The Specific Gravity Reading (SG Reading) is taken to calculate the amount of sugar in the must by using a Hydrometer. It also helps to indicate the % of alcohol.
A 0.010 reading equals approximately 4ozs sugar ie. A 1.050 reading would indicate 20 ozs of sugar in the must.
An SG of 1.050 would indicate that if you require a wine of 12% you would need a total of 2lb sugar.
Please use the below table to help you ascertain the sugar content of your must.