What is dead space in brewing?

Dead space is the volume of wort or beer that cannot be drained from a vessel. It includes liquid below valves, in dip tubes, under false bottoms, and trapped in hops or trub sediment.

How do I measure dead space?

Add measured amounts of water to each vessel and drain completely. The difference between what you added and what you collected is your dead space for that vessel.

How can I reduce dead space?

Use dip tubes or pickup tubes positioned near the bottom. Angle vessels slightly toward the drain. Use hop bags or baskets to contain hop material. Choose conical fermenters that drain more completely.

Does BIAB have less dead space?

Yes, brew-in-a-bag (BIAB) systems eliminate the mash tun dead space since you mash and boil in the same vessel. However, you still have kettle dead space, transfer losses and fermenter dead space.

How can I reduce dead space loss?

Use a dip tube positioned near the bottom, angle the kettle or fermenter toward the outlet, whirlpool to concentrate trub in the centre, and use a hop spider to keep hop debris contained. Cold crashing before transfer also compacts sediment, allowing more beer recovery.

BrewCalcs

Dead Space Calculator — Brewing Equipment

Calculate and account for dead space losses in your brewing system.

System Type

Kettle Dead Space

Volume below kettle valve/drain

Mash Tun Dead Space

Volume below false bottom

Fermenter Dead Space

Volume left with trub/yeast

Transfer Losses

Losses in tubing and transfers

Target Batch Size

Desired final volume

How We Calculate This

Dead Space Calculation

Total Dead Space = Kettle + Mash Tun + Fermenter + Transfer Losses. For BIAB systems, mash tun dead space is excluded since the kettle serves as the mash tun. Knowing your total dead space lets you brew the correct pre-boil volume to hit your target batch size.

Planning Around Dead Space

Your adjusted starting volume should be: Target Batch Size + Total Dead Space. This ensures you end up with the right amount of beer in the fermenter despite losses throughout the process.

Frequently Asked Questions

Related Calculators

Kettle Size Calculator

Calculate minimum kettle size for your batch with headspace allowance.

Fermenter Size Calculator

Calculate fermenter volume needed including headspace for krausen.

Mash Tun Calculator

Calculate mash tun volume needed for your grain bill and water ratio.

Boil Off Calculator

Calculate boil-off rate and total evaporation for your system.

Cooling Time Calculator

Estimate wort cooling time based on chiller type and water temperature.

Last updated: February 2026

All calculations are estimates. Always verify values and adjust based on your equipment and ingredients.