Boiling water in the lower bowl of the vacuum coffeemaker is forced into the upper chamber, where it mixes with the coffee and then filters back into the lower bowl. If using an electric vacuum coffeemaker, follow the manufacturer’s directions, using the water-to-coffee proportions listed here. Allow for every serving:

Measure water into the lower bowl. Place on the heat. Add the ground coffee to the upper bowl. (If your equipment has a vented stem—a small hole in the side of the tube above the hot water line—you can place the upper bowl on the coffeemaker and place the whole thing on the heat; if it does not have a vented stem, wait until the water is actively boiling before putting the upper bowl in place.) Insert the upper bowl into the lower one with a light twist to ensure a tight seal. When nearly all the water has risen into the upper bowl (some of it will always remain below), stir the water and coffee thoroughly. In 1 to 3 minutes (the finer the grind, the shorter the time), remove from the heat and allow the coffee to run back into the lower bowl.