Can you put coffee filters in a compost bin?

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Can you put coffee filters in a compost bin?

Using paper coffee filters appears to be the best way to filter fresh made coffee. With paper the filtration is complete, compared to using metal mesh filters which do a good job but tend to allow, some, very fine solid particles through. All paper filters have to be disposed of and that includes coffee filters.

So, can you put coffee filters in a compost bin? Are coffee filters compostable?

You can safely put coffee filters in with the rest of the compost. All paper is biodegradable. Paper is carbon based and once living, so that makes it organic in the true sense of the word. If you are doing any composting, of any type, that takes regular amounts of kitchen waste, then, you can put in all the coffee filters that your coffee-drinking habits generate. 

Are coffee filters compostable?

You can do so and forget that they are coffee filters. You can ignore the fact that they’ve had anything to do with coffee. There’s nothing about a coffee filter that will impede or worry any aspect of your compost making. This is paper. It comes under ‘browns’ on that short table of comparisons of ‘greens and browns’.

You can also ignore all comments that may worry you into thinking that coffee filters pose some sort of hazard because they’ve been bleached. There will be no residues left on the paper as a result of the bleaching process. 

The chlorine that was used to bleach your coffee filter will be long gone before you use it as a filter. If there is any chlorinated residue on a paper filter, people would smell it and taste it in their coffee and then there would be complaints.

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So, in a used coffee filter we have a once-clean piece of paper which we’ve used to filter solids from a liquid which happens to be coffee. It can go into the compost bin, where it will become moist from the rotting ingredients around it. It will then be inspected by worms. When it’s degenerated to an agreeable state that attracts the worms, they will ingest it, digest  it completely and the coffee filter will be converted to worm casts.

 How long do coffee filters take to decompose?

Think of coffee filters as being the same as newspaper. There is nothing special about coffee filters. They will break down along with everything else. If you have a static bin, then, this will take longer than if you’re feeding a compost tumbler. 

Can you put coffee filters in a compost bin? Yes. It’s paper – carbon ‘brown’.

When coffee filters, newspaper or any other paper products are fed to the Rolypig composter, they break down very quickly. This is partly due to the occasional rolling of the Rolypig but mainly due to the massive population of worms that have built up. They will go for any soggy paper before they go for anything else. While we see the occasional teabag that has survived the journey through the Rolypig; teabags are, in part, plastic, we never see any other paper items including coffee filters. 

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Are coffee filters bad for the environment?

There’s nothing about paper coffee filters that’s bad for the environment. Nor is there anything bad about any of the processes that  are used to make paper coffee filters. 

There are two types of paper coffee filter. There’s non bleached and bleached. The non bleached filters tend to carry the original colour of the paper that come straight from the pressed or rolled paper pulp. The advice when using non bleached paper filters is to rinse them with boiling water before using as a filter for the hot coffee. This is to remove the taste of paper that may occur when using non bleached filters.

You may feel inclined to rinse bleached filters for the same reason but there shouldn’t be any taste of paper. The chlorine that’s used in the bleaching process will have removed all traces of taste of paper and colour. This is done, purely, for aesthetic reasons. There is no need to rinse bleached filters because of the involvement of chlorine in the bleaching process. 

All traces of chlorine will have departed soon after the moment when bleaching occurred. Chlorine is a safe chemical and, when managed correctly, poses no risk to the environment.

Which coffee filter should we be using?

Paper coffee filters will make a cleaner cup of coffee because paper will provide a much more fine filter. It will filter out the finest of particles so that you don’t see anything in the bottom of the cup. If you aren’t too bothered about the sediment then, a stainless steel filter is the way to go. It will be one expense rather than having to keep buying fresh filters but it will involve cleaning after every use.

Given that both the paper coffee filters and the grounds can all be composted, no one should feel inhibited about making coffee using paper filters. There is a choice of paper filters. If you aren’t happy about using filters that have been bleached, there are non bleached coffee filters available.

Is it OK to use paper towels as coffee filters?

