Free tools for winemakers
Chaptalization calculator
Sugar to reach a higher sugar or alcohol
Sugar to add
Type the volume, the current reading and the target.
Before fermentation only. Once fermentation starts, alcohol throws the reading off: a hydrometer shows less sugar than is really there, a refractometer more.
Check your local rules. Adding sugar is restricted or banned in many wine regions.
How do we calculate this?
The exact formulas used in this tab:
What this calculator does
Works out how much table sugar to dissolve into must to raise it to a higher sugar reading or to a target potential alcohol, and how much the volume grows as the sugar dissolves.
- Type the reading in Brix, SG, Baumé, Oechsle or KMW.
- It is for must before fermentation, including fruit wines such as pomegranate or date wine.
- It doesn’t tell you whether adding sugar is allowed where you make wine.
The formula
S1, S2 = sugar (g/L) now and at the target = Brix × 10 × SGTarget alcohol → target Brix = alcohol % ÷ 0.59Sugar (g) = V × (S2 − S1) ÷ (1 − 0.00063 × S2)0.00063 = 0.63 L of volume per kg of dissolved sugarNew volume = V + 0.00063 × sugar (g)Potential alcohol (%) ≈ Brix × 0.59
Worked example
- 1,000 L of must
- Now: 20 °Bx
- Target: 22 °Bx
- How much the sugar must rise 240.27 g/L − 216.63 g/L = 23.64 g/L
- Allow for the volume the sugar adds 1 − 0.00063 × 240.27 = 0.8486
- Sugar for the whole tank 23.64 × 1,000 ÷ 0.8486 ≈ 27,857 g = 27.857 kg
- New volume 1,000 + 27.857 × 0.63 = 1,017.6 L
- Potential alcohol, up from 11.8 % vol 22 × 0.59 = 13 % vol
Add 27.857 kg of table sugar
Questions
Why does the volume grow?
Dissolved sugar takes up room: about 0.63 L for every kilogram. The calculator allows for it twice: in the amount, by dividing by 1 − 0.00063 × S2, and in the new volume it shows. Without that correction the amount would come out too low.
Can I aim for an alcohol level instead?
Yes. Choose “Target alcohol” and type it, for example 13.5 % vol. The calculator turns it into a sugar target, here 22.88 °Bx. For the same 1,000 L at 20 °Bx that is 40.598 kg of sugar. The 0.59 factor is an estimate: the alcohol you actually get depends on the yeast and the fermentation.
Can I use it once fermentation has started?
No. Alcohol throws the reading off: a hydrometer shows less sugar than is really there and a refractometer shows more, so the answer would be wrong either way. Use a reading taken before fermentation.
What if the must has too much sugar?
Then the sugar comes down with water, not up with sugar. The water addback calculator works out how much water brings the must to a lower target, and the acidity after. Check first whether adding water is allowed where you make wine: the EU allows it only for a specific technical need, and the US and Australia limit it.
Am I allowed to add sugar?
It depends on where you make wine. Many regions restrict or ban adding sugar, or allow it only in some years or up to a limit. For example, the EU sets enrichment limits by wine-growing zone, and the US has its own rules. Check your local rules first; the calculator only does the arithmetic.
EU: Regulation (EU) No 1308/2013, Annex VIII, Part I. US: 27 CFR 24.177.
Does it work for fruit wine?
Yes. Measure the fruit juice with a refractometer or hydrometer the same way, before fermentation, and type the reading. Many fruit juices hold less sugar than grape must, so a fruit wine often needs more sugar to reach the alcohol you want.