What is a percolation brewing method?

Percolation is an extraction method where water passes through the coffee by gravity (or under pressure) just once, without prolonged contact with the grounds. Filter coffee (V60, Chemex, electric drip, Kalita) and espresso are all percolation methods. It is the most widespread family of brewing methods in the world, as opposed to immersion methods where coffee steeps in water.

The term 'percolation' comes from the Latin percolatio (filtration by traversal). In the coffee context, it refers to all methods where water passes through a bed of coffee — carried by gravity in the case of manual or electric filters, or forced under pressure in the case of espresso. In all cases, water is in contact with the grounds only for the duration of the pass — a few seconds to a few minutes — without prolonged accumulation.

Percolation methods subdivide into two main categories: ambient-pressure methods (filters) and pressure methods (espresso). For manual filters, the main families are: the V60 (Hario), Chemex, Kalita Wave, Melitta, and Bee House. Despite their design differences, all function on the same principle: hot water poured over a bed of ground coffee, which flows by gravity through a filter (paper, metal or cloth) into a vessel.

The flavour quality of percolation methods is generally characterised by great aromatic clarity — paper filters retain oils and fine particles, producing a transparent coffee with beautiful aromatic expressiveness. This is why filter methods are preferred for tasting specialty coffees with fruity, floral or complex profiles: a washed Ethiopian Yirgacheffe expresses its jasmine and bergamot notes far better in a V60 than in a French press.

Percolation imposes a trade-off: by removing oils, it reduces body and mouthfeel. Filter coffees are lighter, drier in the mouth, but more aromatically precise. The electric drip machine (automatic filter machine) is the most widely used percolation method in Belgian and French households — but its variable water temperature and flow rate make it often less precise than manual filters. A surprising fact: a study published in the European Journal of Preventive Cardiology in 2020 (cohort of 508,747 Norwegian participants) showed that filter coffee was associated with lower cardiovascular mortality compared to unfiltered coffee (French press, boiled coffee) — precisely because paper filters retain the diterpenes responsible for a slight cholesterol increase.

Percolation methods: main families