How it works
How it is calculated
A hectolitre is 100 L, so a dose in g/hL times the volume in hL gives grams. Doses per litre are multiplied by the volume in litres.
Useful conversions: 1 g/hL = 10 mg/L (10 ppm), 1 g/L = 100 g/hL, and 1 lb per 1,000 US gal ≈ 12 g/hL.
Where the dose comes from
Start from the supplier’s technical sheet. For fining agents such as bentonite, the right dose comes from a bench trial: prepare samples with increasing rates (steps of 10 g/hL, or 100 mg/L, are common), let them settle, heat-test them against an untreated control and pick the lowest rate that stays clear.
Worked example (US units)
Bentonite at 60 g/hL in 1,200 gal (45.4 hL): 60 × 45.4 = 2.7 kg, about 6.0 lb.
Questions winemakers ask
How do I convert lb/1,000 gal to g/hL?
Multiply by about 12. One pound in 1,000 US gallons is 453.6 g in 37.85 hL, or 11.98 g/hL.
How do I convert g/hL to ppm?
Multiply by 10: 25 g/hL = 250 mg/L = 250 ppm.
Does this work for liquids?
Yes. Pick mL/hL or mL/L and the result comes out in mL.