Hydrometer

Here's a more scientific way to determine how the fermentation is coming along: use a hydrometer. Basically speaking, the hydrometer is a floating scale to determine the amount of sugar left in the wine. As the fermentation progresses, there'll be less sugar. In this video, the sugars are at 10% (or 10-degrees Brix...named after some German dude who invented this scale). To learn more about Brix, go to: http://www.kenswineguide.com/wine.php?word=18