Can You Compost Coffee Grounds & Coffee Filters?

can you compost coffee grounds and coffee filters

Surely ground coffee has to be up there with one of nature’s greatest gifts?

Although the first coffee house opened in the UK in the 1600s, the coffee plant has been utilised by people since the 9th century. It’s not clear exactly when or where coffee first originated, but legend has it that an Ethiopian farmer noticed animals becoming energised after eating the coffee berries, leading him to give it a go for himself!

A good few hundred years on and coffee is one of the main powerhouses of the world, fuelling a combination of work, enjoyment and moments of relaxation.

As the world has become more conscious and environmentally aware about what to do with waste, people want to know what to do with the copious amounts of coffee grounds and filters they are going through.

If you’re anything like me, I probably brew and drink 3-5 ground coffees a day. But what should you do with all the left-over coffee grounds? Are they compostable? Can you put coffee filters in the compost pile too? Let’s find out.

Can you compost coffee grounds?

Coffee grounds are 100% plant based coming from either the Arabica or Robusta coffee plant. This means that they will breakdown into its constituent organic parts over time no problem.

Yes, you can compost coffee grounds.

Even though roasted coffee beans are brown, they are classed a ‘green’ compost waste for their higher nitrogen concentration. Brown compost waste, such as paper coffee filters discussed here and twigs, are carbon rich.

In total, it’s suggested that no more than 20% of the total compost volume should be made up of coffee grounds. A good compost pile needs a fine balance of different types of organic waste and minerals. Too much of one material will cause an unwanted tip in the balance.

You can even get compostable coffee packaging now such as Omnidegradable and 100% plant based coffee packaging. On this topic, foil-lined coffee bags are still not recyclable. Have a read of this blog on if you can recycle coffee bags.

From what I’ve read I’d stay away from adding coffee grounds directly onto the surface of soil as a mulch. Although it’s quite popular for blogs and other websites to say add coffee grounds to soil, there isn’t much evidence to suggest it helps. In fact, anecdotal evidence suggests applying coffee grounds to the surface of soil doesn’t help plants at all.

The reason coffee grounds don’t make a good mulch material is that it is caffeinated. Caffeine is used by the likes of coffee plants and tea plants are a ‘poison’ to the soil to inhibit other plant growth, reduce germination and competition!

Before we get onto the compostable matters of coffee filters, let’s just have a quick look at the background of these filters to give you a better understanding.

omnidegradable coffee packaging tekpak solutions django coffee
A lovely ground coffee and Omnidegradable packaging which is also compostable

Are coffee filters bad for the environment?

For this blog when talking about coffee filters, I’ll be discussing the paper coffee filters. There are other types of filters out there but paper is the most common type of coffee filter.

Coffee filters papers generally come in two camps: unbleached or bleached.

Like all paper, coffee filter papers come from a tree, which naturally give the paper a brown colour. Unbleached coffee filters still hold this brown colour. Bleached coffee filters however have been treated so they appear whiter.

Bleached coffee filters have usually been treated with a chemical agent such as chlorine to change their colour. Treating with chlorine can cause environmental issues when the filter starts to decompose in nature. A study in 2012 found that chlorine-bleached coffee filters can cause environmental issues in pulp and paper mills, so I think it’s fair to say that this can be a problem in nature too.

There are other types of bleaching however that are more environmentally friendly, such as oxygen bleaching.

So, the difference between bleached and unbleached coffee filters is purely aesthetic. There is no other benefit.

Some people may say they affect the taste of the brewed coffee differently. Neither bleached nor unbleached coffee filters should impact the flavour of the drink too much if at all. This may depend on the quality of the paper and if you have a professional coffee taster palate or not.

I have used both types of filters in the past and have never noticed a difference. With either type of coffee filter, make sure you rinse the paper before use to try and get rid of the chance off-flavours being filtered through with the coffee.

As with most products and resources, all coffee filters require a certain amount of manufacturing and will therefore have some form of associated carbon footprint. Composting your coffee and coffee filter papers will help reduce the environmental impact by eventually putting the useful minerals back into the soil.  

Unbleached or bleached: which coffee filters are compostable?

Ok, so we know the actual used coffee grounds are compostable but what about the filter papers.

