How Does French Press Work ?

The French Press works by steeping coffee grounds and hot water in a beaker. Once the coffee is done steeping, a metal mesh filter is pressed to the bottom of the beaker which separates the coffee grounds from the liquid coffee destined for your mug. The metal mesh filter allows the natural oils found in coffee and fine particles to pass through it giving the coffee a thick body.

This process of steeping coffee and water together for an extended time is called immersion brewing because the coffee is immersed in the water as opposed to drip brewing where the water flows through the coffee grounds.

Since the coffee and water are mixed together it is easy to get a uniform extraction with immersion brewers. However, this method is vulnerable to over-extraction if the coffee is ground too small or the coffee and water are left to steep for too long

The French Press separates into two main parts:

1. The lid, plunger and filter

French Presses use a metal filter that allows natural oils and fine particles from the coffee beans to pass through into your cup. This is what gives French Press coffee its rich and hearty body compared to brewing methods that use a paper filter.

The filter is connected to a metal rod that passes through the top known as the plunger which is used to press the filter to the bottom of the beaker and earn the French Press the latter half of its name.

The lid fits onto the top of the beaker and the filter is sized to snugly slide into the beaker with enough pressure on the side walls to prevent coffee particles from sliding by when it's pressed.

2. The beaker, base and handle.

The beaker is usually made from glass but some models use plastic, metal or ceramic. Its purpose is to hold the coffee and water while it steeps and make it easy to pour the brewed coffee into your mug.

The configuration of the body and handle can vary depending on the materials used to make the French Press. We dive into these variations in the section about buying a french press.

The French Press is widely used because you do not need fancy equipment like a long-neck kettle, a supply of paper filters or any electricity to brew with it. The minimum ingredients to make French Press coffee are hot water, ground coffee and a French Press.

The quality of coffee you brew will significantly increase with a few additional tools. Using a burr coffee grinder to freshly grind your beans just before brewing will make the biggest impact. Once the coffee is ground it begins to oxidize and lose flavor which means pre-ground coffee is not an option if the goal is to make quality coffee.

A burr grinder will also produce a consistent grind with uniform particle sizes. This is especially important when making French Press coffee because the coffee grounds are steeped in the water for so long. If you have uneven particle sizes, like the ones produced by a blade grinder, the small particles will get over-extracted (bitter) and the large ones will be under-extracted.