Calculate how much sugar to add to wine for a target Brix or alcohol level, convert Brix to specific gravity and g/L, or estimate potential alcohol.

Before fermentation: pure dry sucrose, using a sucrose-solution mass balance.

At least the current reading. Potential ABV is converted at Brix × 0.55.

Split the total into equal feeds
Editable two-feed illustration. Only divides the total; does not prescribe fermentation timing.

Related Calculators

Wine Sugar Formulas

The calculator models pure dry sucrose added before fermentation, converts pre-fermentation sugar-equivalent readings, or estimates a hypothetical potential-alcohol scenario. It supports 0–40°Brix and temperature-corrected readings at 20°C. Brix measures dissolved solids and is not an exact fermentable-sugar assay.

Chaptalization (sugar to add):

S = M × d / (100 - T)

Brix to Specific Gravity:

SG = 1 + B / D

Brix to sugar (g/L):

C = B × SG × 9.982

Potential ABV:

ABV = dB × 0.55
  • B is Brix, a sucrose-equivalent mass percentage. D = 258.6 – (227.1 / 258.2) * B for the empirical SG fit. The SG inverse solves this same equation; it does not switch to a separate polynomial.
  • SG — specific gravity relative to water
  • C is sucrose-equivalent concentration in g/L. M is initial must mass in grams = initial liters * SG(current) * 0.9982 * 1000. S is dry sucrose to add; T is target Brix; d is target minus current Brix.
  • Volume (L) is initial must volume. One US gallon is exactly 3.785411784 L; changing units converts the entered volume.
  • dB is starting Brix minus a corrected residual-sugar equivalent. The 0.55 factor is a rough potential-ABV yield, not a measurement of finished wine.

The retained empirical SG fit approximates sucrose solutions; it is not an exact must-density measurement. The water-density factor is 0.9982 kg/L at 20°C. Sugar addition uses mass balance, (M * current/100 + S) / (M + S) = target/100, so the added sugar increases final mass and can increase volume. It does not hold the initial volume fixed. Equal target/current readings give zero addition. Feed count only divides the total and does not set fermentation timing. Syrups, honey and concentrates require a different model.

Reference Tables

The first table uses this calculator’s approximate SG fit and 20°C water-density factor; potential ABV uses the rough 0.55 yield. The second table preserves illustrative style ranges from the original article, not recommended harvest targets or predicted finished ABV; its 42°Brix endpoint exceeds this calculator’s 40°Brix support limit.

°Brix SG Sugar (g/L) Potential ABV
181.0741939.9%
201.08321611.0%
221.09224012.1%
241.10126413.2%
261.11028814.3%
281.12031315.4%
Wine Style Target Brix at Harvest Finished ABV
Sparkling base17–199–11%
Dry white19–2311–13%
Dry red22–2512–14%
Late harvest26–3014–16%+
Ice wine / dessert32–428–13% (high RS)

Worked Example

You have 20 liters of must at 20°Brix and want to reach 23°Brix before fermentation.

  1. Initial SG ≈ 1.082992; initial mass = 20 * SG * 0.9982 * 1000 ≈ 21,620.701718 g.
  2. Current sugar equivalent ≈ 216.207017 g/L; target equivalent ≈ 251.738413 g/L. These are concentration comparisons, not the addition formula.
  3. Target minus current = 3°Brix. Mass balance includes the added dry sucrose in the final solution mass.
  4. Sugar to add = 21,620.701718 * 3 / (100 – 23) ≈ 842.365002 g (about 1.86 lb). Two equal feeds would each be about 421.182501 g; this does not prescribe timing.
  5. Expected ABV gain: (23 − 20) × 0.55 ≈ 1.65%.

Why does the ABV come up short of my Brix? The 0.55 factor is an approximate planning yield. Other dissolved solids, fermentation conditions and actual fermentable sugars affect the result. Alcohol changes refractive index and density: do not enter an untreated post-fermentation refractometer reading as residual sugar or use this model to claim measured finished-wine ABV.

Should I dissolve the sugar first? Yes. Dissolve cane sugar in a small amount of warm must before adding it back, then stir thoroughly. Adding dry sugar to a full vessel leads to uneven distribution.

What if my target is below my current Brix? A lower target is not a sugar addition and is rejected. This tool does not model dilution or blending. An equal target gives zero sugar to add.