You can indeed burn coffee and create an acrid brew if you use water that’s too hot. Even for coffee drinkers who like their coffee as hot as possible, brewing with boiling water is not a good idea. To ensure you’re using water at a perfect temperature, first bring it to a boil. Then, when it’s boiling, take it off the heat source and let it cool for 30 to 45 seconds. Your water should have come down to 205 degrees by then, which is in a perfect window to begin brewing, though you’ll be fine within a few degrees off 200 on either side. If you’re willing to invest in some new equipment to make this process easier, there are also plenty of electric kettles on the market with temperature controls, so you can program the kettle to 200 and have the kettle hold it there until you’re ready to start brewing.
Like any coffee brewer (or really anything in your kitchen), you’ll want to keep your French press clean. Between brews, simple dish soap and hot water is more than enough, and, if you want to save yourself the effort, most French press models are dishwasher safe (though if yours has a large number of plastic parts or unusually thin glass, you might want to double-check the packaging just to be safe). Regardless of your day-to-day cleaning method, you’ll want to do a monthly deep clean. In addition to any bacteria buildup that soap might not catch, this deep clean is important for getting rid of scale (also known as limescale), which is a layer of calcium carbonate that builds up in any device that constantly comes into contact with water — especially in regions with harder water. There are commercial descaling products you can use, but you’ll also be fine using a 1:1 mixture of hot water and distilled white vinegar. Just fill your French press carafe with that mixture and insert your plunger so that it’s submerged. Leave it for four minutes, and then clean your French press thoroughly with hot water to get that vinegar taste and aroma out of there.
Yes, you can make your cold brew recipe in a French press with relatively easy cleanup. Using about an 8:1 ratio of water to coffee instead of 15:1, because cold brew is traditionally brewed stronger to account for ice. If you want to simplify, just use twice as much coffee as you normally would. Use room temperature or cold water instead of hot water, and extend the brew time from four minutes to 12 to 18 hours. Other than that, the grind size and technique are the same. Just put your coarse ground coffee and water in the French press and leave it at room temperature out of direct sunlight. Cover it with a lid, but don’t plunge — you want the coffee to keep extracting and stay in contact with the water during the entire brewing process. When you’re ready to drink, just plunge all the way down and strain. The stainless steel filter will leave a little more sediment in your cold brew than some other filtration methods, but the flavors will be just as delicious. The principles that make a French press great for coffee also make it a really useful device for separating any kind of infusion. You can use it for tea, or to infuse water with cucumber, lemon, and spirits with herbs, citrus peels, and spices. (Ones with less flavor like vodka are a great blank canvas!)