Mutage

Mutage /ˈmjuːtᵻdʒ/ MEW-tij is a wine making technique for making sweet wines.

The typical process involves the addition of alcohol to the must so that the fermentation process is prematurely stopped. Most yeast dies when the alcohol content in their environment is raised to approximately 13-15%. By stopping the fermentation of sugars, a sweet taste of the wine is achieved. This technique is used to make port wine and other sweet wines with high alcohol content.