Wine Must Calculator

Calculate sugar additions, juice yield, SO2 dosing, and estimated ABV for your wine must based on grape weight and gravity readings.

Results

Visualization

How It Works

Wine must preparation involves adjusting three key factors: sugar (for target alcohol), acid (for balance and flavor), and SO2 (for microbial control). Roughly 12-15 lbs of grapes yield 1 gallon of juice depending on variety and press efficiency. Sugar additions (chaptalization) raise specific gravity — each 2.25 oz of sugar per gallon increases SG by about 0.005. SO2 (metabisulfite) at 50 ppm protects against wild yeast and bacteria while allowing cultured yeast to thrive. Always measure before adjusting, and add sugar in stages rather than all at once.