Specific Gravity

Specific gravity is a clever sounding word that essentially means density. Density of wine relates to the amount of sugar dissolved in the wine.

Gravity is measured in degrees. A device for measuring gravity is called a hydrometer. Water has a gravity of 1000 degrees. Obvious isn't it?

The gravity of wine increases as you add sugar. The gravity falls as the yeast eats the sugar. The alcohol produced is less dense than water. Your finished wine should have a gravity of somewhere between 1010 and 990. This means pleasently sweet and pretty dry respectivly. If your wine falls below 990 it tends to become so dry it doesn't bear thinking about.

The amount of sugar to add is a very personal thing, and is discussed elsewhere.