Chemex 800 g

Name: Chemex 800 g
Yield: 800 g
Ingredients: 55 g coffee; 800 g water at 205F

by Matt KennardUpdated October 1, 2026

1:14.5.

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1:14.5. The house ratio everything else is matched to.

Brew process

Rinse

Rinse the paper with hot water and let it run through into the carafe, then pour that water away. It washes the paper taste out and warms the glass; a cold Chemex takes heat out of the brew before the coffee ever sees it.
Bloom 0:00 · 110

Start the timer and pour 110 g — twice the dose — over the whole bed, wetting every grain. Then leave it. The grounds swell and push out carbon dioxide, and water cannot extract evenly through gas.
Pour 0:45 · 450

Add 340 g in slow circles, keeping the water off the paper and on the coffee. Pouring down the side sends water past the bed rather than through it.
Pour 1:40 · 800

Add the last 350 g the same way, finishing with the bed level rather than heaped up one side.
Drawdown 5:00

Target: the water should be through by 5:00. Much faster and the grind is too coarse — go one step finer. Much slower and it is too fine, or the bed was stirred; go coarser.

These numbers were written for a Medium-dark roast. That is what the temperature and the time below assume — it is a setting, not a fact.

Dogspeed Flat Track Coffee Medium-dark · Latin America, varied seasonally — typically Colombia Supremo, Guatemala (Huehuetenango or Marilandia) and Brazil (Vila Boa natural) The one I use
Lucem Merit Coffee Medium · Blend, Honduras and Brazil; components shift, and it has also been listed as Peru and Colombia
Power Button Superthing Coffee Medium-dark · Blend, 50% washed Guatemala and 50% washed Ethiopia
Andino Leal Merit Coffee Medium · Huila, Colombia, from a committed group of small-scale producers
La Sagrada Praxis Coffee Roasters Medium-dark · Latin America, rotating seasonally through direct-trade lots (Mexico, Costa Rica and Guatemala among them)
Roaster's Blend Merit Coffee Medium-dark · Blend, Honduras and Colombia

If your bag is lighter or darker than that

55 g to 800 g is about 1:15. Everything below is relative to this recipe's own numbers.

Temperature: Go hotter. A lighter roast is denser and gives up less at the same temperature — take it to the top of the range, or just off the boil.
Time: Give it longer. Another fifteen to thirty seconds of contact, whether that is a slower pour or a longer steep.
Grind: Grind finer, one step. Light roasts under-extract before they over-extract, and sour is the failure you will meet first.
Dose: Leave the dose alone at first. If it is still thin after the other three, add a gram or two.

Temperature: Go cooler. A dark roast is brittle and gives up everything it has immediately — back off five degrees or let the kettle stand a minute.
Time: Cut it short. Stop the brew at the first sign of it slowing down; the last of the drawdown is where the ash comes from.
Grind: Grind coarser, one step. Bitter and hollow is the failure you will meet first, and coarser is the fix.
Dose: You can use slightly less and lose nothing. A dark roast tastes stronger than it is.

Temperature: The temperature on this recipe is written for exactly this roast. Start there.
Time: The time is the time. Change it only after you have tasted it once as written.
Grind: Grind is still the one thing worth moving. Everything else in the recipe is fixed so that it can be.
Dose: The dose below is what these numbers were dialed at.