Recipes with calculations
Malt, hops, yeast and additions with their timing. Original gravity is estimated from the grain bill, bitterness by Tinseth and colour by Morey.
Calculators are open without signing in
A fermentation journal instead of a paper notebook
Recipes, wort batches, gravity and temperature readings, bottling and QR labelling. Gravity is stored in Brix — the scale your refractometer already uses — and instrument corrections are applied automatically. The maths is the same as in the calculators, so the journal and the calculator can never disagree.
- Calculators
- 11
- Gravity unit
- °Bx
- Works offline
- yes
- Access
- browser
Calculators — no account, no sign-in
Exactly what you need beside the fermenter: gravity and its corrections, ABV and attenuation, mash water, hop bitterness, beer colour, carbonation and yeast starters. Every tool has its own page with the formulas and reference tables.
SG ↔ Brix Specific gravity to degrees Brix and back, in gravity points. Hydrometer correction Bringing a hydrometer reading to the calibration temperature. Refractometer correction Instrument correction (WCF) and alcohol correction using the Novotný model. Alcohol and attenuation Strength and attenuation from original and final gravity. Dilution and boil-off How much water to add or boil off to reach the target gravity. Pressure carbonation Pressure for target CO₂ saturation at a given temperature. Priming sugar How much sugar to add when bottling. IBU How many IBUs the hops give during the boil. Mash How much water to add and to what temperature to heat it. Colour EBC, SRM and Lovibond with a preview of the colour itself. Yeast starter Whether you have enough yeast and what starter to make.
What the journal can do
Everything you used to scribble in a notebook in the brewhouse — with calculations and a history you cannot lose.
Wort batches
Codes like B-2026-001, a snapshot of the recipe as it was brewed, and a lifecycle from planned to bottled with validated transitions.
Measurement log
Refractometer and hydrometer, gravity in Brix, temperature, pH and pressure. Instrument and alcohol corrections are applied automatically.
Fermentation chart
Three gravity curves — the raw refractometer reading, true gravity and the hydrometer — together with temperature and the rate at which gravity falls.
Bottling and priming
Carbonation method, target CO₂ volumes and the sugar for a batch, taking residual gas into account.
QR labelling
Batches of unique codes, a ready A4 label sheet, camera scanning and a history of what happened to every bottle.
How it works
- 1
Create a recipe
Describe the ingredients and volumes — gravity, bitterness and colour are estimated right away.
- 2
Brew it and start a batch
The batch gets a code and the recipe is saved as a snapshot, so later edits cannot rewrite history.
- 3
Record your readings
Gravity, temperature, pH, pressure. ABV, attenuation and the chart update themselves.
- 4
Bottling and labels
Calculate the primer, issue the codes and print a sheet of labels with QR codes.
Calculations, not guesswork
Gravity is calculated by the same formulas in the journal and in the calculators. SG ↔ Brix uses the cubic approximation from the Brewer’s Friend tables; hydrometer correction uses the ratio of water densities from Tanaka et al. (Metrologia, 2001); refractometer alcohol correction uses the Novotný model (Ascher, 2021), which holds throughout fermentation. Raw instrument readings are kept exactly as entered, so changing an instrument coefficient recalculates the whole history without losing anything.
The results are estimates from standard formulas. They are meant for keeping a log and checking against targets, and are no substitute for laboratory analysis.
Start your journal on the next brew day
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