Are We Capturing the Potential of Used Coffee Grounds?


I’ve chosen to explore the theme of used coffee grounds because it’s been on my mind ever since I heard an impassioned speech about coffee waste from bio-bean Founder Arthur Kay back in 2015. It was a waste I’d simply overlooked, perhaps many of us have, but Arthur saw that this waste stream held massive energy potential, and so he set about collecting it and converting it into energy.

I’d like to say that this was the catalyst for a coffee recycling revolution, but it wasn’t. Why not? Why didn’t the lightbulb ping for every café in the UK and further afield when they realised that their separated coffee grounds could be used to generate clean energy? 

Before we get there, I’d like to talk about the coffee waste issue itself. Later in this article, I will also provide some actionable tips for making use of your own waste coffee grounds.

How big is the coffee grounds issue?

The UK is one of the world’s biggest coffee-sipping nations, with an estimated 95 million cups drank per day. As a byproduct of that consumption, around 500,000 tonnes of waste coffee grounds are produced, which is not ideal.

Those coffee grounds can be a bit of a nuisance for cafés and hospitality setups who don’t know what to do with it other than to put it in the general waste bin, which, for businesses, means costly bin space. There’s also a charge for contaminated dry mixed recycling, which could make the waste management costs truly exorbitant (they’re already exacerbated by inefficient disposal measures). 

Some pragmatic coffee waste producers keep the coffee grounds separate from other waste streams and find other avenues for it, such as to use it as fertiliser. Saying that though, the vast majority of coffee waste (more than 90%) is sent to landfill where it damages the environment by emitting greenhouse gases, and where it has little opportunity to be used sustainably. 

Is there a sustainable alternative?

Anaerobic digestion plants offer the most sustainable route for coffee waste, after being used for fertiliser or on a compost heap. In an AD plant, microorganisms can break down organic material to produce energy. The only problem is that these facilities typically have a low capacity for waste. Then, there’s bio-bean, one of the UK’s most innovative waste companies, who take wet coffee grounds and turn them into circular economy-supporting bio-products such as their ‘Coffee Logs’, which generate 80% less CO2e emissions than landfill and 70% less than AD. If you ever buy coffee at Costa, you may not realise it, but they’ve been working with bio-bean for several years, helping to divert more than a third of their coffee ground waste and making significant savings in the process.

This is just one example of a well-thought-out innovation; here are some more...

What are the innovators doing?

I’m a huge fan of Berlin’s ‘Kaffeeform’, the brainchild of Product Designer Julian Lechner, who whilst studying in Italy looked deeply into the coffee grounds waste issue and decided to find a way to make the best use of this resource. After years of experimentation, trial, and error, he managed to make renewable cups that are light, machine washable, durable, and very aesthetically pleasing. They’re made of (and smell of) waste grounds!

I’m not sure I’ll ever truly understand ‘how’, but Los Angeles-based Fabric-Tech company Ettitude have managed to make comfy bed sheets from waste coffee grounds and bamboo. Their product description states: Repurposing waste with purpose. This fabric is a blend of our signature bamboo lyocell fabric and reclaimed coffee grounds. These sheets can wick away moisture and neutralise odour up to 50% faster than cotton to stay fresh for longer. The coffee grounds are spun onto a yarn using their innovative technology, changing the fibre filaments and locking in the coffee. You can learn more here.

The innovations don’t stop there. You’ll find companies making furniture, home decor, jewellery, ink, clothing, and specialist fertiliser, all from coffee waste grounds.

What can I do with my grounds?

As I mentioned earlier, I want to give you some actionable tips for dealing with your home coffee ground waste, so that you can take ideas away from this article and apply them to real life.

Use it in your garden

Coffee grounds contain some key minerals, such as nitrogen, calcium, iron, magnesium, potassium, chromium, and phosphorous, all of which are amazing for boosting the nutrient-level of soils in order to encourage growth, and for attracting insects, such as worms. The healthier the soil, the better. Just sprinkle the grounds on top of the soil and nature will do the rest.

Add it to your compost

As an add-on to the above point, you can compost your coffee grounds now and use the fertiliser later. You’ll have great results either way. It’s been found that coffee grounds make compost more nutrient-rich, as well as producing fewer greenhouse gases.

Keep away nasty critters

Fruit flies, beetles, and mosquitoes are not ideal companions when you’re trying to relax in the garden, which is an issue that you can resolve by using waste coffee grounds as a natural repellent. Simply putting a bowl on your garden table can do the trick, but even more effective is to spread some grounds around outdoor seating areas. Even slugs and snails will stay away.

For the same reason, you can also use waste coffee grounds as an additional anti-flea treatment for your pets. As fleas don’t like coffee, you might want to massage grounds into your pet’s fur after shampooing them, and then rinse again. Be careful that your pet doesn’t eat the grounds as they can prove toxic. 

Here are some of my other favourite ideas:

  • Use coffee grounds to neutralise bad smells by placing them in old socks or tights and putting them close to the source of the offending smell (think about shoes, gym bags, the fridge, or your car).

  • Use waste coffee grounds for cleaning! They make a great scrub for your hands after cooking strong-smelling foods like garlic, for cleaning pots and pans, and are also good to use to help scrub dirt from hard-to-clean surfaces. Antibacterial and antiviral in nature, this chemical-free alternative is really worth a go, just remember that coffee stains white materials!

  • Many people vouch for waste coffee grounds as a beauty product. I’ve never tried myself, but their coarse particles act as an exfoliating agent to help remove dirt and dead cells, acting similarly to microbeads (which thankfully we don’t see quite as much of these days). 

  • Use waste coffee grounds for arts and crafts projects, especially as a natural dye.

  • Perhaps the most famous shampoo that claims to make your hair grow faster is Alpecin which uses caffeine to do so. You can apply the same science by massaging coffee grounds into your scalp a couple of times per week before shampooing!

Are we truly capturing the potential of used coffee grounds?

To answer the question I set out to explore in this article, my personal opinion would be mixed, saying that yes, we are starting to and are making good progress, but also no, the figures are too low and the infrastructure is too small. There are opportunities to be had and profit to be made, I know it.

In the meantime, I continue to advise that you assess every aspect of your coffee-drinking experience, every process and ingredient, in order to improve the sustainability of your cup. If you are a capsule drinker, switch to Halo. If you use coffee grounds, do something with them. Commit to assessing your coffee consumption and its impact on the environment.