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Brew log with attenuation and alcohol

Turn gravity readings into a brew log. The server calculates apparent attenuation and an alcohol estimate from original and final gravity in degrees Plato and states the formula used.

Input

Brewery: Mill Road Brewhouse Brew: Pale ale, batch 27 Brew day: 2 March 2026 Original gravity (°P): 12.5 Readings: id,date,stage,gravity_plato,temperature_c,note S1,2026-03-02,Pitching,12.5,12,Yeast rehydrated S2,2026-03-05,Day 3,6.2,14,…

Result

A table of readings with attenuation, original and final gravity in °P and specific gravity, attenuation, the alcohol estimate, the formula and a short log text.

A brew log keeps every reading from pitching to bottling. This tool calculates the apparent attenuation of each reading against the original gravity, takes the final gravity from the input or from the latest reading and estimates the alcohol with a stated formula. The AI words a short log text from the notes and adds no judgement on the beer.

Your texts, pages and images are processed on our own servers in the EU. Trust Center

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Who it is for

Small breweries, brewpubs, homebrew clubs and brewing courses.

Typical uses

  • Keep a clean log for each batch.
  • See how far fermentation has come.
  • Estimate the alcohol before bottling.

Example

Input

Brewery: Mill Road Brewhouse Brew: Pale ale, batch 27 Brew day: 2 March 2026 Original gravity (°P): 12.5 Readings: id,date,stage,gravity_plato,temperature_c,note S1,2026-03-02,Pitching,12.5,12,Yeast rehydrated S2,2026-03-05,Day 3,6.2,14,Krausen high S3,09.03.2026,Day 7,3.1,15,Dry hopped S4,2026-03-16,Bottling,2.8,4, Batch (l): 50 Notes: Fermenter 2. Priming sugar added at bottling.

Result

A table of readings with attenuation, original and final gravity in °P and specific gravity, attenuation, the alcohol estimate, the formula and a short log text.

A fixed example, shortened. Real results are AI-generated: please check them.

Price and limits

Price
usually 1–3 credits
Available with
Free, With package
Input limit
One page with up to 20,000 characters of HTML

Privacy

Processed on our own servers in the EU (Poland). Inputs and results are deleted after 7 days (Free) or 30 days (packages), or right after you see the result if you choose not to store them. Images are deleted right after processing.

In the API

Tool name: brew_log. Create a job with POST /api/v1/jobs and fetch the result with GET /api/v1/jobs/{id}. You find your API key in your account.

curl -X POST https://do4u.eu/api/v1/jobs \
  -H "Authorization: Bearer d4u_…" -H "Content-Type: application/json" \
  -d '{"tool": "brew_log", "url": "https://example.com/"}'

Full API documentation →

Questions and answers

Who does the calculation?

The server calculates all sums from the table. The AI only writes the text and cannot change the figures.

Which formula is used for alcohol?

Degrees Plato are converted to specific gravity, then alcohol is estimated as the difference times 131.25. The full formula is part of every result.

Can the value be used on a label?

The tool makes no statement on labelling or duty. It is an estimate from the entered readings, not a laboratory analysis.

Is my text stored?

Only as long as needed: 7 days on Free, 30 days with a package – or not at all if you choose not to store it. Processing happens on our own servers in the EU (Poland).

Can I use the result right away?

Results are AI-generated. Please read them before you publish or send them.