What does a coffee filter do? Paper vs metal vs cloth filters

What are the main types of coffee filter?

There are three common families: paper, metal mesh and cloth. Wikipedia also lists nylon, porcelain, ceramic and plastic options.

Wikipedia lists cloth filters made of cotton, hemp, linen or flannel. How much oil and sediment they let through is less documented, so that column says varies.

Do paper filters change the taste?

Yes, in two ways. They hold back oils, which makes the cup lighter and cleaner. Wikipedia also reports that paper-filtered coffee tastes "somewhat fruitier" than coffee from permanent filters.

Paper can add a taste of its own. Some baristas notice a "paperish" flavor, according to Wikipedia, and recommend rinsing the filter first. Counter Culture suggests a simple test: pour hot water through a dry filter and taste it. If it tastes papery, rinse before brewing.

Are paper filters better for cholesterol?

The evidence says paper-filtered coffee is the safer choice for heavy coffee drinkers. A 2025 Uppsala University study found that a regular paper-filter drip machine "manages to almost completely filter out" cholesterol-raising diterpenes.

The study also tested French press, percolator, espresso and boiled coffee. Boiled coffee had the highest levels per cup. Its authors concluded that for people who drink a lot of coffee daily, drip-filter or other well-filtered coffee is preferable.

This is a health note, not a reason to avoid French press entirely. It matters most if you drink several cups a day, every day.

Why does a metal filter need a coarser grind?

Because fine particles slip through the mesh. Perfect Daily Grind warns that a French press's metal filter lets fines through, leaving too much grit if the grind is too fine. It recommends grinding "quite coarse, think granules rather than sand."

Paper is much tighter. Wikipedia describes typical filter paper with filaments about 20 micrometers wide. That is why a pour-over can use a medium grind without much sediment.

This is where the grinder matters. A grinder that makes many fines at coarse settings will leave more sludge in a metal-filtered cup. The grinder finder matches grinders to the way you brew.

Who invented the paper coffee filter?

Melitta Bentz, in Germany, in 1908. Wikipedia dates her invention to July 8, 1908, and says she wanted to remove the bitter taste caused by overbrewing.

Her first design was a 94 mm round paper disk. She patented it and founded the Melitta company. Paper filters are now common in drip coffee machines.

Today paper filters come bleached or unbleached. Wikipedia describes the typical paper as about 100 grams per square meter.

What do filter sizes like #2 and #4 mean?

They are standard sizes for cone and basket filters, mostly in the US. Wikipedia lists #0, #1, #2, #4 and #6, with #2, #4 and #6 the most popular.

The number tells you which brewer the filter fits, not how fine it filters. Check your brewer's manual and buy the size it names. For brewer-specific guidance, see our Chemex vs V60 comparison or the French press brewing guide.