What do pour-over coffee drinkers, drip-coffee drinkers, and AeroPress coffee drinkers all have in common (other than a love for coffee)? They all use coffee filters to make their morning joe. Chances are, if you’re here, you do too. Few things are better than a morning cup of coffee, and it’s about to get even more exciting because we’re here to tell you that, yes, you can compost your coffee filters. 

Composting coffee filters keeps a daily-used item out of the landfill, instead sending it onto a better second life. Before you get started, there are a few specifics you should know about adding coffee filters to your compost bin or pile. Here are the hot tips for handling used coffee filters. 

Can you compost coffee filters?

A healthy backyard compost pile is made up of both green compost materials (nitrogen-rich) and brown compost materials (carbon-rich). For best results, you should always aim to have about two to three parts brown materials to one part green materials. Coffee filters alone, without coffee grounds in them, are considered a brown material, just like cardboard, dry leaves, or straw. Coffee grounds are considered a green, like other food scraps. 

You can scrape out used filters to layer your greens and browns separately or keep them together — just be sure to keep track of the green-to-brown ratio of your compost pile. Because the ratio of grounds to filter is so much greater, a coffee filter with grounds in it is much more of a nitrogen-rich green than it is a carbon-rich brown. 

Regardless of whether you’re using unused filters or filters with grounds in them, just make sure that the filters you’re using are the kind that can be composted. 

How to identify compostable coffee filters 

Unfortunately, not all coffee filters are compostable — and there’s rarely a warning label telling you when they aren’t. Here’s what to look for.

They don’t have synthetic materials

Some coffee filters, especially the more durable or "premium" options, may be reinforced with synthetic fibers like plastic that act as a bonding agent. Although they may improve the strength and durability of your coffee filters, those synthetic materials won’t break down in the compost pile. Over time, they can also contaminate your compost with non-degradable microplastics. So, if you’re hoping to compost your filters, make sure to purchase ones that say “compostable” on the packaging. 

They’re bleach-free

Another important factor in identifying compostable coffee filters is whether or not they’re bleach-free. Some paper filters are treated with chlorine bleach, and bleached coffee filters can’t be composted. If composted, chlorine-bleached paper can release harmful chemicals into the compost as it breaks down. This can damage the quality of your compost and also harm your plants. Look for unbleached coffee filters, which are typically brown in color and also usually marked as “compostable” on the packaging. 

How to compost coffee filters

If you thought you could just throw whole coffee filters into your compost pile, well, you’re not totally wrong — but you’re not totally right, either. There are a couple of things you can do before adding coffee filters to compost to make the decomposition process simple.

At home

As with pretty much anything you’d plan on adding to a compost pile, it’s best to break up coffee filters into smaller pieces first, using your hands or a pair of scissors, just shred the coffee filters into tiny pieces. This will speed up the composting process and allow the filters to break down more easily.

If you’d prefer not to get your hands dirty, you can also pre-process coffee filters in a Mill. The Mill food recycler will dry out and grind the coffee filter (and coffee grounds) for you, that way you can keep the coffee in your mug and the grounds out from underneath your nails. 

Just remember that used coffee filters can only be added to Mill if you plan to use your Food Grounds in your backyard or add them to a city composting program. You should not put coffee filters in Mill if you send the Food Grounds back to Mill or plan to feed them to your backyard chickens — even though coffee filters are compostable, they are not a suitable ingredient in chicken feed. 

City-run composting

If you don’t do home composting, or you’d just rather not worry about tearing up used filters, you can compost coffee filters through your municipal composting program — if it’s allowed. While most major cities, like New York City, accept them, some may not. Denver, for example, doesn’t allow paper coffee filters to be composted, so make sure you check. 

Alternatives to composting coffee filters

If you’d rather skip the whole composting coffee filters thing altogether, there are still several ways to be environmentally friendly and prevent single-use items from being sent to the landfill (and none of them involve stopping drinking coffee, thank goodness). 

First, you can invest in a French press — a coffee preparation mechanism that involves no filters whatsoever. All you need are coffee grounds, a French press, hot water, and time. If that’s not necessarily your thing, you can also start to reuse coffee filters. Some disposable coffee filters, especially those that come with a plastic lining, are actually meant to be reused. Although the plastic prevents them from being compostable, being able to reuse them is the next best thing. 

Finally, you can invest in one of the many metal or mesh reusable coffee filters. These filters are designed to be used over and over again, with no added plastic and nothing left over to send to the landfill — simply dump the grounds into your bin, rise, and it’s ready to use again. Really, it’s a win-win situation. 

Whether you go the reusable route or stick to paper filters, coffee grounds, and paper filters can always be added to your Mill. The Mill will turn your food waste and byproducts, like coffee filters, into food grounds that can be used as a soil amendment or added to your compost pile. That way, even your plants benefit from a little pick-me-up from your morning cup of coffee. 

Sources:

1. U.S. Department of Agriculture: “Composting.” https://www.usda.gov/peoples-garden/food-access-food-waste/composting

2. City and County of Denver: “How to Compost.” https://denvergov.org/Government/Agencies-Departments-Offices/Agencies-Departments-Offices-Directory/Recycle-Compost-Trash/Compost/How-to-Compost