The Chemex 3 Cup is the single-serve member of the Chemex family, holding around 450 ml. In practice that is one generous mug or two small cups, which makes it the right size for people who love the Chemex's clean profile but brew mostly for themselves.
Because the carafe is narrower and the bed of coffee smaller, the 3 Cup brews faster and cools faster than its larger siblings. Keep the ratio close to 1:15 — about 22 to 25 g of coffee to 330 to 375 g of water — and aim for a medium-coarse grind slightly finer than you would use on a 6 Cup. Water at 94–96 °C, a 30-second bloom, and two or three confident pours give a total brew time between 3:00 and 4:00.
The cup profile is the same transparency and delicate aromatics the Chemex is known for, concentrated into a single serving. Pre-warm the carafe and drink it fresh: thanks to its geometry, a 3 Cup holds heat less well than a 6 or an 8, so this is not the brewer for a long, slow breakfast.