Brew Quest Coffee Basics 101: Paper Filtering Your Coffee
Before you plunge into a relatively simple pour over brewing method, here is some helpful guidance on why your paper filter choice is important and how you should treat it just before brewing.
In this article, we will sidestep what we have learned thus far about extraction and learn some needed info on using paper filters and how it can affect your brew’s taste.
The reason for this side step is that nothing teaches extraction like purposely making and tasting a bad extraction, and then improving the next extraction with better technique. And, as it turns out, how you handle your paper filter requires technique that can greatly impact extraction success.
I was reminded of this yesterday when I decided to break up the monotony of my morning coffee ritual by switching to a pour over dripper I had not used in months—a simple Kalita Wave 155. If you have never seen one, it’s essentially a specially designed metal cup with a slightly funneled side and three holes in the bottom that fits nicely on top of a mug for a single serving of brewed coffee.
After going through the usual set up for this type of system, I detected an unusual smell in my coffee cup after prewetting and preheating the filter paper and dripper with hot water. A synapse fired like an old sparkplug and I was reminded why I do the prewetting/preheating step: Not only to insure I am brewing everything at just the right temp, but to also rid the filter of its papery odor that can foul an otherwise good cup of coffee.
Hence today’s topic.
Coffee Filter History
The invention of paper coffee filters and pour over brewing systems is credited to Melitta Bentz, a German woman and coffee lover who grew tired of the coffee grounds in her cup and the typical bitterness from coffee brewed in the rather messy percolator system of her day. There was also the cleaning involved in washing and scrubbing away the stains and grounds inside her coffee pot, that was a constant irritation to her coffee enjoyment.
Seeking a solution to her coffee problems, she experimented with different ways of brewing and eventually came up with an idea of brewing coffee in a pot with holes in the bottom of it to allow the brew to pass through before it could be over extracted and thereby bitter. In addition, she came up with the idea of a paper filter lining on the bottom of the pot to prevent the grounds from falling through and entering her cup.
By 1908, she received a patent for her invention and established a successful family business that eventually became famous for a number of other coffee-related inventions and improvements that continues in a company today bearing the name “Melitta” in honor of her contributions toward brewing great coffee.
Why Filter Your Coffee?
Aside from the fact that no one really likes straining coffee grounds through their teeth or feeling the fine sediments of coffee dust on their tongue, paper filters serve an important role in extraction and flavor.
In an earlier article we learned that when coffee grounds meet hot water, insoluble oils are extracted from the bean. If these insoluble oils are allowed to pass through a dripper without a paper filter, the insoluble oils become part of your beverage. If, however, a paper filter is used, much of the insoluble oils are trapped by the paper, leaving your cup of coffee with significantly less insoluble oil in it.
The difference between unfiltered and filtered coffee, is that unfiltered coffee has a fuller bodied, more robust feel and taste to it. Filtered coffee, however, is often described as producing a “cleaner cup.” In future articles, we will go more into how to interpret descriptions of coffee and flavor during cupping. But for now, it’s all a matter of taste.
Another reason why paper filters are used in brewing through a pour over system is that it helps with the extraction process, especially when pre-wetted.
The notions are that prewetting a paper filter helps form a type of seal between the paper and the dripper that not only helps keep the grounds from becoming a swirling mess when water is added, but also provides a non-airtight seal that avoids a potential vacuum effect which could significantly slow down the dripping. If you take a close look at some pour over system designs, both the dripper and the paper filters have angles, ridges and/or pleats that are designed to assist the pour over process.
That said, prewetting a paper filter also takes care of a problem that I mentioned at the beginning of this piece: it removes most of the foul papery smell that results when hot water makes contact with the paper. A type of extraction of its own, that you do not want in your coffee.
A Simple Experiment You Can Do In Your Kitchen
Most companies that sell pour over brewing systems, also specify and sell a specific paper filter to use with their system. It is a good idea to use their specified paper filters because not all filters will fit in all brewing systems, and gaps between the filters and the brewer can affect how extraction occurs.
Paper filters typically come in brown or white paper. In my experience, the brown ones have the more-papery smell and taste to them.
In any case, to experience just how much difference in taste pre-wetting a paper filter makes over not pre-wetting a filter, I would recommend that you try it for yourself with some simple sniff and tastes tests of water that has passed through your brewing device.
• You can compare water passed through a filter with water that has not.
• Try both hot and cold water.
• Pit a brown filter against a white filter.
• Try blinded sniff and taste testing with the help of a friend.
• After the water tests, see if you can taste a difference with non-wetted and pre-wetted paper filters with ground coffee brewing.
If you find that you cannot detect any difference in smell or taste between non-wetted and pre-wetted filter papers…well, there’s always beer.
Coffee talk is meant to encourage discourse between you and someone you are having coffee with, as well as for the comments section below. If you agree or disagree with the topic and what is said, or have something you would like to share, Coffee Talk is there for you.
“If she was still doing it, then she wasn’t too old to be doing it.”
—Noelle Sutherland, daughter of an “Overlooked Woman No More.”
Today’s recommended read is a NYT obituary titled “An Overlooked Woman No More,” that is part of a series of obituaries about remarkable people whose deaths, beginning in 1851, went unreported in The Times.
I chose this piece, because I found it poignant in that during a time of COVID-19 social distancing and isolation, it is a reminder that ever though we may feel like it some days, we do not have to roll over and play dead. I also chose this piece as a tribute to another remarkable woman out there on Facebook who constantly provides uplifting wildlife photos during her kayaking retirement life—a reminder that even the little things, can mean a lot to someone else.
Timothy Boyer has a Ph.D. in Molecular and Cellular Biology from the University of Arizona. For 20+ years he has been employed as a freelance health and science writer. Timothy continues writing about science with a focus on the connection between coffee and healthy living. For continual updates about the benefits of coffee on your health, you can also follow Timothy on Twitter at TimBoyerWrites.
Image thanks to photo by Nathan Dumlao on Unsplash
“Overlooked No More: Melitta Bentz, Who Invented the Coffee Filter” The New York Times.
“Overlooked No More: Audrey Sutherland, Paddler of Her Own Canoe” by Jen A. Miller, March 6, 2020 The New York Times.