Agitation

Any disturbance of the coffee bed during brewing — pouring, stirring, swirling, plunging. Increases extraction by exposing more of the grounds to fresh water.

Why it matters — Agitation is one of the most useful variables in filter brewing. Adding agitation increases extraction; removing it dampens extraction. Used carefully, agitation lets you fine-tune cups without changing grind.

Good to know

• Aggressive pour patterns, a spoon stir during bloom, or a swirl of the dripper at the end of the brew all increase agitation.
• Light, even pours decrease agitation. If your filter coffee is over-extracting, try gentler pour technique before grinding coarser.