A coffee percolator is a type of pot used to brew coffee. The name stems from the word "percolate" which means to cause (a solvent) to pass through a permeable substance especially for extracting a soluble constituent.In the case of coffee-brewing the solvent is water, the permeable substance is the coffee grounds, and the soluble constituents are the chemical compounds that give coffee its color, taste, and aroma. There are two basic types of percolator:
* One which forces boiling water under pressure through the grounds into a separate chamber; and
* One which continually cycles the boiling brew through the grounds using gravity until the required strength is reached.
Coffee percolators once enjoyed great popularity but were supplanted in the early 1970s by automatic drip coffee makers, and more recently by the French press, as well as a renewed interest in espresso coffee. Percolators often expose the grounds to higher temperatures than other brewing methods, and may recirculate already brewed coffee through the beans. As a result, coffee brewed with a percolator is susceptible to over-extraction.In addition, percolation may remove some of the volatile compounds in the beans. This results in a pleasant aroma during brewing, but a less flavourful 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.
Brewing process
A non-pressure driven percolator consists of a pot with a small chamber at the bottom which is placed closest to the heat source. A vertical tube leads from this chamber to the top of the percolator. Just below the upper end of this tube is a perforated chamber.
The desired quantity of water is poured into the water chamber of the pot and the desired amount of a fairly coarse-ground coffee is placed in the top chamber. It is important that the water level be below the bottom of the coffee chamber.
After the percolator is placed on the heat source (such as a range or stove), the temperature rises until the water in the bottom chamber boils. While some models may have a one-way aromalock valve at the bottom of the tube which forces some of the boiling water up the tube, most operate on the simple principle that the rising bubbles will force the liquid up the tube. The hot water is distributed at the top over the perforated lid of the coffee chamber. This water then seeps through the coffee grounds and leaves the coffee chamber through the bottom, dropping back into the lower half of the pot. The rest of the colder water at the bottom is meanwhile also forced up the tube, causing this whole cycle to repeat continually.
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. In a manual percolator it is important to remove or reduce the heat at this point (keeping in mind the adage "Coffee boiled is coffee spoiled"). Brewed coffee left on high heat for too long will acquire a bitter taste.
Some coffee percolators have an integral electric heating element, and should obviously never be used on a stove. Most of these automatically reduce the heat at the end of the brewing phase, keeping the coffee at drinking temperature but not boiling.
Inventor
The percolating coffee pot was invented by the American scientist and soldier Count Rumford, otherwise known as Sir Benjamin Thompson (March 26, 1753 – August 21, 1814). He invented a percolating coffee pot following his pioneering work with the Bavarian Army, where he improved the diet of the soldiers as well as their clothes. It was his abhorrence of alcohol and his dislike for tea that led him to promote the use of coffee for its stimulating benefits. For his efforts, in 1791, he was named a Count of the Holy Roman Empire, and granted the formal title of Reichsgraf von Rumford.
The first US patent for a coffee percolator was issued to James Mason of Franklin, MA, in 1865. An Illinois farmer named Hanson Goodrich is generally credited with patenting the modern U.S. stove-top percolator as it is known today, and was granted a patent on August 16, 1889. Goodrich's design could transform any standard coffee pot of the day into a stove-top percolator.
Usage
Percolators are often popular among campers and other outdoorsmen due to the ability to make coffee without electricity. Non-pressure percolators may also be used with paper filters.
Improvements
The method for making coffee in a percolator had changed very little since its introduction in the early part of the 20th century. However, in 1970 General Food Corporation introduced Max Pax, the first commercially available "ground coffee filter rings”. The Max Pax filters were named so as to compliment General Foods' Maxwell House coffee brand. The Max Pax coffee filter rings were designed for use in percolators, and each ring contained a pre-measured amount of coffee grounds that were sealed in a self-contained paper filter. The sealed rings resembled the shape of a doughnut, and the small hole in the middle of the ring enabled the coffee filter ring to be placed in the metal percolator basket around the protruding convection (percolator) tube.
Prior to the introduction of pre-measured self-contained ground coffee filter rings; fresh coffee grounds were measured out in scoopfuls and placed into the metal percolator basket. This process enabled small amounts of coffee grounds to leak into the fresh coffee. Additionally, the process left wet grounds in the percolator basket, which were very tedious to clean. The benefit of the Max Pax coffee filter rings was two-fold: First, because the amount of coffee contained in the rings was pre-measured, it negated the need to measure each scoop and then place it in the metal percolator basket. Second, the filter paper was strong enough to hold all the coffee grounds within the sealed paper. After use, the coffee filter ring could be easily removed from the basket and discarded. This saved the consumer from the tedious task of cleaning out the remaining wet coffee grounds from the percolator basket.
With the introduction of the electric drip coffee maker in the early 1970's, the popularity of percolators plummeted, and so did the market for the self-contained ground coffee filters. In 1976, General Foods discontinued the manufacture of Max Pax, and by the end of the decade, even generic ground coffee filter rings were no longer available on U.S. supermarket shelves.
Naming convention
There exists some controversy as to whether the Moka Pot may be referred to as a percolator. If common usage defines the word then it certainly must be accepted as a common name. Scientifically the term is also correct, with the problem boiling down to the question of "Can pressurised hot water be percolated through a medium?" If the answer is yes then the form of brewing which takes place in the Moka Pot (the forcing of steam-pressurized water through coffee grounds) can be considered a type of pressure-driven percolation and, therefore, the machine which causes it to happen can be termed a "percolator". So, strictly speaking, because the Moka Pot has a percolating compartment it can be referred to - mechanically - as a (machine which) percolates. This forcible driving of hot water through a coffee layer has been referred to as "percolation" in patents. The Moka Pot is described by Saveur as a juxtaposition of percolated coffee and espresso,which acknowledges that percolation is part of the espresso-making process in the Moka Pot. Whilst the Specialty Coffee Association of America recognises six basic methods of brewing (Steeping, Decoction, Percolation, Drip Filtration, Vacuum Filtration and Pressurised Infusion) the differentiation of "Percolation" and "Pressurised Infusion" does not negate the fact that percolation occurs in the Moka Pot (ie: water is filtered through coffee grounds).
