Chemex

The Chemex is one of those rare objects that belongs equally in a kitchen and a museum. Designed in 1941 by Peter Schlumbohm, a German chemist living in New York, it was born from Bauhaus principles: form follows function, nothing is superfluous. The hourglass flask, the wood collar, the leather tie. It has been in the permanent collection of the Museum of Modern Art since 1944 and in the Smithsonian Institution. The Illinois Institute of Technology named it one of the best-designed products of modern times.

Schlumbohm’s background as a chemist informed everything about the design. He looked at laboratory glassware — the borosilicate beakers, the conical funnels — and saw the same shapes coffee needed. He held a US patent for the design and spent years defending it against imitators. The result was a brewer that has remained essentially unchanged in 80 years, because Schlumbohm got it right the first time.

But the Chemex is not a display piece. It is a serious brewer, and its secret weapon is the filter. Chemex bonded filters are 20–30% thicker than standard pour-over filters. That thickness removes more oils and micro-fines from the brew, producing a cup with extraordinary clarity. Bright acids shine. Delicate florals and fruit notes emerge without the muting effect of body and oils. If the V60 is a magnifying glass, the Chemex is a microscope.

What the Chemex Does Differently

Both the Chemex and the V60 are pour-over drippers that use paper filters and gravity. The differences are meaningful. The Chemex filter is substantially thicker, removing more of the lipids — cafestol and kahweol — and fine particles that give other pour-overs their slight body and texture. The result is a lighter-bodied, cleaner-mouthfeel cup that sits in the 1.10–1.30% TDS range at proper 18–20% extraction yield.

The Chemex is also designed for larger batches, typically 500ml and up. The V60 excels at single cups; the Chemex is the natural choice when brewing for two or more. The thicker filter slows drainage, so the Chemex uses a coarser grind than the V60 — medium-coarse rather than medium-fine. Chemex cups tend toward bright, tea-like, and delicate. V60 cups carry slightly more body and texture while still being clean. Neither is better; they highlight different aspects of the same coffee. See the brewing comparison tool to explore how these methods stack up side by side.

Water quality shapes the Chemex cup noticeably. The ultra-clean filtration means mineral composition comes through directly. Aim for filtered water in the 75–150 ppm TDS range. For a deeper look at how water chemistry affects your brew, see our water chemistry guide. To dial in your exact dose for any batch size, use the CoffeeBase brew calculator.

Instructions

1. Fold and place the filter. Open the Chemex bonded filter into a cone shape. One side will have three layers, the other side one layer. Place the filter in the Chemex with the three-layer side facing the pouring spout. This is essential: the triple layer reinforces the front where the filter could otherwise collapse, and the spout channel allows air to escape during brewing. Getting this backwards is one of the most common Chemex errors.

2. Rinse the filter thoroughly. Pour hot water through the filter, wetting it completely. This removes the papery taste that Chemex filters can impart if unrinsed — more noticeable than with thinner filters due to the extra material. Spend a good 15–20 seconds on the rinse, making sure every part of the filter is wet. Pour out the rinse water through the spout.

3. Dose and grind. Weigh 30–34g of coffee. Grind to a medium-coarse consistency, about the size of kosher salt or raw sugar. This is coarser than V60 but finer than French press. Add the grounds to the rinsed filter.

4. Bloom (0:00–0:45). Start your timer and pour about 60–70g of water over the grounds in a slow spiral, saturating everything evenly. Let the coffee degas for 45 seconds. Fresh coffee will dome up and bubble vigorously. This bloom allows CO2 to escape so the subsequent pours extract evenly. For more on what happens chemically during this phase, see our extraction science guide.

5. First pulse pour (0:45–1:30). Pour in slow concentric circles, adding water until the total reaches about 250g — half your total. Keep the pour steady and avoid the filter walls. Pause and let the water level drop about an inch below the rim of the grounds.

6. Second pulse pour (1:30–2:30). Pour again in the same pattern until you reach 400g. Pause again and let the level drop.

