Coffee Filter Pore Size

This article is focused on the coffee filter pore size and reveals the common size for paper filters and standard that is used by manufacturers of drip coffee makers.

You can, if you so wish, but smaller pore size filter for pour over coffee which results in a stronger and bolder cup of coffee.

Keep reading to find out the pore size of coffee filters.

Coffee Filter Pore Size – How Many Microns?

Unfortunately there is no set standard for coffee filters in terms of the pore size, the majority of paper coffee filter, regardless of their size or shape, is 20 microns.

Metal and cloth coffee filter have their holes designed to be this same size to match the flow rate of paper filters.

Even thought there would be a demand for pore sizes to be slightly smaller for those that want to brew a cup of coffee that is slightly stronger due to smaller size resulting in a slower flow of water from the filter and into your cup. This results in a slightly longer contact time between the hot water and the coffee grounds.

The problem with this is a consistent pore size is needed for the manufacturers of drip coffee makers. If you use a smaller pore size than what your coffee maker is designed for, you will flood your coffee basket and have a horrible mess to clean up.

You may even short circuit and break your coffee maker.

Even though there is no standard size set for paper filters the manufactures assume and work with an assumed consistent pore size of 20 microns.

This filtration size will filter out all the coffee particles an grounds preventing them from entering your cup of coffee and allowing water to pass through.

Read: What to use for coffee filter

Metal Coffee Filter Micron Size

A metal coffee filter micron size is slightly larger than a paper filter but there are fewer than a paper filter.

Metal and cloth filter are engineered to have a true pore size per centimeter squared as a paper filter to allow for the flow rate to be the same and thus the contact time that the hot water has with the coffee grounds.

10 Micron Coffee Filter

Super fine mesh10 micron coffee filters exist and are a great choice for pour over coffee but not for drip coffee machines.

The 10 micron coffee filter size will result in a notably slower flow rate and a longer brewing time due to the increased contact time that your hot water has with the coffee grounds.

The true pore size of this filter is half that of regular paper filter. It’s a great choice is you love a stronger and bolder tasting pour over coffee.

Frequently Asked Questions About Coffee Filter Pore Size

How Many Microns Is A Typical Coffee Filter?

The majority of coffee filters are 20 microns, although there is no standard or set size to use and thus they vary slightly. Both cloth and metal filters have slightly larger pores which allow more coffee particles to pass through them.

What’s The Difference Between #2 And #4 Coffee Filters?

The difference between a #2 and #4 filter is their size. A #2 coffee filter is designed to brew 2 to 6 cups of coffee and are adapted specifically for a coffee maker that brews this number of cups of coffee. A #4 coffee filter size is designed to be used with a drip coffee maker that has the capacity to brew 8 to 10 cups of coffee.

What Is Size 4 Coffee Filter?

A #4 filter is the size to use if you have a coffee maker that can make 8 to 10 cups of coffee or larger pour over coffees. If you plan on making up to 10 cups of pour over coffee, this is the size that you should use.

Does It Matter What Size Coffee Filter You Use?

Yes, you must use the correct size of coffee filter for your machine. If you use a #4 filter in a machine that is only designed to brew 2 to 6 cups of coffee, you will end up saturating your machine and end up with a big mess to clean up.

Why Are Brown Coffee Filters Better Than White?

Brown coffee filters are better than white filters as they are unbleached filters. Paper is brown naturally and only turns white after a bleaching process. Due to being unbleached and less processed, they are much better both for your coffee and the environment. 

Read: Coffee filter sizes

Which Coffee Filters Are Healthiest?

The best paper coffee filters are high quality unbleached fliters simply due to being chemical free. I still advise rinsing them before use. The best of the best and the healthiest?

From my point of view, metal coffee filters are a better choice as you get a fuller flavor and more coffee oils into your cup of coffee, many of which have health benefits. However, if you have high cholesterol, stick with unbleached paper filters.

Final Thoughts – Coffee Filter Pore Size

The common coffee filter pore size is 20 microns which is perfectly fine for regular pour over coffee and automatic drip coffee makers.

However, if you like to coax out more flavors from your coffee ground while using the pour over technique you can find coffee filters that are half that size, 10 microns.

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Derek Marshall

Derek Marshall, a certified barista by the Specialty Coffee Association possesses over two decades of experience in specialty coffee shops. He holds professional certifications for coffee brewing and barista skills. Derek is also an author with authoritative books covering various coffee topics including specialty coffee, sustainability and coffee, coffee brewing, coffee recipes, coffee cocktails and books focusing on Brazilian coffee, Vietnamese coffee, Indonesian coffee and Malaysian coffee. As a barista for over two decades, Derek Marshall has worked in specialty coffee shops across the United Kingdom, Spain, Thailand, Malaysia, Cambodia, Indonesia, and Vietnam. His expertise extends to the distinct coffee cultures, specialty beverages, and brewing techniques of each nation. Functioning as a coffee consultant, Derek charges US$50 per hour. To learn more about Derek Marshall and Latte Love Brew, visit his About Me Page. For coffee inquiries, contact him at +34-639-410-375 or Derek@LatteLoveBrew.com, mentioning your name and location