Percolation

Chemex brewing guide

The thickest filter in coffee — clarity in glass.

Difficulty
Brew time
4–6 min

The science

The Chemex is a percolation brewer defined by its filter: bonded paper 20–30% heavier than a standard cone filter. That thickness slows the flow and traps oils and nearly all fines, producing the clearest, most tea-like cup in coffee — at the cost of body. Everything about brewing a Chemex flows from compensating for that filter.

Because the paper restricts flow so aggressively, grind coarser than you would for a V60 — medium-coarse — or the bed will stall and over-extract. The deep cone also builds a tall bed at larger batch sizes, so keep pours slow and staged to avoid compacting it. Set the folded, multi-layer side of the filter against the pouring spout so the air channel stays open and the brew can breathe.

Temperature and ratio behave like any percolation brew: 92–96 °C, around 1:16. Expect a longer total time than a V60 — four to five minutes for a standard batch is normal, and chasing a faster drawdown by grinding fine is the classic way to ruin one. The Chemex rewards patience and punishes force.

The essentials

Grind
medium-coarse · 52–66/100
Ratio
1:15–1:17
Brew time
4:00–6:00
Water temp
92–96 °C
Agitation
Slow, staged pours; avoid stirring the deep bed

Brew Chemex with a guided timer.

Blend paces every pour, holds the Chemex to its numbers, and saves what you change for next time. Launching soon on iOS and Android.

Common questions

What grind size should I use for Chemex?

Aim for a medium-coarse grind, around 52–66/100 on Blend’s 0–100 scale. If the brew runs fast and tastes thin, go finer; if it stalls or turns bitter, go coarser.

What coffee-to-water ratio works best for Chemex?

Between 1:15 and 1:17 coffee to water. Start near 1:16 and add water for a lighter cup or hold back for more strength.

How hot should the water be for Chemex?

92–96 °C suits Chemex. Within that window hotter water extracts faster. Ease it down if the cup turns harsh, up if it tastes flat.