The variables behind a great cup of filtered coffee

Brewing an exceptional filtered coffee doesn't come down to a miracle method — it comes down to understanding how four extraction variables interact.

Grind size

A finer grind increases the contact surface between water and coffee, speeding up extraction. Too fine, and the result turns bitter and astringent; too coarse, and the cup turns flat and acidic.

Water temperature

Between 90°C and 96°C is the range where most desirable compounds dissolve in a balanced way. Below it, extraction stays incomplete; above it, bitter compounds get pulled out prematurely.

Contact time

Every method (V60, Chemex, French press) has its own target time. What matters isn't memorizing a number — it's understanding that time and grind always adjust together.

Coffee-to-water ratio

A typical ratio sits around 1:15 to 1:17. Changing it doesn't just dilute or concentrate the drink — it changes how complete the extraction is at a given grind and time.

Mastering these four variables, rather than just following a recipe, is what separates someone who makes coffee from someone who actually understands it.