thumb|Ground coffee being poured into a paper filter inserted in a [[Chemex filter holder and caraffe]]

A coffee filter is a filter used for various coffee brewing methods including but not limited to drip coffee filtering. Filters made of paper (disposable), cloth (reusable), or plastic, metal or porcelain (permanent) are used.

Coffee filters are typically made up of filaments approximately 20 micrometres wide, which allow particles through that are less than approximately 10 to 15 micrometres.

Some baristas claim that paper filters exhibit a "paperish" taste introduced their (English: quick filter),

thumb|right|Fan- or boat-shaped coffee filter, made of unbleached paper

Patented in 1935, that is why other manufacturers use terms like coffee filter, paper filter, etc.

In 1936,), "102"<!-- measured bottom width on Melitta filter bag ca. 48 mm, edge length ca. 109 mm, angle ca. 57°. Other sources state: 115 mm https://web.archive.org/web/20230327082859/https://www.lofbergs.se/fragor-och-svar/faq/vad-betyder-kaffefilterbeteckningarna-102-och-1x4/ --> (for 3–6, or 4–8 cups<!-- à 1/6 litre --> or 10–15), "104" (for 15–25 or 30–60 cups), "112" (for 2 cups<!-- à 1/6 litre -->, with pot mount<!-- patented in 1955 and marketed up to the early 1960s -->) and "123"<!-- introduced in 1964, produced up to 1969/1972 https://web.archive.org/web/20170316133856/http://huelbach.de/aktion.htm -->). The system also included special types like tea filters "401" (1–6 cups, compatible with "101") and "402"<!-- introduced in 1932 according to Hempe --> (for 3–9 cups, compatible with "102") and the miniature filter "801"<!-- originally introduced in 1964, replicated in --> (for 1–2 or 1–3 small cups for children, or 1 normal cup A disadvantage of the system was that one had to pour water continuously or several times while the proper amount of necessary water could only be guessed.

Therefore, in 1963 Melitta developed a new fan- or boat-shaped filter system with corresponding "1×" nomenclature: In this system the filters are sized big enough so that the whole amount of water (except for the water needed for blooming) can be poured in one go. Consequently, the filter sizes "1×2",<!-- Introduced 1969 https://web.archive.org/web/20170316133856/http://huelbach.de/aktion.htm. Measured edge length ca. 93 mm. Other source states: 100 mm https://web.archive.org/web/20230327082859/https://www.lofbergs.se/fragor-och-svar/faq/vad-betyder-kaffefilterbeteckningarna-102-och-1x4/ --> "1×4",<!-- Introduced 1966 https://web.archive.org/web/20170316133856/http://huelbach.de/aktion.htm. Measured edge length ca. 118-120 mm, delta 25 mm. Other source states: 125 mm https://web.archive.org/web/20230327082859/https://www.lofbergs.se/fragor-och-svar/faq/vad-betyder-kaffefilterbeteckningarna-102-och-1x4/ --> "1×6"<!-- Introduced 1965 https://web.archive.org/web/20170316133856/http://huelbach.de/aktion.htm. Measured edge length ca. 143 mm, delta 25 mm. Other source states: 150 mm https://web.archive.org/web/20230327082859/https://www.lofbergs.se/fragor-och-svar/faq/vad-betyder-kaffefilterbeteckningarna-102-och-1x4/ --> and "1×10"<!-- Introduced 1966 https://web.archive.org/web/20170316133856/http://huelbach.de/aktion.htm. --><!-- Note: I have never seen "1x12", but the following source states that "1x12" existed as well --> result in 2, 4, 6, and 10 cups of coffee when filling the filter once. Since these filters only differ in height and have otherwise the exact same geometry, bottom width (about <!-- measured -->49&nbsp;mm<!-- 48–50 mm -->) and angle (about <!-- measured -->54°<!-- 53°–55° -->), the filter bags are interchangeable between filter holders of different sizes.

Both systems are still in use today in principle, but the sizes "101", "103", "104", "105", "106", "112", "123", "401", "402", ("502",) "801" and "1×10" are no longer manufactured.

Common in the US are fan- or boat-shaped filters "#0" (similar to "100"), "#1" (similar to "101"),

Hario began designing brewers in 1980; the V60 design was released in 2004.

The brewer received the Japanese Good Design Award in 2007

and is used by many of the winners in the World Brewers Cup. In partnership with 2013 World Barista Champion Pete Licata it was further developed into the Hario W60, a brewer with a flat-bottomed mesh filter, to "address the concern baristas have with 'flat bed' brewing".

The Hario Switch combines steeping with drip filtering.

