Lautering

What is actually happening

The husks settle into a permeable bed above the false bottom. Wort is recirculated over it — the vorlauf — until it runs clear, which both compacts the bed and returns the fine particles it will filter out.

Flow rate is the whole skill. Drawing too fast pulls the bed down onto the false bottom and compacts it into an impermeable mat, which is a stuck sparge; too slow and the brew day stretches without benefit.

Typical conditions

Ranges, not targets. These describe what is usual across the styles and breweries that use this step, and a value outside the range is a decision rather than an error.

What goes wrong here

Risks rather than certainties. This step does not cause these faults; getting it wrong can.

• Astringency — A drying, tannic harshness from over-extracted grain husk — the classic sign of sparging too hot, too long or at too high a pH.

Related steps and concepts

• Sparging — Rinsing the bed to recover the remaining sugar.
• Milling — The step that determines whether the bed will run.
• Vorlauf — Recirculating until the bed clarifies.