Chemex & the thick filter

The Chemex looks like a carafe with opinions, but the machine is really the paper. Chemex-bonded filters are 20–30% heavier than standard cone papers. They trap nearly all the fines and most of the oils, and they drain slower — which produces the cleanest, most transparent cup in coffee: tea-like, luminous, with acidity in sharp focus.

That slower paper changes your recipe. Grind coarser than you would for a V60 — roughly 48–62 on the universal scale — or the heavy filter plus a fine bed will stall the brew into bitterness.