Measuring the Alcohol and Adjusting Sugar in Your Wine by Dan Vallish
Question:How do I figure out how much Sugar to add to and measure or adjust the amount of alcohol I will have in my wine?
Answer:At first, this hydrometer may seem daunting, but after you have used your hydrometer a few times, you will find it quite easy to figure out.
Before you begin fermenting your wine, it is important to take a hydrometer reading. This is called the "starting gravity" (SG) or the "original gravity" (OG). The hydrometer simply measures the amount of sugar in solution in your unfermented juice.
The math for the sugar to alcohol is really simple.10% sugar produces 5% alcohol. 20% sugar produces 10% alcohol. Get the idea? So looking at the hydrometer, you'll find three scales: Specific gravity, such as 1.010 1.020 and so forth. The other scale is in balling or brix. This is the % of sugar in solution. Because wine typically ferments to 1.000 or less, the math is pretty easy. The third scale is the %potential alcohol. If the beginning potential alcohol is 12%, then when your wine has finished fermenting, you should have around 12% alcohol.
To adjust your sugar level for the alcohol level of your desire, simply take a reading. If it is where you want it, add the yeast and your set.
If the sugar level in your juice is too low, add more sugar according to the chart below. Hint: Heat a little water to boiling. Add sugar to hot water to dissolve, add to juice and stir vigorously.
If the sugar level in your juice is too high, add water and stir vigorously until you get the level you want.
The chart below is a handy guide to help you figure out if you need to add sugar to your wine and if so, how much sugar to add. Add sugar before you start fermentation.