Convert between Brix (°Bx) and specific gravity measurements for winemaking.
This calculator uses a high-precision polynomial model for accurate conversion between Brix (sugar content) and specific gravity measurements commonly used in winemaking.
Brix (°Bx) is a unit of measurement used to estimate the sugar concentration in grape must or juice. One degree Brix corresponds to 1 gram of sucrose in 100 grams of solution. In winemaking, Brix is measured using a refractometer or hydrometer and provides a quick indication of the potential alcohol content that can result from fermentation. Brix values at harvest typically range from 20–26 °Bx, depending on varietal, region, and stylistic intent.
Specific gravity (SG) is a dimensionless number that compares the density of a liquid to the density of water. In winemaking, SG is commonly used during fermentation monitoring and is measured using a hydrometer. Pure water has an SG of 1.000, and musts with dissolved sugars typically measure between 1.070 and 1.110 before fermentation. As fermentation progresses and sugar is converted to ethanol, SG decreases—often approaching 0.990 to 0.998 when fermentation is complete.
Brix and specific gravity are directly related through known conversion formulas, though their relationship is nonlinear. Because ethanol and sugar affect density differently, adjustments for alcohol content must be considered when converting mid- or post-fermentation readings. Tools and tables exist to accurately convert between Brix and SG at various stages of fermentation, including corrections for temperature and alcohol interference.
The potential alcohol in wine is estimated by measuring the initial sugar content (Brix or SG) before fermentation and applying a conversion factor. A common estimate is that each 1 °Bx will yield approximately 0.55–0.60% alcohol by volume (ABV). For example, must at 24 °Bx may result in 13.2–14.4% ABV depending on yeast efficiency and fermentation completion. For more precise estimations, winemakers often use the formula:ABV = (Initial Brix × 0.59), or refer to empirically derived Brix-to-alcohol charts.
Accurate measurement and conversion of Brix and specific gravity are essential for controlling fermentation, achieving stylistic targets, and ensuring regulatory compliance. Monitoring these parameters allows winemakers to adjust techniques in real time, such as chaptalization, dilution, or nutrient addition, to support a clean and complete fermentation.