What is a Chemex?

The Chemex is an hourglass-shaped borosilicate glass coffeemaker invented in 1941 by German-born chemist Peter Schlumbohm in the United States. It uses a proprietary paper filter 20 to 30 % thicker than a standard filter, producing an exceptionally clean filter cup — oils, fines and sediment removed — with a delicate body and an aromatic clarity.

The Chemex was designed by Peter Schlumbohm, a German chemistry Ph.D. who emigrated to New York and filed the patent in 1941. Its hourglass silhouette with a wooden collar cinched by a leather lace has become an icon of industrial design: the vessel is in the permanent collections of the Museum of Modern Art in New York, the Philadelphia Museum of Art and the Smithsonian, and appears on the Illinois Institute of Technology's list of the 100 best-designed products of modern times.

The technical signature is the proprietary paper filter, 20 to 30 % thicker than a V60 or Kalita standard. That thickness traps more oils (the diterpenes cafestol and kahweol), fines and sediment, producing a very clean, almost tea-like cup. The filter comes in two shapes: pre-folded square, or circular. Correct folding — three layers against the spout, one on the opposite side — is key: it leaves an air channel between filter and wall for free drainage.

The Chemex is more forgiving than a V60 thanks to its restrictive filter: the slower flow produces a more even extraction even with a less precise grind, and the filter tends to buffer uneven pours. The trade-off is less expert control — you cannot dramatically reshape the cup just by modulating pour cadence. The reference recipe lands around 1:15 to 1:17, with a medium-coarse grind (coarser than V60, finer than French press) and a total brew time of 4 to 5 minutes.

It is sold in three sizes: 3-cup (15 oz), 6-cup (30 oz), 8-cup (40 oz) — plus a 10-cup. The 6-cup is the most common home size. Mind the variants: the Classic (without spout) requires removing the filter to pour, while the Handblown (with spout) lets you serve straight from the carafe. In Belgium, the Chemex is less common than the V60 in cafés, but popular in home brewing: its aesthetic is a recognised brunch centrepiece in open-plan Brabant kitchens.

Chemex — sizes and filters