To turn a Brix reading into potential alcohol, multiply it by about 0.55–0.60 — so grapes at 22 °Brix make roughly a 12–13% wine. But the more useful question is whether your fruit is ripe enough for the wine you actually want to make, and what to do if it isn’t. This calculator does both: it converts your reading across every must-weight scale, checks it against your target style, and tells you how much sugar to add if you’re short.
🍇 Brix → Potential Alcohol & Harvest Readiness
Enter your refractometer or hydrometer reading and see your potential alcohol, whether the fruit is ripe for your wine style, and how much sugar to add if it’s short.
Add acid numbers (optional — for an acid check)
How the numbers work
A grape’s ripeness for winemaking is mostly about sugar (which becomes alcohol) balanced against acid (which keeps the wine fresh). Sugar is measured as “must weight” on one of four interchangeable scales — Brix, specific gravity, Baumé or Oechsle. Potential alcohol is just that sugar read through a fermentation factor of roughly 0.55–0.60. The tool reports a likely figure (factor 0.57) plus the realistic range, because your yeast strain and how dry the wine finishes both move it.
Must-weight conversions at a glance
Every row below is the same juice expressed four ways, with the potential alcohol it carries. Handy if your hydrometer reads in specific gravity but your recipe is written in Brix.
| °Brix | Specific gravity | Baumé | Oechsle | Potential ABV |
|---|---|---|---|---|
| 16 | 1.065 | 8.9 | 65 | ~9.1% |
| 18 | 1.074 | 10.0 | 74 | ~10.3% |
| 20 | 1.083 | 11.1 | 83 | ~11.4% |
| 22 | 1.092 | 12.2 | 92 | ~12.5% |
| 24 | 1.101 | 13.3 | 101 | ~13.7% |
| 26 | 1.110 | 14.4 | 110 | ~14.8% |
| 28 | 1.120 | 15.5 | 120 | ~16.0% |
| 30 | 1.129 | 16.6 | 129 | ~17.1% |
Target Brix by wine style
Pick your style first, then ripen toward its window. These are working ranges from university viticulture and winemaking programs; cold-climate hybrids are frequently picked at the lower end because their acid stays high.
| Wine style | Harvest °Brix | Typical ABV | TA (g/L) | pH |
|---|---|---|---|---|
| Sparkling base wine | 17–20 | 9.5–11.5% | 7–11 | 2.9–3.2 |
| Dry white table wine | 19–23 | 11–13.5% | 6–9 | 3.0–3.3 |
| Off-dry / aromatic white | 20–24 | 8–11.5% | 6–9 | 3.0–3.4 |
| Rosé | 20–23 | 11–13% | 6–8.5 | 3.1–3.4 |
| Dry red table wine | 22–26 | 12–14.5% | 5.5–8 | 3.3–3.6 |
| Dessert / late-harvest | 28–42 | 12–16% | 6–11 | 3.2–3.7 |
🍇 What I measure with: for a quick field check I use a 0–32 Brix refractometer — one drop of juice, instant reading, perfect for walking the rows at harvest. For the fermenting must I switch to a triple-scale hydrometer (it reads Brix, specific gravity and potential alcohol on one stick). A refractometer reads high once alcohol is present, so the hydrometer takes over the moment fermentation starts.
A note on acid in cold climates
Northern hybrids like Frontenac, Marquette and La Crescent ripen with high titratable acidity — often 9–13 g/L when the sugar is ready. That isn’t a flaw; it’s why these grapes make such lively sparkling and aromatic whites. Enter your TA and pH in the tool for a quick verdict, and lean on cold stabilization, malolactic fermentation, or a touch of dilution rather than picking overripe and losing the freshness.
Next steps
- How to know when grapes are ready to harvest
- Will my grapes ripen? (GDD calculator)
- Wine making instructions for beginners
- How many pounds of grapes per bottle
Frequently asked questions
How do you convert Brix to potential alcohol?
Multiply your Brix reading by about 0.55 to 0.60 to estimate the finished alcohol by volume. So 22 °Brix gives roughly 12–13% ABV. The factor varies with yeast strain and how completely the sugar ferments — 0.57 is a good middle estimate for a dry wine that ferments to completion.
What Brix should grapes be at harvest?
It depends on the wine. Sparkling base is picked early at 17–20 °Brix; dry whites at 19–23; rosé around 20–23; dry reds at 22–26; and dessert or late-harvest wines at 28 °Brix and up. Cold-climate hybrids are often picked on the lower end with brighter acidity, which suits sparkling and crisp whites well.
What are Brix, specific gravity, Baumé and Oechsle?
They are four scales for the same thing — how much sugar is dissolved in the juice (the “must weight”). Brix is grams of sugar per 100 g of juice (most common in North America). Specific gravity is the density vs. water (hydrometers). Baumé is used in parts of Europe/Australia and conveniently sits close to the potential alcohol number. Oechsle is the German scale. The tool and table above convert between them.
How much sugar do I add to raise the alcohol (chaptalization)?
Roughly 17 grams of sugar per litre of must raises the finished alcohol by about 1%. The calculator works out the exact amount for your batch size and target. Add sugar before or early in fermentation, dissolved in a little juice. Note that chaptalization is regulated or banned in some wine regions — check your local rules if it matters to you.
My cold-climate grapes are high in acid. What can I do?
High titratable acidity (often 9–13 g/L in northern hybrids) is normal. Options include picking a touch riper, cold stabilization to drop tartaric acid, malolactic fermentation to soften it, gentle dilution with water (which also lowers sugar), or simply choosing a style — sparkling and off-dry whites carry bright acid beautifully. Enter your TA and pH above for a quick read on where you stand.