♨️ Pre-boil Volume Calculator for Brewing
Plan kettle volume from target batch size, boil time, evaporation and losses.
This free tool helps you turn project measurements into a practical planning estimate. Enter values in Vaelden’s interactive calculator, review the result, and confirm important assumptions against supplier data, measurements, codes or qualified advice before committing materials or money.
Open the Pre-boil Volume calculator →
How to calculate pre-boil volume
Method: Pre-boil volume = target fermenter volume + boil-off per hour × boil time + system losses
- Set the required fermenter volume.
- Measure the kettle’s real hourly boil-off rate.
- Add transfer, trub and equipment losses.
Worked example
Using these planning inputs:
- Target fermenter volume: 23
- Boil duration: 1 h
- Boil-off rate: 3
- Kettle and transfer losses: 2
Required pre-boil volume: 28.00 L
Reality check: Boil vigour, kettle geometry and weather change evaporation; measure the actual system over repeated batches.
Before you calculate
Use consistent units and the best measured inputs available. Real materials, equipment, site conditions and tolerances can change the result. Vaelden shows planning estimates; regulated, structural, electrical, plumbing, pressure and other safety-critical work still requires appropriate local compliance and professional advice.