Are coffee filters biodegradable? Can they be composted?

  • Date: May 14, 2022

The Covid-19 pandemic has had an effect on many industries – the coffee industry being one of them. Widespread lockdowns meant that people could not visit their local coffee shop and, instead, opted for a home brew instead. This shift to homemade coffee has led to more coffee-related household waste. If you opt for filtered coffee rather than pods, how can you dispose of the filters? Are coffee filters biodegradable and can they be composted?

Some quick basics – what are coffee filters used for?

Coffee filters are used to trap coffee grounds whilst allowing the beautiful brown liquid to flow through into your cup. As well as the purely functional role of preventing granules in your coffee, the coffee filter will also determine how it will taste. Each different coffee filter material brings its own unique taste. Some materials let some coffee components through, whilst others don’t.

What are coffee filters made of?

As long as a material can trap solids but allow liquids to pass, it can be used as a coffee filter. They are most commonly made from paper – either bleached (to make them white) or unbleached – but there are lots of options. As people become more conscious of the waste they are producing, reusable alternatives have been sought. These mainly come in nylon mesh and stainless-steel varieties, but hemp fabric is an increasingly popular, sustainable choice.

So, are coffee filters biodegradable?

If an item is biodegradable, it means it can be broken down by micro-organisms into its component parts. Products made from natural materials can biodegrade and, essentially, return to nature. Coffee filters made natural materials such as paper, hemp and pure cotton are all biodegradable. Time taken to biodegrade will differ depending on the material. However, in optimal conditions they should all fully biodegrade in a matter of weeks to months.

Coffee filters made from nylon mesh and stainless steel are not biodegradable since these are not natural materials. Although this is not ideal, they are not single-use and, if cared for correctly, will last for many years.

Are coffee filters compostable?

Composting is becoming an increasingly popular way to dispose of household waste – and, at the same time, produce a nutrient-rich fertilizer for the garden. It will save you money and help the environment; everybody wins! It is a common misconception that the words ‘biodegradable’ and ‘compostable’ mean the same thing. However, this is not the case, they cannot be used interchangeably. Just because an item is biodegradable does not mean it is fit for the compost pile. For example, items that have chemicals added may not be suitable as they could contaminate your pile.

Coffee filters made from paper, hemp or cotton are all compostable.   As you might know – composting materials can be split into two main types. ‘Green’ materials refer to items that are rich in nitrogen such as food waste. ‘Browns’ are rich in carbon and include ingredients such as shredded paper. Coffee filters fit into the ‘brown’ category.

It is extremely important to ensure an appropriate balance of ‘green’ to ‘brown’ materials in your pile. Too much carbon can result in slow decomposition whilst too much nitrogen might cause excess heat – amongst other things. Although there are various recommendations of the best ratio, we recommend sticking to a 1:1 ratio. It is a lot simpler and minimizes the math! However, it should be noted that no two compost piles are the identical – so monitoring it is key.

If you are new to composting, have a look at some of our beginners’ tips here.    

Some considerations when composting coffee filters…

As mentioned, paper filters can be bleached or unbleached. There is debate as to whether bleached paper filters should be added to compost. Whilst some feel it would contaminate the pile, others say that the bleach will have gone before it has the chance to do so. It is your call – as always, only add things to your pile that you are comfortable with.

As when composting anything, you should cut or rip the coffee filter into small pieces before popping it in the pile. Although not strictly necessary, it will allow the bits to be spread throughout the pile and speed up the composting process. Either way, put a layer or two of other materials on top – or else you may be unpopular with your neighbor after a gust of wind…

The contents of the filter – the coffee grinds – can also be thrown into the compost pile. It should be noted that these are nitrogen-rich (a ‘green’ ingredient), so this must be considered in terms of the ratio.

The bottom line

Composting is a great way to dispose of organic waste. It is a great way to divert items form landfill and have positive impact on the environment. Thankfully for all the coffee lovers out there, natural coffee filters make a great addition to the compost pile. Paper, hemp fabric and cotton will all break down fairly quickly in the right conditions whilst adding some much-needed carbon.