Chaptalizing is the act of adding sugar to a grape must in order to increase the alcohol content of the finished wine. Since yeast consumes sugars to produce alcohol, if you add sugar to grape juice before or during fermentation the yeast will have more sugar to convert thus yielding higher alcohol levels.
This process is widely regulated in commercial wine making depending upon where in the world you are located. The US has federal regulations (available here) and some states enact their own regulations to go on top of the federal ones. Continue reading “How to Chaptalize Wine”