Is a French press immersion or filter?

It is immersion. All the coffee sits in all the water for the whole brew, and the mesh separates them at the end rather than filtering during extraction.

Why is pour over harder to get right than French press?

Because in percolation the grind controls flow as well as surface area, and water can find an uneven path through the bed. Immersion has neither problem, so it fails more predictably.

Does leaving a French press longer make it stronger?

Less than you would think. Full-immersion extraction approaches an equilibrium rather than rising indefinitely, so late minutes change the cup much less than the first ones did.

Which method makes clearer coffee?

A paper-filtered percolation brew is the clearest, because paper retains fines and oils. A metal-filtered immersion brew passes both into the cup, which gives more body and more sediment.

Two ways water meets coffee

Filter, immersion and what changes

Nearly every brewer is one of two things. Knowing which one you are holding tells you what to change when it goes wrong.

Immersion holds one body of water against the grounds for the whole brew. Percolation moves fresh water past the bed continuously, so the water meeting the coffee is always relatively unsaturated.

Immersion: one water, whole time

French press, cold brew, and the AeroPress in most recipes. Every particle sits in the same water for the whole brew, and extraction slows as that water approaches saturation. An equilibrium desorption model for full-immersion brewing models exactly this: full-immersion strength and yield approach an equilibrium rather than climbing without limit, which is why an extra minute in a French press changes less than you would expect.

Percolation: fresh water, always moving

V60, Chemex, batch drip, moka, espresso. Fresh water passes the bed continuously, so the concentration gradient stays steep and extraction keeps going. That makes percolation faster and more powerful — and much easier to push too far, and much more sensitive to how evenly the water travels.

What changes in practice

Grind. Immersion tolerates coarse; percolation needs the grind to control flow as well as surface area. Time. Immersion time is forgiving near the end; percolation time is set mostly by the grind, not chosen. Failure mode. An immersion brew that goes wrong is usually uniformly wrong. A percolation brew that goes wrong is often unevenly wrong, because water found a path — channelling — and part of the bed was barely touched.

Which to pick

If you want forgiving and repeatable with minimal technique, immersion. If you want clarity and a lever you can actually pull, percolation. If you want both on the same shelf, they are cheap enough that most people end up with one of each. The recipe library has authored baselines for both, and the timer runs them step by step.

The limit of this model

Real brewers blur the line. An AeroPress is immersion until you press, then briefly percolation. A moka pot is percolation under modest pressure. Treat immersion and percolation as the two ends of a spectrum that explains behaviour, not as a taxonomy that every device fits neatly into.