Processing · decaffeination
CO₂ decaffeination uses supercritical carbon dioxide to dissolve caffeine from green coffee, keeping flavor and leaving no residue. Why it is mostly industrial.
CO₂ decaffeination uses carbon dioxide held above its critical point, where it behaves as both a liquid and a gas.
Moistened green coffee is placed in a pressure vessel and supercritical CO₂ is circulated through it at very high pressure. The CO₂ selectively dissolves caffeine while leaving most larger flavor molecules behind.
The caffeine is then separated and the CO₂ recycled.
Selectivity. CO₂ is unusually good at targeting caffeine specifically, so flavor retention is excellent — arguably the best of the commercial methods.
No solvent residue. The CO₂ simply evaporates.
Cost. The pressure vessels are expensive and only economic at industrial scale, which is why CO₂ decaf tends to appear in large-volume commercial coffee rather than in small specialty lots.
Bags rarely specify. If a decaf is from a specialty roaster it is most likely Swiss Water or EA; if it is a supermarket brand it may well be CO₂ or a solvent method.
Grind coarser and re-dial. Decaffeinated beans are drier and more brittle than regular beans, so they grind finer at the same setting and extract faster; start a step or two coarser and adjust by taste. Decaffeinated beans are drier and more brittle than regular beans, so they grind finer at the same setting and extract faster; start a step or two coarser and adjust by taste.
The equipment this actually requires — not a shopping list, the shortest route to doing it properly.
60° cone · spiral ribs · 1–4 cups
The most transparent cup you can brew for twenty dollars, and the least forgiving. Ceramic holds heat where plastic does not — and the open bottom means your pour, not the dripper, decides the coffee.
Best for: Someone who wants to taste what a single-origin coffee is actually doing.
64 mm (2.52 in) flat burr · filter only · single dose
64 mm (2.52 in) flat burrs, near-zero retention and a footprint the size of a mug, built for filter and honest about not doing espresso. For pour-over it is the clearest grind you can buy at this price.
Best for: V60, Chemex, AeroPress and batch brewing, where clarity is the whole point.
0.9 L · ±1 °C (±1.8 °F) hold · counterbalanced gooseneck
The best-pouring kettle sold, and the hold function matters more than the thermometer. Expensive for boiling water — but if you brew pour-over daily, it is the accessory that most improves the cup.
Best for: Daily pour-over, where flow rate is the variable you are trying to control.
