Coffee News: from Seed to Cup

The Great Paper Coffee Filters Debate: Bleached vs Unbleached

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Coffee filters: they’re small, humble, and critical for great-tasting coffee. But if you – like the majority of coffee brewers – use paper filters, should you purchase bleached or unbleached ones? What can you do to avoid a papery taste in your coffee? And is there anything else you should be looking out for? Read on to find out.

Spanish Version: El Gran Debate de los Filtros de Café: Decolorados Vs Sin Decolorar

kalita waveCoffee brewed on a Kalita Wave using a bleached filter. Credit: The Cappuccino Traveler

The Origin of Paper Filters

While the cloth filter (the “sock”) has been around for a long time, the paper filter didn’t appear until the turn of the twentieth century. Melitta Bentz, a housewife and avid coffee drinker in Dresden, East Germany, was tired of finding grounds in her coffee. She knew there had to be a better and easier way to filter her brew.

After experimenting with different materials and methods, she eventually decided to try her son’s blotting paper. She cut out a piece, put it in a metal cup, added the grounds and proceeded to pour water over it. Realizing there weren’t as many grounds in her coffee, she then applied for a patent.

And so on July 8, 1908, the paper coffee filter was patented as a “Filter Top Device lined with Filter Paper.” That same December, Mrs. Bentz founded the Melitta Bentz Company, and the rest is history.

Today, coffee lovers drink a wide range of pour over methods, all of which require a filter. And while some people use use a coffee sock or a gold filter, most of us opt for bleached or unbleached paper ones.

But which is better?

chemexCoffee brewed on a Chemex with an unbleached filter. Credit: Josh Burke

Bleached Coffee Filters: The Basics

The main difference between bleached and unbleached coffee filters is that bleached ones have been whitened. This can be done through a tiny amount of chlorine or something called oxygen-bleaching.

Although there was concern in the ‘80s that chlorine-bleached filters might be dangerous, it’s now widely accepted that they’re safe to use for brewing coffee. What’s more, the bleaching process won’t add any flavors to your drink.

However, there are still concerns over their environmental impact. In fact, a 2012 study published in Environmental Engineering and Management Journal found that discharge from chlorine-bleaching was “the most significant environmental issues” in pulp and paper mills. In contrast, oxygen-bleaching requires less manufacturing and is better for the environment. All major filter brands make clear which bleaching method they use on their packaging.

coffee filterBleached paper coffee filters ready for use.

Unbleached Coffee Filters: The Basics

Unbleached filters don’t have that bright white color like their bleached equivalents do, but they are slightly better for the environment. This is because they don’t require as much processing.

Most of the everyday paper you see and use is bleached. Paper is naturally brown (it does, after all, come from trees). Yet unfortunately, if you use an unbleached filter in your pour over or coffee machine without rinsing, there’s a chance that you might taste papery notes.

That being said, you may also get papery notes from bleached coffee filters, depending on the quality. No matter the brand or manufacturing methods, it’s always a good idea to rinse paper filters before use.

filter coffeeCoffee brewed with an unbleached paper filter.

SEE ALSO: Brew Guide: What Are The 3 Phases of Filter Coffee Brewing?

How to Remove That Papery Taste

Rinsing paper filters will help avoid that unpleasant papery taste in your coffee, and at the same time preheat your brewing device. Here’s how to do it:

  1. Place your filter in the brewing device
  2. Pre-wet the filter by pouring hot water over it (make sure not to leave gaps!)
  3. Discard the water
  4. If necessary, rinse a second time
  5. Continue to brew your coffee

Most filter papers should be good to use after one rinse, but some may require a second one (especially if you have a sensitive palate). And if you’re still getting a papery taste after a second rinse? Change your filter brand.

coffee filterFilter being rinsed with hot water, ready for brewing. Credit: Michael Flores

Filter Quality & Thickness

Although we’ve been comparing bleached and unbleached paper filters, you should remember that this isn’t the only difference. The quality of your filter is also important for ensuring clean coffee profiles and good brew flow. Even the slightest difference here can have a big impact on your drink.

On top of that, make sure to choose the right size filter for your brewing method, and pay attention to thickness. Filters that are too thin will allow water to flow through too quickly, and thicker filters may keep more oils out of your brew. If you’re looking to buy a thicker filter, prepare to pay a little more. Luckily, the difference in price is minuscule.  

filter coffeeChemex coffee brewed with a bleached paper filter. Credit: Karl Fredrickson

So… Which Is Better?

In the great bleached vs unbleached paper coffee filter debate, it really comes down to your preferences: taste or environmental impact.

If you want to be more eco-friendly, buy high-quality unbleached filters and rinse well before use. On the other hand, if you’re concerned that your coffee might end up with a papery taste, even with double rinsing, opt for bleached – ideally oxygen-bleached – filters.

Oh, and remember that quality matters! A cheap bleached filter may add just as much of a papery taste to your coffee, if not more, as a high-quality unbleached filter.

Written by Brendan Nemeth.

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