If you drink coffee you create used coffee grounds. But they don’t need to end up in landfill.
In the English seaside town of Brighton, the Espresso Mushroom Company has turned something that is normally discarded into an asset.
Twice a week it collects used coffee grounds from up to 10 cafes in the town. That is the equivalent of about 200 kilograms a week – or almost a tonne a month. Those coffee grounds are then taken to a farm, where they are used as compost to grow mushrooms.
The company’s Robbie Georgiou explained: “Every day, tonnes and tonnes and tonnes [of used grounds] – hundreds of tonnes, probably – nationwide are being thrown straight into landfill. This is unnecessary, and in fact it really is a waste because, as we’ve shown, this is a resource.”
When a cup of coffee is made, less than one percent of the coffee beans end up in the cup. The spent grounds are still packed full of cellulose, lignin, nitrogen, sugars and other nutrients which the mushrooms can make use of.
Six kilos of used coffee grounds – the equivalent of about 100 shots of espresso – are mixed in bags with a handful of grain containing mushroom root added. The bags are then numbered and dated, and placed in a dark room. Within two weeks – and after twice-daily watering – the mushrooms are fully grown and ready to be harvested.
Each bag typically yields between 150 and 200 grams of mushrooms and sometimes more. There are two kinds of environmental benefits: the coffee waste are not going straight to landfill and it curbs the emissions of methane – a major greenhouse gas that is produced when coffee degrades normally.
Georgiou said: “Mushrooms are essentially nature’s recyclers in the outdoors. They break down organisms and matter, and turn it back into nutrients for other organisms to use. So, in that sense, it’s breaking down the coffee and then using it as a food for which to grow food for us.”
After final checks to ensure the mushrooms are in good condition they are ready to be sent out to customers.
So – the big question is what do they taste like? Robbie Georgiou’s brother Alex, who works with him in the company, explained: “The fact is the growing medium of the mushrooms does affect the flavour and also the freshness that you get. When you grow your own mushrooms at home it really gives it something that you just can’t buy from the shops.”
The business has been going for some years, and with many companies and individuals around the world using the same technique, in the future most of the mushrooms we eat will come from coffee waste.