- The UK produces 500,000 tonnes of waste coffee grounds a year, according to Bio-bean, which recycles waste coffee grounds into advanced biofuels and biochemicals
- Spent coffee grounds can be used in many ways. In the US, McDonald's started donating its used coffee grounds to community gardens and German company Kaffeeform uses them to create reusable coffee cups and saucers. Here, in the UK GroCycle uses them to grow oyster mushrooms, which are supplied to restaurants in the South West.
- Dried used coffee grounds work well in a rub for barbecued meat. As well as enhancing its flavour, the coffee's enzymes help make meat more tender. Pot Kettle Black in Manchester, for instance, uses coffee and chilli in a rub for brisket.
The UK is officially a nation of coffee drinkers.
Last year, we drank 95m cups of coffee every day, according to the British Coffee Association, and the coffee shop market is now worth over £10bn, a report by Allegra World Coffee Portal found
There's one downside to our love of coffee imbibing, however: the roasting process and the grounds used to make our brew create a large amount of waste – an estimated 500,000 tonnes per year.
Thankfully, the food sector is already on the case in finding ways to re-use coffee by-product – both before and after it's turned into a drink.
Coffee chaff – the parchment-like membrane that remains on the coffee seeds as it dries, also known as husk – is being used as an ingredient in bread by baker and coffee shop owner David Wright.
“Because we roast our own coffee, we have lots of chaff, and it seems such a waste to throw it out. I heard about places using it to make cookies and thought it would work well in bread too,” he explains.
Alex Bond, chef-owner of Nottingham’s plant-based fine-dining restaurant Alchemilla, “hates waste” so has been keen to find ways to cut it. An experiment with coffee grounds led him to create a dessert where coffee grounds are used to flavour the gelato and provide taste and texture within its garnish.
Before throwing nitrogen-rich coffee grounds onto his compost heap, development chef Hugh McGivern dries them out for culinary experimentation.
“My reasoning is that when you use a vanilla pod, it can be dried and used several times. I believe this can be done with the coffee grounds,” he says. “They can be used to infuse milk or cream to make cakes, flavour coffees and even a little in a beef stock. Then I throw them on my pile.”
Hugh McGivern, executive development chef at Lossiemouth House, uses coffee grounds in a mix for salmon gravadlax: “I've used coffee grounds for a while in my gardening forays and always add them to my compost pile, but since moving back to Scotland I've begun curing salmon in different ways, so I tried adding coffee grounds to my gravadlax recipe. I make the gravadlax in the classic manner with a 60/40 salt/sugar mix, which is scattered on a tray before laying the side of salmon down. A finely chopped mixture of chervil, dill, tarragon and flat parsley is smothered all over the salmon before it's covered in more of the sugar/salt mix. I then sprinkle about two to three tablespoons of coffee grounds over the top and refrigerate for four days. After four days, I wash off the grounds and the salt/sugar mix. The coffee grounds give the salmon a slightly earthy flavour with smooth vanilla tones in the background. To serve, I thinly slice two to three D-Cut slices of the salmon and serve it on toasted soda bread with some lemon soured cream.”
Alex Bond, chef-owner of Alchemilla in Nottingham, uses spent coffee grains in one of his desserts: “We use coffee grains left over from the coffee we serve in the restaurant to create a chocolate gelato, served with salted liquorice custard and beetroot sorbet. The gelato is made from a light, simple syrup infused with spent coffee grains, dark chocolate, cocoa powder and oat milk. The custard is a classic custard made with salted liquorice cream cooked over a bain marie, while the sorbet is beetroot cooked in sherry vinegar and blended with beetroot juice and sugar. The whole thing is covered in a dried porridge made from oat flour, dried spent coffee grains, water and butter, all cooked out like a porridge before we spread it thin and dry it out. The coffee grains provide a nutty, caramel and almost chocolate flavour and add texture to the porridge. I find that the bitterness of the coffee bridges the sweetness and earthiness of both the liquorice and beetroot. We call it ingredients bridging ingredients.’”
David Wright runs The Cake Shop Bakery and neighbouring cafe The Fire Station in Woodbridge, Suffolk, where he uses coffee chaff in a sourdough loaf: “I have developed a sourdough loaf using cold-brew coffee and the chaff from the roasting of the coffee in our roastery at The Fire Station. It’s dark, sour and fragrant. The recipe is a classic sourdough recipe with 80% white flour and 20% rye. I substitute 50% of the water for cold-brew coffee and add in chaff from the roasting process. It ferments for 18 hours before being baked. The chaff is the parchment-like membrane that remains on the coffee seeds as it dries. When roasted, the seeds pop or crack, releasing the chaff, and this is then extracted from the roasting chamber. The chaff lends a slightly sour taste and smoky flavour; it also helps with the colour of the bread. Along with the cold brew it really intensifies the coffee flavour in the bread.”