By all accounts it’s easy to filter coffee using a paper towel. Paper towels aren’t made for the job, so you have to do a bit of an ‘origami’ to make it work. This is ideal if you have run out of the official filters that are made for the purpose. If you are satisfied with the performance that a paper towel gives you, there’s no reason why you can’t make this a regular habit.

If filtering your coffee is important to you, there are other less sophisticated ways of doing it. Looking around, we’ve found a few interesting suggestions. Someone suggested using a clean sock, yes, the sort that you wear on your foot.

You could get a stainless steel fine filter but these won’t filter as effectively as a paper. Then there are those who take a chance and put the coffee in a kettle, bring to the boil. Allow a moment to let it settle before pouring and the grounds will stay as a layer in the bottom of the pot.

Finally, it may be heresy to suggest it but there’s always instant coffee.

Can you put too many coffee grounds in compost?

Waste ingredients that fall into the ‘greens’ or ‘browns’ can be overdone. That’s why you need to know which category you have in your hand. Coffee grounds fall into the ‘greens’ category. So, if you have a large amount of coffee grounds which you have collected from one of the coffee cafes, you need to know how to make best use of it.

Feed it into the compost by adding a little at a time as you feed other kitchen or garden waste. Coffee grounds may start to deteriorate before you’ve finished adding it all to the compost but how can that be a problem, you want it all to rot down in the end.

Coffee grounds are slightly acidic. It takes extra management when you add anything that’s acidic to compost. Acidity preserves. You often know when a compost heap is acidic because there’s usually a smell and an excess of flies in the area.

There is a simple way of preventing this. You need to add hydrated white lime. Every composting system will benefit from hydrated white lime. It will react with the acids that are generated when compost is forming. When organic material breaks down or rots, the mass becomes acidic, it’s a natural consequence of decomposition.

Acidity preserves, think pickled onions. Kitchen and garden waste will turn into compost quicker and more efficiently if the composting mass is non acidic. The adding of a sprinkle of hydrated white lime every time you feed the heap will bring the mass as a whole to a neutral ph level. These will be the best conditions that you can create for making compost from anything that’s compostable.

It would be possible to mix hydrated white lime to a heap that consists of nothing but coffee grounds. The acidity would be reduced to zero. It may be necessary to mix in some shredded paper or chopped dead leaves as a carbon ‘brown’ addition to balance the mix. This could  be a highly productive way of making use of a large acquisition of coffee grounds from a coffee cafe.

Related questions

Which plants do not like coffee grounds?

If you have an abundance of coffee grounds, from whatever source, you may be tempted to use them as a mulch. Because there is an acidic factor here, it would be wise to only apply it to plants that prefer acid soils. Apply a thin layer of coffee grounds on the soil surface because a thick layer may dry out and form a hard cap that stops water from getting through. You can avoid this by digging it into the ground. 

Do coffee grounds repel slugs?

It’s possible that coffee grounds will repel slugs but it will only be for a short while. Whatever there is in coffee grounds that slugs may not like, it will be either washed out or erode away after a short while. It takes a lot to keep out a slug.

Is coffee grounds good for grass?

A thin broadcasting of coffee grounds on grass is a good way of making use of the range of nutrients that it can provide. Remember that there is an acidic element with coffee grounds. This can be managed on grass by applying, our old favourite, hydrated white lime. This will neutralize the acidity, something that the lawn may benefit from regardless of whether coffee grounds have been spread or not.

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What else would you like to know?

Can all food waste be composted?

Can I put cooked potatoes in the compost?

Can you grow your own mushrooms?

Can you put carrots in compost?

How moist should a compost pile be?

How often do you turn your compost pile?

 Is it better to leave grass clippings on the lawn? How do you speed up composting. What not to put in your compost pile 

How long does it take to make compost? What can you put in your compost bin? What is a compost accelerator? 

Can you put grass clippings in compost? Can I put urine in my compost bin? Smelly Compost 

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Coffee filter


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