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The exact coffee-to-water ratio for every Chemex size, with bloom amounts, pour timing, and grind guidance.
Quick answer
The standard Chemex ratio is 1:16 — that is 1 gram of coffee to 16 grams (ml) of water. For a 6-cup Chemex, use 56 grams of medium-coarse ground coffee with 888ml of water. Bloom with twice the coffee weight in water (112ml) for 30 seconds before the main pour.
Coffee
56
grams
Water
888
ml
Bloom
112
ml (30s)
Total time
3:30-4:00
minutes
Brew note: Balanced Chemex brew. Clean body with full flavor. If too sour → finer grind. If too bitter → coarser grind.
Medium-coarse (between table salt and sea salt) · 200-205°F (93-96°C) · Bloom 112ml for 30 seconds, then pour in stages
| Chemex | Water | Coffee (g) | Bloom (ml) | Ratio |
|---|---|---|---|---|
| 3-cup Chemex | 444 ml | 28 g | 56 ml | 1:16 |
| 6-cup Chemex | 888 ml | 56 g | 112 ml | 1:16 |
| 8-cup Chemex | 1184 ml | 74 g | 148 ml | 1:16 |
| 10-cup Chemex | 1480 ml | 93 g | 186 ml | 1:16 |
The Chemex filter is the defining variable. Bonded Chemex filters are dramatically thicker than the paper filters used in a V60 or Kalita Wave — roughly 20-30% heavier by weight. This thickness has two effects. First, the filter absorbs a significant portion of the coffee's oils, which is why Chemex coffee has that distinctively clean, almost tea-like body. Second, the thicker paper slows the draw-down, meaning water spends more time in contact with the grounds.
This slower draw-down is why the grind needs to be coarser than a standard pour over. If you use a V60 grind in a Chemex, the combination of thick filter and fine grind creates a painfully slow brew — 6, 7, even 8 minutes — and the coffee will taste bitter, astringent, and over-extracted. Medium-coarse, closer to french press than to V60, keeps the total brew time in the 3:30-4:30 window where extraction is balanced.
The 1:16 ratio is slightly more dilute than the 1:15 used for drip, and that is intentional. Because the Chemex filter strips oils, the coffee has less body to carry flavor. A 1:15 ratio with the Chemex's clean profile can taste muddy — there's concentration without enough textural richness to support it. At 1:16 or 1:17, the brightness and clarity of the Chemex shine, and individual flavor notes (citrus, floral, stone fruit) become more legible.
Bloom (0:00-0:30). Pour twice the coffee weight in water (e.g., 56g coffee → 112ml water) in slow concentric circles, starting from the center and moving outward. Make sure all the grounds are saturated. Wait 30 seconds — you will see the bed rise and bubble as CO₂ escapes. This degassing step is critical. If you skip it, the trapped gas creates pockets in the coffee bed that water channels through unevenly.
First pour (0:30-1:30). Pour steadily in concentric circles, keeping the stream roughly the thickness of a pencil. Bring the water level to about two-thirds up the Chemex. Avoid pouring directly onto the filter walls — water that runs down the glass bypasses the coffee bed entirely and dilutes the brew without extracting anything.
Second pour (1:30-2:30). Once the water level drops to the top of the coffee bed, pour again in the same pattern. Maintain a consistent flow rate. The goal is keeping the slurry level relatively stable rather than letting it drain completely between pours. Complete drains cause uneven extraction — the top layer gets over-extracted while the bottom stays under.
Draw-down (2:30-4:00). After your final pour, let the remaining water draw through. If the total brew time exceeds 4:30, your grind is too fine — adjust coarser next time. If it finishes before 3:00, the grind is too coarse. The spent coffee bed should look flat and even, not cratered or channeled. A level bed means the water flowed through the grounds uniformly.
Chemex sizes are measured in 5oz cups — smaller than the 6oz cups used by most drip machines. A "6-cup" Chemex makes 30oz of coffee, which fills roughly two large mugs or three smaller cups. The 3-cup model is a single-serving brewer, the 8-cup handles a small group, and the 10-cup is for entertaining or heavy coffee households.
Unlike moka pots, you can absolutely brew a partial batch in a Chemex. If you have a 6-cup but only want one mug, use the single-serve ratio (about 28g coffee to 450ml water) and follow the same pour technique. The brew will be slightly different — faster draw-down, slightly less heat retention — but the ratio math scales cleanly.
One practical note on the 3-cup Chemex: it uses a different, smaller filter than the 6, 8, and 10-cup models. The filters are not interchangeable. If you own a 3-cup, make sure you're ordering the half-moon or circular filters designed for that size — the standard Chemex squares won't fit properly and will fold unevenly, causing channeling.
Have a specific question? “How much coffee for my 34oz Bodum?” or “Why does my cold brew taste weak?”
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A 6-cup Chemex holds about 888ml of water. At the standard 1:16 ratio, use 56 grams of coffee (roughly 10 tablespoons). Bloom with 112ml of water for 30 seconds, then pour the remaining water in slow, concentric circles over 3:30 to 4:00 minutes.