Hario has cone-shaped paper filter bag sizes "01" (for 1 cup<!-- introduced when? -->), "02" (for 1–4 cups<!-- introduced when? -->) and "03" (for 1–6 cups<!-- introduced when? -->). circle filter rings (for percolators) "3&nbsp;&nbsp;in." (89&nbsp;mm), "164mm", "190mm"<!-- for container DE 5 https://web.archive.org/web/20240105023027/https://animo.eu/de-de/produkte/zubehor/filterpapier/rundfilterpapier -->, "203mm", "235mm", "240mm", "244mm", "256mm", "260mm"<!-- for container CE/CI 4, 6, 8, 10, DE 10 https://web.archive.org/web/20240105023027/https://animo.eu/de-de/produkte/zubehor/filterpapier/rundfilterpapier -->, "290mm", "330mm"<!-- for container CE/CI 12, 16, 20, 25, DE 20 https://web.archive.org/web/20240105023027/https://animo.eu/de-de/produkte/zubehor/filterpapier/rundfilterpapier -->, "400mm" and "440mm"<!-- for container DE 40 https://web.archive.org/web/20240105023027/https://animo.eu/de-de/produkte/zubehor/filterpapier/rundfilterpapier -->, prepleated flat-bottom basket filters "(A)250/90" (250&nbsp;mm<!-- top diameter -->/90&nbsp;mm<!-- bottom diameter -->, also known as "90/250"<!-- by Animo -->) and "(A)250/110" (250&nbsp;mm<!-- top diameter -->/110&nbsp;mm<!-- bottom diameter -->), roll filters "2004" as well as wrap filters (for percolators, 232&nbsp;× 241&nbsp;mm<!-- 9-1/8" × 9-1/2" -->). <!-- The former VEB Freiberger Zellstoff und Papierfabrik offered round disc filters in diameters 94 and 120 mm. Probably other sizes as well --> While some of them are still available today, most of them have fallen out of use for long.

A squarish pyramid filter Filtra "602" was available as well.

Other basket filter sizes include "101/317", "152/350", "152/457", "203/533" and "280/635".<!-- https://web.archive.org/web/20240105022845/https://animo.eu/de-de/produkte/zubehor/filterpapier/korbfilterpapier -->

Other round filter disks include 160&nbsp;mm<!-- for Animo 25P, 40P -->, 220&nbsp;mm<!-- for Animo 80P(VW), 100P(VW) -->, 195&nbsp;mm<!-- for Percostar 3, 5, 6 -->, 230&nbsp;mm<!-- for Percostar 12 und 15 --><!-- https://web.archive.org/web/20240105023027/https://animo.eu/de-de/produkte/zubehor/filterpapier/rundfilterpapier -->.

The Aeropress and Ceado Hoop<!-- 2023 --> use round paper filter disks with a diameter of c. 63&nbsp;mm<!-- some sources say 62 mm and 64 mm for the Aeropress, and 2.5" = 63.5 mm for the Hoop -->.

The German Tricolate coffee dripper<!-- 2018 --> uses round paper filter disks with a diameter of 88&nbsp;mm.

The Kanas-based NextLevel drippers<!-- 2021 --> use proprietary round disk paper filters as well (95&nbsp;mm for the LVL-10 and 77&nbsp;mm for the Pulsar). Melitta filter holders<!-- porcelain and plastics in 102 and 1×4 --> since 2018<!-- produced in China, not the older ones produced in Germany by Friesland for Melitta up to 2018, but patented much earlier: https://web.archive.org/web/20230609091014/https://www.schlossmuseum.de/sammlungen/melitta-friesland-keramik-aus-varel-rahling-1954-2007/ -->, or the Le Creuset dripper), anti-dribbling "tripod" plate design, design for simultaneous pouring into one or two cups (as for Melitta filter holders<!-- porcelain and plastics in 102 and 1×4, also Melitta Amano --> since 2018<!-- produced in China, not the older ones produced in Germany by Friesland for Melitta up to 2018 -->), double-walled design for better thermal insulation (as for Melitta Oslo Form 23<!-- 23-100 is the pot --> "102 M" filters<!-- 1964-1972 https://web.archive.org/web/20240427193955/https://www.kleinanzeigen.de/s-anzeige/melitta-oslo-kaffeekanne-kaffeefilter-vintage/2696993041-86-8070 -->, KPM Café Berlin LAB filters #2/#4<!-- designed by Thomas Wenzel, since 2015 -->, the Seltmann Weiden No Limits Barista filter #2<!-- 2013 -->, the Melitta 111th Anniversary Set filter 102<!-- MPN 6769089, 2019, similar to classical Melitta Oslo Form 23 -->, the Fellow Stagg X/XF drippers, the Chemex Funnex, the notNeutral Gino dripper<!-- (2016) -->, the Villeroy & Boch Coffee Passion V60 filter, the Brewista Tornado Duo filters<!-- at least since 2023 -->, or the Etkin 8-cup<!-- since 2022 --> and 2-cup<!-- since 2023 --> drippers), radial water feeding (like with the Ceado Hoop<!-- 2023 -->), or a collapsible design for easier storage

  • accessories like a water spreader<!-- like the Melodrip --> or cover lid or top-plate to help water distribution and reduce the temperature decline during pouring<!-- like the Clever Dripper or Goat Story GINA Smart Brewer -->, a saucer to catch coffee droplets after use, a mounting stand, <!-- a coffee measurement spoon or scale, a stirring spoon, a metal cone to press filter paper into shape (early Melitta-style) --> or coffee chilling stones<!-- like Nucleus Paragon Chilling Rocks -->.

Metal and porcelain filter holders store more heat than glass or plastic filters and therefore should be pre-heated to avoid too large temperature drops during pouring.

See also

  • Drip brew
  • Coffee pod (coffee bag)
  • Single-serve coffee container
  • Ground coffee filter ring
  • Tea bag or tea ball
  • Used coffee grounds
  • Health effects of coffee
  • Flip coffee pot
  • Indian filter coffee

Notes

[[File:Kaffeefilter.jpg|thumb|Melitta porcelain filter holder "102" with too large paper filter bag "1×4"

References

Further reading

  • The Physics of Filter Coffee — Scott Rao (xvi+249+3 pages)