Potential alcohol
12.47%
Starting gravity: 1.090 SG
Homemade Wine ABV and Potential Alcohol Calculator
Enter the starting gravity of your must from a hydrometer (SG) or refractometer (Brix) to see its potential alcohol. Add a current hydrometer reading to see how much alcohol has formed so far, and plan a sugar addition if the must is too weak for the wine you want.
ABV so far
10.50%
1.97% still to ferment
Sugar to reach target ABV
0.44 lb (200 g)
How the wine formulas work
Potential alcohol:(starting gravity − expected finishing gravity) × 131.25. Dry wines usually finish between 0.990 and 0.998, so the default is 0.995.
ABV so far: the same equation with your current hydrometer reading. Once the gravity stops dropping for several days, that number is the finished ABV.
Advanced formula:(76.08 × (OG − FG) ÷ (1.775 − OG)) × (FG ÷ 0.794) gives a higher figure for strong musts. Use it for high-gravity wines; the standard formula matches most hydrometer potential-alcohol scales.
Brix to SG: Brix is converted withSG = 1 + °Bx ÷ (258.6 − (°Bx ÷ 258.2) × 227.1).
Sugar addition (chaptalization):pounds = (target OG − current OG) × 1000 × gallons ÷ PPG, using 46 PPG for table sugar. Chaptalization rules vary by country for commercial wine; for home winemaking it is a common way to correct a thin fruit must.
Brix, SG, and potential alcohol
| °Brix | Specific gravity | Potential ABV (dry to 0.995) |
|---|---|---|
| 16 | 1.065 | 9.2% |
| 18 | 1.074 | 10.4% |
| 20 | 1.083 | 11.5% |
| 22 | 1.092 | 12.7% |
| 24 | 1.101 | 13.9% |
| 26 | 1.110 | 15.1% |
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FAQ
What is potential alcohol in winemaking?
Potential alcohol is the ABV a must would reach if all of its sugar fermented. This calculator estimates it as (starting gravity − expected dry gravity) × 131.25, with dry wine finishing around 0.995.
What starting gravity do I need for 12% wine?
About 1.086 if the wine ferments dry to 0.995 (0.995 + 12 ÷ 131.25). That is roughly 20.6 °Brix. Ripe wine grapes are commonly harvested between 20 and 26 °Brix.
How much sugar raises the potential alcohol by 1%?
1% ABV needs about 7.6 gravity points. At 46 points per pound per gallon, that is about 0.17 lb (75 g) of table sugar per US gallon of must.
Can I use a refractometer reading for the current gravity?
Only before fermentation starts. Alcohol distorts refractometer readings, so use a hydrometer for the current gravity, or correct the reading with the refractometer calculator.