Boil-Off Rate Calculator
Calculate your system's boil-off rate from pre and post boil volumes.
Volume at the start of the boil
Volume at the end of the boil
Total boil time (usually 60 or 90 min)
Internal diameter of your brew kettle
How We Calculate This
The calculator determines your system-specific boil-off rate from measured pre-boil and post-boil volumes.
Formulas
- Total boil-off = Pre-boil volume - Post-boil volume
- Boil-off rate = Total boil-off / Boil duration (hours)
- Boil-off % = (Total boil-off / Pre-boil volume) x 100
Typical ranges: 10-15% for electric systems, 12-18% for gas. Record over several brews for a reliable system profile.
Frequently Asked Questions
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Last updated: March 2026
All calculations are estimates. Always verify values and adjust based on your equipment and ingredients.