Because the coffee grounds remain in direct contact with the brewing water and the grounds are filtered from the water via a mesh instead of a paper filter, coffee brewed with the cafetiere captures more of the coffee's flavour and essential oils, which would become trapped in a traditional drip brew machine's paper filters. As with drip-brewed coffee, cafetiere coffee can be brewed to any strength by adjusting the amount of ground coffee which is brewed. If the used grounds remain in the drink after brewing, French pressed coffee left to stand can become "bitter", though this is an effect that many users of cafetiere consider beneficial. For a 1⁄2-litre (0.11 imp gal; 0.13 US gal) cafetiere, the contents are considered spoiled, by some reports, after around 20 minutes. Other approaches consider a brew period that may extend to hours as a method of superior production.
If you’re shopping for coffee at the grocery store, “check the roast date, rather than the ‘best by’ date,” says Awan. With mass market roasters, the “best by” date can obfuscate the window in which coffee beans are at their best: about 4 days after roasting, when some, but not all, of the carbon dioxide has escaped from the beans. (Too much carbon dioxide captured within beans tends to create uneven extraction, as the gas escapes — this is what pre-infusing tries to counter. Conversely, too little carbon dioxide in the bean can lead to a loss of flavor.)
‡Pre-Infusing: Pre-infusing is a technique where the dry coffee grounds are initially saturated with hot water, allowing a “bloom” of carbon dioxide to escape. This 45-second(ish) process puts hot water into contact with more surface area around each ground throughout the brewing process, as it’s no longer competing with the escaping gas bubbles. It can improve the quality of the final product, since this more uniform contact creates a more even extraction. It’s a feature that six of the 10 pots we tested incorporated into their designs — as well as all four of our top picks.
Clean the inside of your machine by running water through it. Each machine will have a slightly different process, and some manufacturers provide tips and suggestions in user manuals. CoffeeLounge and other suggest mixing 2 oz. of vinegar in 20 oz. of water every now and then to clean out the machine even more thoroughly. After you use vinegar, though, be sure to rinse it three times with water to avoid any lingering vinegar taste in your next espresso.
Let’s circle back to that extra-long brew time. There are two factors that didn’t make it an automatic “no” for us. The first is that the OXO On 12-Cup is programmable. Like our experts say, grinding coffee in advance isn’t going to make the most perfect cup of coffee. But the fact that you can program the machine’s “wake-up time” to start brewing and have coffee ready when you are takes the sting out of the wait.