The Chemex® was designed in 1941 by a chemist, not a barista, and it shows. It is one piece of borosilicate glass - the same glass as laboratory equipment - shaped so that the brewer and the carafe are the same object. It has been in the permanent collection of the Museum of Modern Art since 1944.
What makes it brew differently is not the shape, though. It is the filter.
The filter is the whole story
Chemex® filters are 20-30% heavier than a standard paper filter. That extra thickness traps almost all of the oils and the finest particles, and what comes out the other side is the cleanest cup in filter coffee - no sediment, no haze, no oily film on the surface.
The trade-off is honest: you lose some body. A Chemex® cup feels lighter in the mouth than the same coffee through a V60. What you gain is clarity. Delicate florals and fruit acidity that get buried under body in other brewers come through clearly here.
The thick filter also drains slowly, which is why the grind runs coarser than you might expect. Grind for a Chemex® like you would for a V60 and it will stall.
Fold the filter so the triple-layered side sits against the pouring spout. It supports the paper and keeps the channel open so air can escape while the coffee drains.
The ratio
Our house recipe is 20 g of coffee to 300 g of water for one, and 40 g to 600 g for two - a touch stronger than a standard 1:16, because the thick filter holds back some of the extraction.
| Cups | Coffee | Water | Target time |
|---|---|---|---|
| One | 20 g | 300 g | 3:00 |
| Two | 40 g | 600 g | 4:00 |
| Three | 55 g | 850 g | 4:30-5:00 |
The workable range is 1:15 to 1:18. Stay at the strong end if you like a fuller cup, move towards 1:18 for lighter, more delicate coffees.
Grind, water and technique
Grind
Medium-coarse, like rough sand. Coarser than a V60, finer than a French press. If your brew is drying up before 2:30, go coarser; if it is still dripping past 4:30, go finer. A burr grinder is not optional here - fines are what clog a thick filter, and blade grinders produce them in quantity.
Water
94 ºC. The Chemex® is a large, thick vessel that pulls heat out of the brew, so start at the top of the filter range - the preheat from rinsing the filter matters more here than on any other brewer.
Pouring
Bloom with about 50 g of water and give it 30-45 seconds. Then pour in slow, continuous spirals, keeping the water level well below the top of the paper. Because the cone is deep, it is easy to let water run down the wall and bypass the coffee entirely.
Do not stir the bed. The Chemex® rewards a gentle, even pour more than any manipulation.
Troubleshooting
| Problem | Likely cause | Fix |
|---|---|---|
| Stalls, takes over 5 minutes | Grind too fine, or filter folded wrong | Grind coarser; check the triple layer faces the spout |
| Drains in under 2:30 | Grind too coarse | Grind one step finer |
| Tastes thin and papery | Filter not rinsed | Always rinse with hot water first |
| Sour and sharp | Under-extracted | Grind finer or extend the pour |
| Bitter and dry | Over-extracted | Grind coarser or lower to 92 ºC |
| Uneven, patchy flavour | Water bypassing down the wall | Keep the pour inside the coffee bed |
Cleaning and care
Rinse the glass with hot water straight after brewing - coffee oils are far easier to remove before they cool and set. The wood collar and leather tie come off, and should stay off in the dishwasher.
The glass is dishwasher safe. The collar is not. A stained Chemex® can be cleared with a soak of hot water and a scoop of coffee-equipment cleaner, or a denture tablet in an emergency.
Which coffee to use
The Chemex® is at its best with light to medium roasts that have something delicate to say - washed Ethiopians, high-grown Central Americans, anything floral or citric. The clean cup gives those notes room that a heavier brewer would crowd out.
Dark roasts work, but the clarity that makes this brewer special is largely wasted on them. Browse our filter coffees, or let the subscription pick for you.
Chemex® questions, answered
What grind size for Chemex®?
Medium-coarse, like rough sand - noticeably coarser than a V60. The thick Chemex® filter drains slowly, so a finer grind will stall the brew and over-extract it.
What is the Chemex® coffee-to-water ratio?
Our house recipe is 20 g of coffee to 300 g of water for one cup, 40 g to 600 g for two. The usable range is 1:15 to 1:18 depending on how strong you like it.
Can I use normal paper filters in a Chemex®?
You can, but you lose what makes it a Chemex®. The proprietary filters are 20-30% thicker, and that thickness is the reason the cup is so clean. A thinner filter brews faster and tastes closer to a V60.
How long should a Chemex® brew take?
About 3 minutes for a single cup and 4 minutes for two, from the start of the bloom to the last drips. Over 5 minutes means your grind is too fine or the filter is folded wrong.
Which way does the Chemex® filter fold go?
The triple-layered side goes against the pouring spout. It holds the paper open so air can escape while the coffee drains - fold it the other way and the brew slows to a crawl.
Is the Chemex® dishwasher safe?
The glass is. Remove the wooden collar and leather tie first - those should be washed by hand, or not at all.
Why is my Chemex® coffee weak?
Usually bypass: water poured down the side of the filter instead of through the coffee bed. Keep every pour inside the bed, and check you are actually weighing 20 g of coffee rather than using a scoop.
Keep going
If the Chemex® cup is too light for you, the V60 gives you more body and more control per cup. If you want the opposite - full body, no paper at all - go to the French press.
Whichever brewer you land on, start with coffee that was roasted recently. We roast to order in Lisbon and ship within 24-48 hours - see what is on the shelf right now.
