Chemex Brewing Guide: Method, Ratios and Everything You Need to Know
The Chemex looks like a chemistry flask and brews coffee like one too — slowly, deliberately, and with the kind of clarity that makes you wonder what's been hiding in your cup all this time. Designed in 1941 by German chemist Peter Schlumbohm, it's barely changed since. It didn't need to — the design is good enough to live in the Museum of Modern Art's permanent collection.
This Chemex brewing guide covers what makes the brewer different from every other pour-over, the ratios and grind that actually work, how to fold the filter properly, and why it's particularly well-suited to light roasts. Whether you're brewing one cup or six, the principles below are the same.
What the Chemex Actually Does Differently
Two things separate the Chemex from a V60 or Kalita Wave: the filter, and the shape.
The filters are about 20–30% thicker than standard pour-over papers. That extra density doesn't just slow flow — it absorbs more of the oils and micro-fines that pass through thinner filters. The result is an exceptionally clean, almost tea-like cup. Body is light. Sediment is essentially zero. Acidity is bright but never harsh.
The hourglass shape combines the brewing vessel and the carafe in one piece of glass. Coffee brews directly into the bottom chamber, where it can stay warm for a good while before serving. The wide cone at the top gives you space to pour without rushing, and the air channel down one side of the spout vents the filter as the brew drains — which is why the Chemex can handle larger batches without the bed clogging.
If you've been brewing on a V60 and your cup feels too dense or oily, the Chemex is the answer. If you find Chemex coffee too thin, the V60 will give you what you're missing. They're complementary, not competitive — see our V60 vs Chemex comparison for a direct breakdown.
Why Chemex Suits Light Roasts
Light roasts contain delicate floral, fruity, and acidic notes that thinner filters and faster brewers can muddle. The Chemex's slow drawdown and high-absorption filter let those flavors come through with extreme clarity. A washed Ethiopian or a high-grown Kenyan brewed on a Chemex will taste cleaner and brighter than almost any other method.
Dark roasts work too, but you lose some of the oily, syrupy body that makes a dark roast feel rich. If you only drink dark roast, a French press or AeroPress will likely make you happier. For everything else — especially single-origin light and medium roasts — the Chemex is hard to beat.
What You Need
- A Chemex (the 3-cup, 6-cup, and 8-cup are most common; "cup" here means about 5 fl oz)
- Chemex bonded filters (square or pre-folded circles — both work)
- A burr grinder
- A gooseneck kettle
- A digital scale
- A timer
- Fresh, whole-bean coffee
- Filtered water
Ratio and Quantities
Chemex brews best at 1:15 to 1:17 — slightly leaner than a V60 because the thicker filter slows extraction and the larger bed needs a bit more water to flow evenly.
Useful starting points:
- 1 cup: 25g coffee to 400g water
- 2 cups: 35g coffee to 525g water
- 4 cups: 50g coffee to 800g water
- 6 cups: 70g coffee to 1,120g water
Stick with 1:16 as a default and adjust from there. These ratios sit comfortably inside the Specialty Coffee Association's recommended brewing window for extraction yield and strength. Our coffee-to-water ratio guide goes deeper on why and when to shift.
Grind Size
Medium-coarse — noticeably coarser than V60. Think kosher salt rather than table salt. Because Chemex filters slow flow, a finer grind will choke the bed and run for 6–8 minutes, giving you a bitter, over-extracted cup.
If your brew is taking much longer than 4–4.5 minutes, coarsen the grind. If it's running through in under 3 minutes, go finer.
Water Temperature
94–96°C (200–205°F). The Chemex can take heat better than a V60 because the thicker filter and slower flow buffer the extraction. For light roasts, push to the upper end. For darker roasts, drop slightly.
How to Fold the Filter
This part trips people up. Chemex squares fold into a cone with three layers on one side and one on the other.
1. Take the square filter and fold it in half, then in half again, so you have a small square. 2. Open one side into a cone — three folded layers should sit against one wall, one layer against the other. 3. The three-layer side goes against the spout. This braces the filter against the air channel, lets it vent properly, and stops it from collapsing inward when you pour.
Pre-folded round filters are easier and produce the same cup. Either way, rinse the filter thoroughly with hot water before brewing — Chemex papers can carry a strong paper taste if you skip the rinse.
The Brew, Step by Step
We'll use a 2-cup brew (35g coffee, 525g water) as the worked example. Scale up or down as needed.
1. Rinse and warm. Place the folded filter in the Chemex, three-layer side toward the spout. Rinse with hot water, swirling to warm the glass. Pour out the rinse water through the spout (the filter will stay in place).
2. Grind and add coffee. Grind 35g of coffee medium-coarse. Tip it into the filter and shake gently to level the bed. Place on your scale and zero.
3. Bloom. Start your timer. Pour 70g of water (double the coffee weight) in slow circles, saturating all the grounds. Wait 40–45 seconds. The bed will dome and bubble — fresh coffee releasing CO₂.
4. First main pour. At 0:45, pour slowly in concentric circles from center out to about 300g total. Keep your pour low and steady. Avoid the filter wall.
5. Second pour. When the water has dropped to around halfway down the bed (roughly 1:45–2:00), pour again up to 525g. Aim to finish pouring by 2:30–3:00.
6. Drawdown. Let the remaining water draw through the bed. Total brew time should land between 4:00 and 4:30 from first drop to last.
7. Lift and serve. Remove the filter, give the Chemex a swirl, and pour.
Scaling for 2–6 Cups
The Chemex is one of the few pour-overs that scales gracefully. The same method works whether you're brewing 35g or 70g of coffee — the air channel vents the filter so larger beds still drain evenly. A few notes for larger batches:
- Bloom for slightly longer (50–60 seconds) to let the bigger bed fully degas.
- Pour in three additions instead of two — bloom, then 40%, then 40% — to keep the bed agitated and the temperature stable.
- Allow more total time. A 6-cup brew may take 5–5.5 minutes from start to finish. That's normal.
For brewing for two specifically, our pour-over for two guide compares Chemex against doubling up V60s.
Troubleshooting
Brew is bitter or astringent? Likely over-extraction. Coarsen the grind, lower the temperature slightly, or check that your bloom is properly saturating all the grounds.
Brew is sour, thin, or watery? Under-extraction. Grind finer, raise the temperature, or extend the bloom by 10–15 seconds.
Filter collapses or clogs? You're either pouring too aggressively, the grind is too fine, or the filter wasn't folded with three layers toward the spout.
Cup tastes papery? Insufficient filter rinse. Use more hot water next time.
What's In The Cup Matters More
The Chemex's whole purpose is clarity. It strips a coffee down to its essential character and presents it without disguise. Which means a flat, stale coffee tastes exactly as flat and stale as it really is. There's no body to hide behind.
This is why the Chemex rewards good beans more than almost any other brewer. The coffees that genuinely come alive on a Chemex are the ones built for it — the bright, complex, freshly roasted single origins that win at competitions like the US Coffee Championships and the Golden Bean. Podium Coffee Club is built around those coffees. CNN Underscored called it "the best-tasting coffee subscription." Podium Gold ($24.50/month, 300g) and Podium Platinum ($29.50/month, 300g) are both whole bean, freshly roasted, and exactly the kind of coffee that makes a Chemex worth owning. For more on how we compare, see our guide to the best coffee subscriptions.
The rest of the variables — grind, ratio, technique — are covered in detail across our Ultimate Guide to Brewing Methods.
