The French press is frequently treated similarly to Jason Segal’s character in Forgetting Sarah Marshall. He’s the one you’re looking for, but people tend to flock to the flashy, volatile types like coffee-siphon-somethings or Russell Brands. The French press may lead to a coffee happily ever after, but it’s science nonetheless. Let’s take a closer look at how the French press works and How to Make the Best French Press Coffee at Home.
The French press, also known as the cafeteria or coffee press, is a cylinder-shaped beaker with a plunger typically made of glass but occasionally plastic or steel. Mesh makes up the plunger’s piston, which allows liquid to pass through but not larger coffee grounds.
The amount of brewed coffee you’re attempting to make and the coffee’s grind size will influence how quickly the water will flow through the coffee—and how long your total brew time will be—with some coffee-brewing techniques. This holds true for espresso, pour-over, and even drip brewing.
However, the relationships between brew yield, grind size, and brew time are not always direct. You can grind your coffee however you like, make a lot or a little coffee in a French press, and stop the brew in 10 seconds or 10 days. None of these factors has an impact on the others. This gives you a little more freedom when using a French press, though it doesn’t guarantee that the final beverage will taste great. In fact, perhaps you should refer to it as a “Freedom press” instead. Oh, forget it.
As you might remember from our discussion of the pour-over technique, I like to refer to the three general stages of coffee brewing wetting, dissolution, and diffusion.
The act of completely saturating the coffee grounds is known as wetting. Each of the cells that make up coffee grounds contains some of the coffee solids that we want to extract. Wetting those cells in fresh coffee causes the carbon dioxide gas that was previously trap there to be released, which we refer to as a “bloom.”
The second step, dissolution, involves combining our solvent, hot water, with the solids that will comprise the coffee component of our beverage. Diffusion is the last step, where the coffee water concentrate moves from the grounds into the surrounding liquid. Although dissolution and diffusion are frequently combining under the umbrella term “extraction,” I believe it is beneficial to view those processes independently.
The liquid surrounding the coffee grounds is continuously refill with new, hot water during drip and pour-over brewing. This is crucial because the more pure the water in the area, the more effectively the osmotic pressure forces the coffee concentrate from our grounds. Conversely, those outer surfaces of the coffee grounds are extract more quickly when hot, clean water is constantly flowing over them. As a result, we have less time to brew before those outer surfaces are sufficiently extract to add unappealing, “over-extract” flavors to our brew. The key to making the best coffee is finding the perfect balance between maximizing the good flavors and minimizing the less-than-delicious ones.
“The energy-driving diffusion is reduced in our low-and-slow French press because more water isn’t added as you go, leading to a slower, more gradual brewing process.”
The environment for making coffee in the French press is quite different. The energy transfer during drip or pour-over brewing is accelerate by convective heat, which comes from flowing water, much like in a convection oven. Since you aren’t continuously adding water to our low-and-slow French press, the energy-driving diffusion is reduced, resulting in a slower, more gradual brewing process. The brewing process is ultimately more gentle, and the surface-over-extraction effect is less noticeable. All things considered, French press brewing is less fussy than most other techniques and can produce brews with richer flavors, deeper sweetness, and syrupy bodies.
French presses have mesh filters that do a good job of keeping the grounds in, but a small amount of fines, which resemble powdered coffee grounds, will slip through the filter and stay suspended in your brew. Avoid becoming overly distracted by those. The fines may give the impression of greater richness and viscosity.
Try It at Home!
Here is how I make excellent French press coffee on a basic level. You’ll need to experiment and adjust the variables a little, tasting your results before you settle on your ideal settings, as with all coffee brewing techniques. The good news is that compared to faster brew methods, the French press is considerably more forgiving.
To time your brew, keep a watch or stopwatch close at hand. One is probably hidden in the “Clock” app on your smartphone.
- Use your grinder’s coarsest setting, to begin with, a very coarse grind. The particles should position between the steel-cut oats and coarse salt. Make a note of your grind size so you can adjust it later: if your brew was weak, grind a little finer next time; if you’re tasting a lot of unpleasant, dish-raggy, over-extracted flavors, grind a little coarser next time. How much: There isn’t really a minimum amount that your French press will produce, but there is a maximum amount. Between 60 and 70 grams of coffee per liter of water (or a mass ratio between 1:16 and 1:14), is a good coffee-to-water ratio. Determine how much-brewed coffee you’ll need, then weigh the appropriate quantity of coffee.
- Prepare your clean brew water (filter it if necessary). Unless you have an insulated (or double-walled) press, you can pour your water into a French press immediately after it comes to a boil. In that case, you should wait about 30 seconds. It’s best to use water that is between 10 and 15 degrees cooler when brewing dark-roasted or decaf coffee.
- Set your timer to “3” and add the water: Some people prefer to add some water, stir, and then add the remaining liquid. Actually, it doesn’t matter. What you do after adding the water is what matters. The release of CO2 gas will cause your grounds to rise up and float on top of your water, so if you were to just sit back and wait out the rest of your brew time now, you would have a brew that was not fully extract. Recall the initial stage, “Wetting”? You should give your coffee and water mixture a gentle but thorough stir at around 30 to 45 seconds in because if you don’t have good wetting, you won’t have much of anything that follows. You’ll know when it’s safe to close the lid.
- This may sound very different from what you’ve heard before, but bear with me: aim for a brewing time of 6 to 8 minutes. “What? You might say, “I thought it was three to four minutes,” you might exclaim. You can brew in 3 to 4 minutes if you want, but you would need to grind much more finely to achieve good flavor results, and you wouldn’t be maximizing the benefits of the French press’s special features. See if you can get it right by trying 6 to 8 minutes with the coarse grind.
- It’s time to plunge when you’re ready to stop brewing. French press is a nice, slow, gentle brew, as I’ve already mentioned. Violently agitating your coffee grounds is a great way to ruin that niceness because it speeds up extraction right when the coffee has already given up the good stuff and the bitter and astringent negative flavors are on the verge of taking over. Drop gently. If the plunger starts to feel tight, move it back a few inches and plunge again. When you reach the bottom, your work is finish!
- Even though there won’t be much brewing after you’ve plunged your bed down firmly, it’s still best to pour off your entire beverage immediately to effectively stop the brewing process.