How does Brix relate to potential alcohol?

Each degree of Brix contributes roughly 0.55 to 0.59 percent alcohol by volume when fermented to dryness. This calculator uses a factor of about 0.57, so a 22 Brix must yields close to 12.5 percent ABV. The exact figure varies slightly with yeast and temperature.

What is the difference between cane sugar and dextrose?

Cane sugar (sucrose) is fully fermentable and the standard for chaptalization. Dextrose (corn sugar) is sold as a monohydrate that is about 9 percent water, so you need slightly more of it by weight to add the same fermentable sugar. The tool corrects for this automatically.

How much does adding sugar dilute or raise the volume?

Dissolving sugar raises the volume slightly, but the effect is small for typical additions and this calculator works on the must volume you enter. For very large additions, re-measure Brix after dissolving and stirring to confirm you hit the target.

Is chaptalization legal where I live?

Adding sugar to must is permitted for home winemaking in most countries but is regulated or restricted for commercial wine in some regions, such as parts of the EU. This tool is intended for home winemakers; check local rules before commercial use.

Can I add too much sugar?

Yes. Pushing potential alcohol much above 14 to 15 percent can stress or stall the yeast, leaving residual sugar and an unbalanced wine. If you need a high-alcohol result, choose an alcohol-tolerant yeast strain and add sugar in stages.

Wine Chaptalization (Sugar Addition) Calculator

When your grapes or fruit do not have enough natural sugar to reach the alcohol level you want, chaptalization — adding sugar to the must before fermentation — makes up the difference. This calculator tells you exactly how much sugar to add to hit your target ABV.

How it works

The calculator works in three steps.

Step 1 — target Brix. Potential alcohol relates to sugar concentration. Each degree Brix yields roughly 0.57 % ABV when fermented dry, so:

target Brix = target ABV / 0.57

Step 2 — Brix gap. Subtract your current Brix from the target. If the gap is negative your must is already sweet enough and no sugar is needed.

Step 3 — sugar mass. Brix is grams of sugar per 100 g of solution. The tool converts the Brix gap into grams of pure fermentable sugar needed for your batch volume, accounting for the density of the must, then adjusts for the sugar type:

Cane sugar (sucrose) — fully fermentable, used as-is.
Dextrose monohydrate — about 9 % water, so you need roughly 1.1× the mass.
Grape concentrate — partly water and acid; the tool scales for its fermentable-sugar fraction.

Example

A 19 °Brix must, 20 litres, targeting 13 % ABV needs a target Brix of about 13 / 0.57 ≈ 22.8. The roughly 3.8 °Brix gap works out to a sizeable cane-sugar addition; the tool shows the exact grams per litre and total.

Tips

Dissolve fully before re-measuring. Undissolved sugar gives a falsely low reading.
Stay below about 14–15 % potential alcohol unless you use an alcohol-tolerant yeast — high sugar can stall fermentation.
Re-check Brix after stirring to confirm you hit the target.

All calculations run locally in your browser.