Concept

1. Saving the waste
We collect spent coffee grounds from collaborating cafés and restaurants located in Carcassonne. The high temperature used during our partners coffee brewing process guarantees that the coffee waste is contamination-free.
2. Time to inoculate
Collected coffee grounds are mixed together with silverskin of coffee bean and mushroom spores in a sterile environment. Later breathable plastic bags are filled with evenly mixed substrate.
3. Incubation period
The bags are left in a dark room for 2-3 weeks until mycelium colonises the coffee grounds and spreads throughout the bag, changing its colour from dark brown to white.
4. Fruiting - magical time of the process
Once mycelium takes over the substrate it is time to get the bags to a clean, light, fresh and humid environment to stimulate mushroom growth. Fruiting is the time when magic happens. In just a few days (!) fully grown Oyster mushrooms can be harvested.
5. Back to the roots
After mushroom production, the remaining coffee waste and mycelium goes to the Vermicompost, where worms convert it into fertile soil amendment.
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Why recycle coffee grounds?

Currently, coffee consumption and production lead to 15 million tonnes of used coffee grounds and 0,18 tonnes of coffee silverskin. Since the coffee waste contains high quantities of organic material, it is a major pollutant. In fact, when this coffee waste is not recycled and goes into landfills, methane gasses are produced. In addition, compounds that are present in coffee waste, such as caffeine and polyphenols, have been proven to be ecotoxic. Therefore, coffee grounds must be recycled as efficiently as possible.

Why recycle coffee grounds?

Currently, coffee consumption and production lead to 15 million tonnes of used coffee grounds and 0,18 tonnes of coffee silverskin. Since the coffee waste contains high quantities of organic material, it is a major pollutant. In fact, when this coffee waste is not recycled and goes into landfills, methane gasses are produced. In addition, compounds that are present in coffee waste, such as caffeine and polyphenols, have been proven to be ecotoxic. Therefore, coffee grounds must be recycled as efficiently as possible.

Why use coffee grounds for oyster mushroom cultivation?

Currently, coffee waste is often used as a bio-fertilizer since it contains high amounts of organic matter and nutritive elements. Furthermore, the coffee waste increases the soil microbial diversity. However, as mentioned before, several studies have shown that used coffee grounds in itself can be unbeneficial for plant growth since high caffeine and polyphenol concentration is toxic for plants. Interestingly, oyster mushrooms (Pleurotus) can take up and break down this caffeine. In turn, by growing oyster mushrooms on the coffee waste, we can lower the toxicity for plants by reducing the amount of caffeine in the coffee waste. As a result, we benefit twice from recycling coffee waste to grow oyster mushrooms. We obtain oyster mushrooms for consumption using coffee waste as a growing medium, and we increase the coffee wastes bio-fertilizer value by lowering the caffeine concentration.

Why use coffee grounds for oyster mushroom cultivation?

Currently, coffee waste is often used as a bio-fertilizer since it contains high amounts of organic matter and nutritive elements. Furthermore, the coffee waste increases the soil microbial diversity. However, as mentioned before, several studies have shown that used coffee grounds in itself can be unbeneficial for plant growth since high caffeine and polyphenol concentration is toxic for plants. Interestingly, oyster mushrooms (Pleurotus) can take up and break down this caffeine. In turn, by growing oyster mushrooms on the coffee waste, we can lower the toxicity for plants by reducing the amount of caffeine in the coffee waste. As a result, we benefit twice from recycling coffee waste to grow oyster mushrooms. We obtain oyster mushrooms for consumption using coffee waste as a growing medium, and we increase the coffee wastes bio-fertilizer value by lowering the caffeine concentration.

Why grow oyster mushrooms?

Oyster mushroom is an edible mushroom that got its name because of its similarities in color and shape to oysters. Like other mushrooms, oyster mushrooms are low-calorie, low-fat, fibre-rich and high in vitamins and minerals. The nutritional values in 100 grams of oyster mushrooms are 19-35% protein, 1.7-2.2% fat, carbohydrates, vitamin B, vitamin D, vitamin C, and minerals such as copper, phosphorus and potassium.