If your coffee filters have been bleached with a chemical agent such as chlorine, they are no longer fully organic. Even though only a tiny amount of chlorine is used in bleached filters, you may not want to include this in your natural compost pile.

Depending on how many filters you go through, depends on how much chlorine could make its way into your compost. As chlorine-bleached coffee filters can have negative environmental issues, I wouldn’t necessarily want to contaminate my decomposing organic mass. That said, chlorine is a natural element and will break down, meaning you may still be able to compost small amounts of bleached coffee filters papers.

I don’t want to bash chlorine as it does an important job, including making our drinking water safe to drink, and is therefore is safe to use in coffee filter papers but I think it is unnecessary for use in filter papers.

An unbleached coffee filter is slightly less manufactured and doesn’t have any other chemicals added. This means that unbleached coffee filters are better for the environment and compostable.

When buying your coffee filters look out for the common compostable logos and also the TCF (totally chlorine-free) mark.

Even better make sure your filters are sourced from a 100% FSC (Forest Stewardship Council) certified paper source. This let’s you know that the trees grown to provide the paper are grown in a sustainable manner.

Can you put coffee filters in the food waste?

This may depend on your local authority and the rules of whoever is picking up your curbside food waste.

On the whole, yes you can put coffee filters in with your food waste. As we’ve seen, these paper filters are compostable and will breakdown organically.

For me, I use unbleached, compostable coffee filter papers that I put straight into my food waste bin to be collected by the council.  

used coffee grounds from moka stove top
Used coffee grounds and my stove top filter. These will be composted in my food waste bin.

How long do coffee filters take to decompose?

Managing a compost pile can be a precarious undertaking.

Certain conditions need to be created to ensure decomposing is occurring at a decent level. All compost piles require a good balance of green and brown organic waste, as well as moisture, oxygen and heat.

Adding too many coffee grounds and coffee filters could upset the balance and the organisms that are doing the hard work. This will significantly slow down the rate of decomposition.

On the whole you’re looking at 6-8 months for your coffee filter to decompose.

If your coffee filter is added whole to your compost pile, it may take longer to decompose. A good tip is to try and shred the paper up as much as possible to speed up the process and mix it into the pile when added – don’t just plonk it on the top!

Are permanent coffee filters better than paper?

If you’re considering a filter from an eco-friendly living perspective, then yes permanent coffee filters are better. For taste reasons, this all comes down to personal preference.

Permanent coffee filters, such as steel versions, will filter the coffee differently and potentially not as finely as filter papers would. But because they are fully reusable over time, you’ll be saving a lot of filter paper resource use. Reusing something is always better for the environment than a single use item.

My preferred ‘permanent’ filter is that in a cafetiere. All you need here is the ground coffee which can definitely be composted afterwards. My ground coffee of choice at the minute is this organic Cafedirect Machu Picchu single origin. The cafetiere filter can then be cleaned and washed out with a bit of soap and water ready for the next use.

A stove top moka also contains a fully reusable permanent filter. Here the water comes to the boil and the pressure forces the water up through the steel filter to the where the ground coffee is and then up through the spout and into the top chamber. Once cooled, clean with soap and water and it’s ready for the next brew.

The coffee filter wrap up

In short, yes both coffee grounds and paper coffee filters are compostable.

Coffee grounds are completely natural and are ultimately like any other plant when it comes to composting.

Paper coffee filters have to be manufactured but they are paper and come from trees. The question of bleached vs unbleached shouldn’t make too much difference to whether it’s compostable or not. Some coffee filters will contain the OK compost logo, or some other accreditation, meaning that no other additive or non-compostable material, such as plastic, has been used to make the filter paper.

Unbleached coffee filters are generally better for the environment and work exactly the same as bleached ones. The only difference here is a case of aesthetics. Why would you want a white filter anyway? This to me is unnecessary.

Brown, unbleached coffee filters are less manufactured, more natural and compostable, which make them a much better choice in my eyes. You can buy your very well priced FSC certified compostable and unbleached filter papers from andkeep.com.

Disclaimer: This post does contain a couple of affiliate links. I only recommend products if I 100% believe in them and have used them myself. Using these links will not change the price in any way but I may earn a commission as a small thank you from the seller.


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*Thanks to Tyler Nix on Unsplash for the header image.