Wine (or cider) plus water plus mother, mixed to a chosen starting ABV. The planner's rule: total volume = wine volume × wine ABV ÷ target ABV; water fills the rest. Worked (the calculator's default): 750 mL wine at 12% to a target of 6% = 1,500 mL total — add 750 mL water. Add 300 mL of 6%-acidity mother at the same target: the mother carries no meaningful ethanol, so water drops to 450 mL and the plan's starting acidity rises to 1.20%.
The ceiling is chemistry: max final acidity = starting acidity + 1.029 × target ABV (ethanol at 0.7893 g/mL converted 1:1 by moles to acetic acid, g per 100 mL). It's a ceiling — real batches land lower; titrate to know.
Keep the target inside NC State's 5.5–7% window for a vinegar that ferments well and pickles safely (the calculator notes it informationally when you step outside).
Never estimate acidity from pH; measure it. A measured sample + standardized NaOH + the titrant used: g/100 mL = N × titrant × 6.005 ÷ sample. Worked: 5.0 mL, 0.100 N, 40.0 mL used = 4.80 g/100 mL. Diluted 10 mL to 100 and titrated a 10 mL aliquot: multiply the sample by aliquot ÷ dilution (1.0 mL effective) — 8.0 mL gives the same 4.80.
Wine-kit readings are g/L as tartaric: multiply by 0.8002 for acetic (62.5 g/L = 50.0 g/L = 5.00 g/100 mL).
NaOH solutions age; every honest titration starts from a fresh normality. KHP's factor is 204.22 g/mol: N = KHP grams × 1000 ÷ (204.22 × NaOH mL) — 0.5000 g in 24.50 mL = 0.0999 N. Log the date with it; the app re-reminds when your stored solution ages past your own limit.
Dilute to the finishing acidity with C₁V₁ = C₂V₂: 1,000 mL at 7.4% to 5.0% wants 1,400 mL total — add 480 mL water (the calculator's own answer).
| Reading | Says |
|---|---|
| Below 5.0% acidity | Below the 5% NC State lists for preserving and pickling |
| Below 4.0% | Under FDA's 4 g/100 mL vinegar standard |
The batch template: ferment at 80–85 °F (NC State's ideal home range), then the optional pasteurize step at 140–160 °F held 30+ minutes.