Specific Gravity to Brix

How it is calculated

The tool evaluates a cubic polynomial fitted to sucrose-solution tables: °Bx = 182.4601·SG³ − 775.6821·SG² + 1262.7794·SG − 669.5622. SG is specific gravity, a plain number close to 1 (water is 1.000), and the answer is degrees Brix, roughly grams of sucrose per 100 g of solution, shown to two decimals. An SG of 1.000 gives 0.00. The accepted range is 0.980 to 1.200; anything outside it, such as 1050 or 0.97, shows no result. Values below 1.000 return a negative Brix (0.990 gives −2.62), which is normal for a fermented, alcoholic liquid but is not a true sugar reading. The polynomial is only meaningful for the gravities seen in brewing and winemaking.

Common mistakes

• Typing the gravity as points (50) or with the decimal removed (1050). The field takes the decimal SG, such as 1.050, and values like 1050 or 50 show no result.
• Entering a post-fermentation gravity and expecting a true Brix. Alcohol lowers density, so the converted figure no longer represents sugar, and below 1.000 it turns negative.
• Entering a reading that is not corrected to the hydrometer's calibration temperature, which shifts SG and therefore Brix.
• Comparing with a refractometer reading taken during fermentation, which also needs its own alcohol correction.
• Dropping the third decimal. Near 1.050, each 0.001 of SG is worth about 0.23 °Brix (1.051 gives 12.62), so rounding 1.0505 to 1.05 moves the answer from 12.51 to 12.39.