The first thing that may come to mind is old west cowboy coffee percolators, but percolation in principle describes the brewing process underpinning a coffee percolator, and a variety of other popular brewing methods. Simply put, percolation is where water is passes through ground coffee via gravity. Usually there is a filter paper, or mesh, in between the coffee and collection vessel.
Perhaps the most simple brewing principle, actually allows plenty of variation in technique in terms of how you pour the the water into the coffee. You are effectively working with gravity, so the direction in which you pour coffee is crucial to achieving a uniform brew. Pouring too much in one direction can cause channelling; a single hole in the bed of coffee, which over extracts in one area, causing bitterness and a general unpleasant taste in the brew. Please see our Hario V60 brewing guide for optimal techinque.
Whilst coffee culture in terms of roasting and brewing was booming in the 1800s, advances were being made to achieve high quality brews that were convenient and more domestic oriented. In 1819, the tinsmith Joseph-Henry-Marie invented the first modern percolator, which was later iterated and improved upon by inventor Hanson Goodrich 1889. The design is very straight forward. Heated water at the base of the put travels up through a funnel to the top of the pot. This water drips onto coffee in the filter basket and drips back into the coffee pot, and goes up the funnel again. Rinse and repeat until you achieve desired strength.
Unfortunately this is the fatal flaw of the percolator. There is no separation between the fresh water and the brewed coffee. You run brewed coffee through the grounds again, and apply direct surface contact just above the flame. You are effectively burning the coffee, developing and increasingly unpleasant bitterness and strength.
During the early 1900s, and in defiance of this brewing methodology, Amalie Auguste Melitta Bentz designed the first coffee filter papers. These pioneered a new way to enjoy coffee without the burnt or sediment characteristics prevailing at the time. Amalie put coffee in filter papers inside a punctured brass pot, poured hot water over it and into a cup. Voila!. The pour over has just been born.
Please see our guides on immersion and high pressure brewing, as well as what all of these mean together!