Mikkel Lustrup (left) and Ebbe Korsgaard (right) showing oyster mushrooms grown on local coffee waste in Copenhagen René Georg Johansen

Beyond the Bean: Turning Coffee Grounds Into Protein Powder

When you make coffee, you're using only 0.2% of the bean's biomass. You can grow mushrooms on the coffee waste and produce umami-flavored protein while about it

Impact Journalism Day: Today, 50 of the world's leading medias highlight positive innovations that are changing the world.

The container in the parking lot was filled with black plastic bags which in turn were filled with discarded coffee grounds. Clusters of oyster mushrooms grow out of the sides of the bags.

Tobias Lau, who partnered with Thomas Harttung, co-founder of the organic food supplier Aarstiderne, to create the company Beyond Coffee in 2016, breaks off a mushroom. “Try a sample,” he says.

It tastes terrific and has great texture.

Mushrooms are nice. But the team of scientists led by Professor Lene Lange from the Technical University of Denmark (DTU) has been studying Beyond Coffee’s project, which is funded by a grant from the Innovation Fund  Denmark, bec of the mycelium: the network of white fungal hyphae growing inside the coffee grounds.

Mycelium is a goldmine for protein. The scientists are eager to harvest the proteins and convert them into a powder to enrich feed and foods.

Ahead of a visit with his new associates at DTU, Lau takes a bag brimming with oyster mushrooms down from a meat hook and attaches it to the ceiling of his small delivery van parked by the container. We then head to the university.

“When you pour boiling water over the crushed coffee beans and extract the taste from them, you only use 0.2 percent of their total biomass. We use the remaining 99.8 percent to grow food in the form of oyster mushrooms. But the fruiting bodies emerging from the bag only comprise the tip of the iceberg; the mycelium is an untapped resource, and we would like to get our hands on it before the mushroom-enriched coffee grounds either end up being used as fertilizer or are sent to a biogas facility or an incineration plant,” says Lau, who was inspired to contact professor Lang after hearing her on the radio.

When we arrive in the lab at DTU, PhD student Bo Pilgaard is tasked with opening the bag, having done it before as part of his PhD project. Once exposed, the coffee grounds reveal a myriad of white hyphae.

Pilgaard digs into the coffee grounds, which resemble dry soil, and crumbles them into a foil tray. He moistens the coffee grounds with tap water and places the tray into an airtight plastic bag.

“Now the tray has to sit in a heating cabinet set to 17 degrees Celsius, and after a week we will have a thick, white layer of mycelium bursting with proteins,” says Pilgaard.

Like in cooking shows, he has prepared the end result in advance. Next to him is a similar tray, which looks as if it contains cake.

“We are very close to the finish line with our pilot project. If we dried the white layer of mycelium in the tray and crushed it, we would get a protein powder with umami flavor,” says Lang. 

The professor also believes that the protein powder could be used to improve the taste of plant-based meat substitutes, and infuse them with more proteins.

“If you want a climate-friendly diet, there is a tendency to think that it is okay for it to have a boring taste. It is our ambition with our climate-friendly protein powder to produce food products such as soups, health drinks, sauces, bread, pizza toppings and porridge that taste better than anything you have tried before,” says Lange.

For this reason, the scientists have partnered with Matt Orlando, chef-owner of the Danish restaurant Amass and a former chef at Noma, one of the world’s most famous restaurants. He will be conducting experiments to find out if the new protein powder can be used to create delicious dishes.

Usually, it takes a long time before new research discoveries find use in the real world. But Lange is optimistic.

“When we are approved by the food authorities, we will gradually start distributing our product to consumers. Thanks to our collaboration with Beyond Coffee, we have a platform that allows us to reach Danes who are motivated to try new things,” she says.

“If we are to have any hope of feeding the increasing number of people on our struggling planet, we need to find better ways of making the most of our resources. In this struggle, mushrooms are vital.”

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