With the percolator design, water is heated in a boiling pot with a removable lid, until the heated water is forced through a metal tube into a brew basket containing coffee. The extracted liquid drains from the brew basket, where it drips back into the pot.
This process is continually repeated during the brewing cycle until the liquid passing repeatedly through the grounds is sufficiently steeped. A clear sight chamber in the form of a transparent knob on the lid of the percolator enables the user to judge when the coffee has reached the proper color and strength.
