Bleached Vs Unbleached Filters – What’s The Difference?
There are two common types of paper filters available in the market: bleached vs unbleached.
The most obvious difference between them is the colour: unbleached filters are brown, while bleached ones are white, as would be expected.
But have you ever wondered if there are differences other than just colour? Which is better from an environmental perspective? Does bleaching affect the taste of coffee?
Bear with me and you’ll find out!
How Are Paper Coffee Filters Made?
Today, most coffee filters are made from paper. Trees are processed into pulp, which is then refined to create coffee filters. This whole process happens in large-scale paper mills that spew out hundreds of tons of pulp and paper a year.
You can watch this video for a closer look at how tree trunks are turned into coffee filters:
During the production process, some coffee filters are bleached, while others are not.
Why Is Paper Bleached?
Paper is bleached for purely cosmetic reasons. While brown paper might look less pristine, it’s just as hygienic as white.
When paper is recycled, it goes through a lengthy process of cleaning, testing and quality control to ensure it is safe for use.
Of course, wood pulp is also naturally brown, even at first use. So when it comes to paper, brown doesn’t necessarily mean “recycled”, and “recycled” definitely doesn’t mean “dirty”.
How Are Coffee Filters Bleached?
Paper mills use several different bleaching methods. In the past, chlorine chemicals were often used to bleach wood pulp. However, chlorine bleaching has detrimental effects on the environment, increasing air pollution and toxic waste water.
After pulp manufacturing, chlorine bleaching is the second biggest polluter in the paper industry. If paper mills stopped bleaching with chlorine, air pollution and toxic waste water would be significantly reduced.
However, it’s good to know that paper mills are adopting alternative bleaching methods which don’t burden the environment as much. Chemicals like hydrogen peroxide and oxygen are now being used to replace chlorine chemicals.
Especially in the big pulp-producing countries of Scandinavia, chlorine bleaching has been replaced with more environmentally-friendly methods like oxygen bleaching.
Companies like Hario now explicitly state it if their filters are oxygen-bleached, making it easier for consumers to choose.
If you want to buy bleached coffee filters, go for ones marked “TCF”, which means the paper has been bleached 100% without chlorine.
Impact On Taste Is Small
When comparing the taste of coffee that is brewed with bleached and unbleached filters, the difference is minimal.
Unbleached filters may impart a slight paper taste, but this can be avoided by carefully wetting the filter before brewing coffee. This is standard practice for pour-overs anyway.
The paper taste may, however, vary between filters of different quality, so it’s good to do some research before you buy.
This taste test by Prima Coffee found a noticeable paper flavour in unbleached Chemex filters, but practically no difference between bleached and unbleached V60 filters:
But if you want to make 100% sure you are getting a clean flavour, oxygen-bleached filters are a safe choice. Just read the label!
To Bleach Or Not To Bleach - That Is The Question
Bleached and unbleached filters are differentiated by their colour, which in turn is derived from how they are manufactured.
For a more environmentally conscious choice, you should go for bleached filters which have a TCF chlorine-free label.
Ultimately, it’s your own choice. Some people say unbleached filters impart a paper taste to the coffee, while others notice no difference.
Have you tried comparing coffee made with bleached and unbleached filters? Did you notice a difference? Let me know in the comments!