How Does a Coffee Percolator Work?
Many people brew their coffee in coffee pots called percolators. Inside a coffee percolator is a hollow stem. Sitting on top of the stem is a perforated basket for holding the ground coffee. When water in a coffee percolator boils, some of it changes to steam.
The steam rises through the hollow stem, and takes with it boiling water, which spurts out from the top of the stem. It percolates or filters back down through the ground coffee, picking up the flavor of the roasted and ground coffee beans.
The coffee is “perked” until the proper strength is reached. As the brew continually seeps through the grounds, the overall temperature of the liquid approaches boiling point, at which stage the “perking” action (the characteristic spurting sound the pot makes) stops, and the coffee is ready for drinking.
Coffee percolators once enjoyed great popularity but were supplanted in the early 1970s by automatic drip coffee makers. Percolators often expose the grounds to higher temperatures than other brewing methods, and may re-circulate already brewed coffee through the beans. As a result, coffee brewed with a percolator is susceptible to over-extraction.
Percolation may remove some of the volatile compounds in the beans, resulting in a pleasant aroma during brewing, but a less flavorsome cup. However, percolator enthusiasts praise the percolator’s hotter, more ‘robust’ coffee, and maintain that the potential pitfalls of this brewing method can be eliminated by careful control of the brewing process.