Beer Fermentation Timeline
Use next-day gravity stability, recipe target, yeast temperature and batch condition before scheduling packaging. Inputs stay in your browser.
American Homebrewers Association guidance uses matching hydrometer readings on consecutive days—not airlock activity or a fixed fermentation day—to judge whether fermentation appears complete.
Context matters.
- Airlock bubbling can stop before fermentation is complete and can continue after fermentation from temperature or pressure changes.
- For bottles, use a recipe-specific priming calculation and sound pressure-rated bottles; excess fermentable sugar or incomplete fermentation can create dangerous pressure.
- Suspected contamination, abnormal film, rope, mold, vessel overpressure or package swelling needs experienced brewing-safety evaluation rather than tasting or waiting.
Sources & scope
The calculation guide and this source trail show what the result means, where the rule came from and when it was last reviewed. This is source-and-calculation QA, not a claim of medical, legal, tax or other professional review; time-sensitive decisions still belong with the linked authority.
A visible path from input to answer.
Use next-day gravity stability, recipe target, yeast temperature and batch condition before scheduling packaging. The page keeps the calculation scope and its limits beside the result so the output can be checked, copied or revisited.
- Read the record. The calculator uses Fermentation started, Gravity checked on, Original gravity, Previous specific gravity and Current specific gravity and 6 additional fields supplied in the form.
- Apply the scope. It applies the Homebrew process planning — user hydrometer, yeast-temperature and batch-condition inputs reference and the explicit date, unit and counting conventions shown in the result.
- Expose the checkpoints. Intermediate rows, warnings and timeline events stay visible; the emphasized row identifies the primary checkpoint when one exists.
American Homebrewers Association guidance uses matching hydrometer readings on consecutive days—not airlock activity or a fixed fermentation day—to judge whether fermentation appears complete.
- Packaging checkpointAug 30, 2026
Calculation purpose: Use next-day gravity stability, recipe target, yeast temperature and batch condition before scheduling packaging. This is a conditional reference output; the linked source and the situation-specific facts control the decision.
Calendar inputs use plain year-month-day semantics. Leap days, month ends, date-pair order and unsupported dates are checked before the result is shown.
Rule set 2.0.0 · Last reviewed 2026-08-20 · Next review due 2027-02-20. The source panel below contains the linked evidence.
What to know before using the result.
How does CalcSpan decide fermentation appears complete?
It follows AHA hydrometer guidance: matching specific-gravity readings taken on consecutive days, plus the entered recipe target and yeast-temperature history.
Why is airlock activity not an input?
Bubbles can stop while fermentation continues or appear from temperature and pressure changes after fermentation. Gravity readings are the useful decision signal.
Does the packaging checkpoint calculate priming sugar?
No. Bottlers must use the recipe's priming guidance and sound pressure-rated bottles; incomplete fermentation or excess sugar can create dangerous pressure.