 

Next to their nutritious value, oyster mushrooms are believed to contain health benefiting substances such as dietary fibres and Beta-glucan. First of all, one study found that dietary fibre components in oyster mushrooms have a cholesterol-lowering effect. Secondly, Beta-glucan and several other polysaccharides, which are present in oyster mushrooms, are shown to strengthen the immune system. Lastly, a recent preliminary study suggested that oyster mushrooms exhibit cancer inhibitory effects.

 

Another advantage of oyster mushrooms is their ease of cultivation. Oyster mushrooms are one of the easiest to grow mushrooms since they can be grown on a range of different substrates such as sawdust, wheat straw, cardboard and coffee grounds. Furthermore, oyster mushrooms are the fastest-growing edible mushroom whereby the mushroom size doubles every 24h during the fruiting stage. The last major benefit of oyster mushrooms is their resistance against competing fungal moulds.

Why grow oyster mushrooms?

Oyster mushroom is an edible mushroom that got its name because of its similarities in color and shape to oysters. Like other mushrooms, oyster mushrooms are low-calorie, low-fat, fibre-rich and high in vitamins and minerals. The nutritional values in 100 grams of oyster mushrooms are 19-35% protein, 1.7-2.2% fat, carbohydrates, vitamin B, vitamin D, vitamin C, and minerals such as copper, phosphorus and potassium.

 

Next to their nutritious value, oyster mushrooms are believed to contain health benefiting substances such as dietary fibres and Beta-glucan. First of all, one study found that dietary fibre components in oyster mushrooms have a cholesterol-lowering effect. Secondly, Beta-glucan and several other polysaccharides, which are present in oyster mushrooms, are shown to strengthen the immune system. Lastly, a recent preliminary study suggested that oyster mushrooms exhibit cancer inhibitory effects.

 

Another advantage of oyster mushrooms is their ease of cultivation. Oyster mushrooms are one of the easiest to grow mushrooms since they can be grown on a range of different substrates such as sawdust, wheat straw, cardboard and coffee grounds. Furthermore, oyster mushrooms are the fastest-growing edible mushroom whereby the mushroom size doubles every 24h during the fruiting stage. The last major benefit of oyster mushrooms is their resistance against competing fungal moulds.

What purpose has the coffee waste after oyster mushroom cultivation?

Once the oyster mushrooms are harvested, the oyster mushroom cultivation medium containing the coffee waste is recycled once again into vermicompost. Vermicomposting is the use of earthworms in combination with fungi and bacteria to turn organic waste into natural fertilizer. Vermicompost is a valuable soil amendment since it contains high nitrogen, phosphorus, and potassium levels. Furthermore, vermicomposting stabilizes the soil’s pH and improves the soil’s structure. In addition, the present microorganisms can guard the plants against a variety of infectious diseases. Interestingly, the vermicomposting process, further breaks down phytotoxic and ecotoxic compounds such as caffeine. In turn, the plant growth will not be inhibited by the caffeine anymore, improving the potential of the vermicompost generated using the coffee waste.

What purpose has the coffee waste after oyster mushroom cultivation?

Once the oyster mushrooms are harvested, the oyster mushroom cultivation medium containing the coffee waste is recycled once again into vermicompost. Vermicomposting is the use of earthworms in combination with fungi and bacteria to turn organic waste into natural fertilizer. Vermicompost is a valuable soil amendment since it contains high nitrogen, phosphorus, and potassium levels. Furthermore, vermicomposting stabilizes the soil’s pH and improves the soil’s structure. In addition, the present microorganisms can guard the plants against a variety of infectious diseases. Interestingly, the vermicomposting process, further breaks down phytotoxic and ecotoxic compounds such as caffeine. In turn, the plant growth will not be inhibited by the caffeine anymore, improving the potential of the vermicompost generated using the coffee waste.