Kitchen calculators

Every sourdough ingredient is a percent of total flour. Total flour includes the flour inside the starter, so a 20% starter on 500 grams of flour is 100 grams of starter, and a 100% hydration starter is 50 grams of that flour. The water you pour is what’s left after the starter’s water is counted. A country loaf at 75% hydration, 20% starter, and 2% salt is the default.

ABV from a hydrometer is (OG − FG) × 131.25. The alternate formula, (76.08 × (OG − FG) / (1.775 − OG)) × (FG / 0.794), sits beside it because the two diverge as the beer gets stronger. A refractometer reading of finished beer needs a correction: this page uses Sean Terrill’s 2011 cubic, with a wort correction factor that defaults to 1.04. Specific gravity has no imperial or metric form.