar that is commonly used in winemaking to increase the sugar content of wine. This can be done to increase the alcohol content of the wine, to improve its sweetness, or to adjust its balance.
 
Dextrose is a very effective fermentable sugar and is easily assimilated by yeast. It is also a relatively inexpensive sugar, making it a good choice for budget-conscious winemakers.
 
Dextrose can be added to wine at any stage of the winemaking process, from crushing to bottling. However, it is most commonly added to must (grape juice) before fermentation begins. This allows the yeast to have a consistent supply of sugar to ferment, which can help to improve the quality of the wine.