The world generates 560,000 tons of spent coffee grounds each day. Source: Unsplash
Humanity’s daily consumption of over two billion cups of coffee comes at a cost to our planet, since coffee preparation leaves behind some 560,000 tons of grounds every day. Each ton of discarded grounds can emit as much as 340 cubic meters of methane as it decomposes, charging the atmosphere with a gas that has 86 times the climate-heating impact of the same volume of carbon dioxide.
Fortunately, both companies and consumers are devising ways to reuse, recycle, or repurpose coffee grounds to reduce environmental impact. One example is a Latvian start-up called KoffeeCo., which converts used coffee grounds into oil that can be reused in the biopolymer and cosmetics industries. They also turn spent coffee into “logs” that can be burned for heating or cooking and that comply with the European Union’s emissions regulations. The coffee logs are more efficient in heating and they burn cleaner, creating less greenhouse gas, the company says. KoffeeCo also crafts disposable tableware. The company has received €70,000 in funding from the Investment and Development Agency of Latvia (LIAA) and now looks to raise €450,000 in pre-seed investment to further its mission.
DIY hacks are another way to deal with coffee waste. Wynard Barnard, of Total Coffee Base, an online consumer guide, offers two tips: turn spent grounds into a household deodorizer or try them as an exfoliating skin scrub.
“To use coffee grounds as a body scrub, the first thing to keep in mind is that they should be finely ground. I mix half a teaspoon with my face wash, then gently apply the mixture to my skin in a circular motion. The used coffee grounds work as a natural exfoliant and leave my face feeling clean and smooth.”
To get rid of bad odors around the house, pour some used coffee grounds into a bowl or plastic bag, and place it strategically inside that smelly refrigerator, car, cat litter tray, or trash bin storage place. Wynand says it takes just a few hours for the grounds to leave the air smelling fresh.
Repurposing coffee grounds as compost, fertilizer or mulch is popular. But there are caveats. James Hyslop of The Coffee Folk, an online home-brewing guide, cites a thesis published in Urban Forestry and Urban Greening in 2016 which found that spent coffee grounds applied to soil reduced the growth of the five species of horticultural plants tested. Other findings have shown coffee grounds discourage seed germination and drive away earthworms, which are beneficial to plants.
On the other hand, spent coffee grounds can improve soil structure and reduce weeds, so they can be applied to fallow areas that will be planted at a later stage, Hyslop says. As for composting, a small portion of grounds can help create a mix of green and brown ingredients that will produce good results as a plant fertilizer.