Drip coffee
[1][2] Water seeps through the ground coffee, absorbing its constituent chemical compounds, and then passes through a filter.
Commercial paper coffee filters were invented in Germany by Melitta Bentz in 1908[3][4] and are commonly used for drip brew all over the world.
Permanent filters are also common, made of thin perforated metal sheets, fine plastic mesh, porous ceramics or glazed porcelain sieves that restrain the grounds but allow the coffee to pass, thus eliminating the need to have to purchase separate filters which sometimes cannot be found in some parts of the world.
A mathematical argument has been made that delivering comparable strength in two cups of coffee is nearly achieved using a Thue–Morse sequence of pours.
[12] In South India, filter coffee brewed at home is known as Kaapi and is a part of local culture.
It is common in South India and Louisiana to add chicory to coffee to give it a unique taste and flavour.
[14][15] The quality of the resulting coffee is extremely dependent on the technique of the user, with pour-over brewing being a popular method used in the World Brewers Cup.
This pre-wetting, called blooming,[nb 1] will cause carbon dioxide to be released in bubbles or foam from the coffee grounds and helps to improve the taste.
There also exist small, portable, single-serving drip brew makers that only hold the filter and rest on top of a mug or cup, making them a popular option for backcountry campers and hikers.
Manual drip coffee makers include the so-called French drip coffee pot (invented in 1795 by François Antoine Henri Descroizilles [de] and manufactured by a metal-smith in Rouen,[17][18] then popularized by bishop Jean-Baptiste de Belloy[17][18] for why it became known as Cafetière du Belloy [de] in Paris since 1800[19][20] to the point that it was sometimes incorrectly attributed to the bishop himself[21][20]), the Grègue [fr] (café grègue, café coulé, etc.
Around 1895, skyblue enameled metal coffee pots named Madam Blå [da] were introduced in Denmark by Glud & Marstrand.
[32][33] In contrast to French drip coffee pots which feature round holes, they all use a special double-layered cross-slitted strainer made from through-glazed porcelain.
A thermostat attached to the heating element turns off the heating element as needed to prevent overheating the water in the metal tube (overheating would produce only steam in the supply hose), then turns back on when the water cools below a certain threshold.
[citation needed] Throughout the latter part of the 20th century, a number of inventors patented various coffeemaker designs using an automated form of the drip brew method.
