Six of the thirty calculators run right here, free — the app carries all thirty, 19 sourced recipes, and a cellar that follows a batch for years.
% here is always % OF THE WATER, by weight — that's the number that keeps a lacto-ferment safe and the one everyone argues about.
(OG − FG) × 131.25 is the bench shortcut. Log both readings every time — the app's cellar keeps the pair with the batch.
Several jars, one weighing session: the app total-up multiple projects into one shopping list the same way.
"12% by weight" names no base — Noma's garum note doesn't, and the Shockey miso table means legumes plus koji. So every reading prints side by side, exactly like the app. Ambient fish sauce wants 25–33% final salt (2–3 parts fish to 1 salt); warm-held garum at 60 °C runs ~12%.
The ceiling is chemistry, not a rule of thumb: max final acidity = starting acidity + 1.029 × target ABV (ethanol at 0.7893 g/mL converts 1:1 by moles to acetic acid). Real batches land lower — titrate to know.
g/100 mL = N × titrant × 6.005 ÷ sample — the app never estimates acidity from pH, and neither should you. Check your NaOH with KHP: 0.5000 g in 24.50 mL = 0.0999 N. Below 5.0% won't pickle safely; below 4.0% is under FDA's vinegar standard.
Salt here is % of legumes + koji — the Shockey base. 1:1 at 12% wants 240 g and lands at 10.7% final salinity; the app turns a saved miso into a batch with a tasting reminder at the aging time.