The French Press, called a plunger in the southern hemisphere and a cafetière in France, is a simple mechanism that gives me maximum control over the variables that make up my cup of coffee: water volume and temperature and weight of coffee. Quite simply, coarsely-ground beans are added into the French Press followed by hot water. The lid mechanism is fitted, the coffee grounds are left to steep for around 3-5 minutes and then I press the grounds to the bottom of the vessel allowing the mixture to be poured into my cup.
The French press method lets the coffee steep instead of being filtered, so more of the coffee’s oils are released into the water. As I wrote a few weeks ago, it’s these oils that make the coffee taste richer and better. The Press method adds no impurities, which usually happens with filters. Using a French Press means there is only hot water and freshly-ground coffee being poured into your cup. All of the ground coffee is saturated so a maximum amount of oil, and therefore flavour, is released. Drip and filter mechanisms can’t create maximum saturation so drip and filter coffee can’t be as rich as coffee made with a French Press.
Most significantly, a French Press allows me to control the temperature and volume of water as well as the quantity of coffee going into the mixture. It’s OK to be a science geek and experiment with different water temperatures and volumes and different quantities (weights) of coffee grounds. I do and I make notes like a coffee scientist and I’m careful to use exact volumes and weights and temperatures. I weigh the coffee because different varieties have different densities and weight is more accurate than say the number of beans or spoonfuls. African coffees tend to be denser than South American coffee and this density difference means measuring the coffee by volume won’t be as accurate and therefore as consistent as measuring it by weight.
The remaining variable is the time to leave the ground coffee to steep in the hot water. After one minute of saturating or steeping, the grounds have usually floated to the surface so I stir the mixture briefly to maximise the exposure to the hot water. The goal is to release the maximum amount of oil from the grounds. After 2-3 more minutes of steeping, I press the mixture and then pour the coffee.
If I use the same volume of water and vary the weight of coffee, the water temperature, and the time taken to saturate the grounds, I can definitely taste a difference Adjusting the variables till I achieve the perfect flavour is the science of the French Press. And when I get it right, the coffee is wonderful and rich and satisfying and… perfect.