7. Final pour (2:30–3:00). Add the remaining water to reach 500g total. Maintain the same gentle, circular motion.

8. Drawdown (3:00–4:30). Let all the water drain through. The total brew time should be 3:30–4:30. If it runs significantly longer, your grind is too fine. If faster, too coarse.

9. Remove and serve. Lift out the filter with the spent grounds and discard. The Chemex itself is your server. Pour and enjoy.

The Pulse Pour Technique

Unlike the continuous pour used in many V60 methods, the Chemex benefits from pulse pouring: adding water in stages with brief pauses between them. The thicker filter drains more slowly, and continuous pouring can cause the water level to rise too high, creating uneven extraction as water sits above the coffee bed. Pulse pouring keeps the water level manageable and creates gentle agitation each time fresh water is added, which promotes even extraction. Three to four pulses across the total brew is the sweet spot — each pulse should take 15–20 seconds of pouring, followed by a 20–30 second drain.

Troubleshooting

If your coffee tastes bitter, dry, or harsh, the extraction is too high. Try grinding coarser, reducing your water temperature by 2–3°C, or shortening the total brew time by pouring more aggressively (while keeping the technique clean). The Chemex’s long brew time can over-extract dark and medium-dark roasts — drop your temperature to 90–92°C for anything roasted past medium. If your coffee tastes sour, sharp, or thin, the extraction is too low. Grind slightly finer or raise your water temperature. A total brew time significantly under 3:30 usually indicates the grind is too coarse. If your drawdown stalls or takes longer than 5 minutes, the filter orientation is likely wrong (three-layer side should face the spout), or the grind is far too fine.

Common Mistakes

Wrong filter orientation is the single most consequential error in Chemex brewing. The three-layer side must face the spout. If reversed, the single layer can collapse into the spout channel, blocking airflow and stalling the brew. You will get a slow, over-extracted, bitter cup. Grinding too fine is the second common mistake: the thick Chemex filter already slows flow dramatically, and using a V60-fine grind will choke the brew, pushing your time well past 5 minutes. Start at medium-coarse and adjust gradually.

Not rinsing the filter produces a noticeable papery taste in the cup — Chemex filters are thick enough that this is genuinely distracting if you skip the rinse. And resist the urge to pour fast. The Chemex’s wide opening invites aggressive pours, but fast pouring creates channeling and uneven extraction just as it would with any pour-over. Use the same controlled gooseneck technique you would with a V60.

Pro Tips

After your final pour, a gentle swirl of the entire Chemex settles the bed and dislodges grounds from the walls. Scott Rao’s technique works beautifully with the Chemex’s wide cone. The Chemex excels with African coffees — the ultra-clean cup profile pairs brilliantly with the bright acidity and floral complexity of Ethiopian and Kenyan coffees. If you want to taste the blueberry in a natural-process Ethiopian, the Chemex will show it to you with more fidelity than almost any other brewer.

One of the Chemex’s best features is that it brews directly into its own elegant server. Brew 500ml for two people and serve at the table. The thick borosilicate glass retains heat reasonably well for 15–20 minutes. Chemex sells both square (folded) and circular pre-folded filters — both produce the same cup quality, so use whichever you find more convenient.

References

• Hoffmann, James. The World Atlas of Coffee. Mitchell Beazley, 2014.
• Rao, Scott. The Coffee Brewing Handbook. Scott Rao, 2009.
• Chemex Corporation. “Chemex Coffeemaker Original Instructions.” Chemex.com, 2022.
• Specialty Coffee Association. “Brewing Control Chart.” SCA Technical Standards, 2023.
• Barista Hustle. “Pulse Pouring and Extraction Evenness.” baristaHustle.com, 2020.
• Museum of Modern Art. “Chemex Coffeemaker, 1941.” MoMA Collection, permanent collection entry.
• Hoffmann, James. “How to Make the Best Filter Coffee.” jamesHoffmann.co.uk, 2022.