How do coffee percolator work?

For stove-top percolators, the bottom of the stem (sitting on the bottom of the coffee pot) covers a fairly large proportion of the bottom of the pot. As the water boils, it changes from a liquid to a gas, forming bubbles. All of the small bubbles accumulated in the "catcher" on the bottom form larger bubbles with a greater diameter than the diameter of the stem.

For electrical percolators, the heating element below the wider portion of the stem at the bottom heats to a temperature greater than the boiling temperature of water.

When these large bubbles float to the top of the pump stem (or wider part of the stem that contains the heating element,) they push the water above them in the stem up and out of the stem. The pushed out water hits the top of the pot and drips back onto the coffee basket. The water then seeps through the coffee and back into the pot.

It's all about fluid dynamics!

Hi Kevin,

ercolator is traditionally a type of pot used to prepare coffee. In the coffee making process of the percolator, water passes through the coffee grounds and separates the coffee soluble ingredients that provide aroma, color and taste to the coffee. Percolators are easy to use.