Coffee, Mushrooms, and Buses: What's the Connection?

Person enjoying a cup of coffee

Like many people, I brew a pot of coffee every morning. But let's take a few minutes to consider the amount of waste generated as a result of this extremely popular habit.

Headed to a landfill near you

Even the most eco-conscious coffee aficionados among us may not be doing enough to prevent used coffee products from ending up in a landfill.

Approximately 1,322,760,000 pounds of spent coffee grounds are added to the world's landfills every year. That amount is equal to the volume of the Great Pyramid of Giza. And it doesn’t include natural waste by-products, such as coffee berries and unused seeds.

take out coffee cups

Harmful environmental effects

Animals and plants feed on the coffee waste humans generate. The amount in landfills can have major effects on them, including death.

Discarded waste by-products of coffee drinking are likely to end up in a landfill somewhere and begin to break down, becoming extremely toxic and a potential health threat. Over the span of a hundred years, they will continually emit greenhouse gasses, including methane, at a potency 34 times higher than carbon dioxide. They are also highly acidic which leaches into the soil and causes an imbalance.

Are you possibly contributing to the situation? If so, a few changes will allow you to consume as much coffee as desired while at the same time helping mitigate the problem.

coffee and coffee filter

The connection between coffee and mushrooms

Growing mushrooms in coffee grounds doesn't require any expensive equipment. All you need are some growing bags and a container for mixing mushroom spawn with the grounds.

Many varieties grow well this way. However, it's important to pay careful attention to the cultivation process.

coffee with question marks

How to grow them

Button and oyster mushrooms are two of the easiest to grow on coffee grounds. Both are versatile, flavorful, and very nutritious.

Use clean equipment and rubber gloves to mix mushroom spawn with the used grounds. Dampen with clean water.

Here are special grow-bags where you can grow your own tasty mushrooms.

mushroom grow bags

(Mycotechmushroomlab, CC BY-SA 4.0, via Wikimedia Commons)

Cut a small hole in the growing bag and place it in indirect sunlight for two or three days. Spray with water daily.

Then leave the growing bag in a dark, warm place for 2-3 weeks. Check frequently for the presence of white mycelium. This network of white roots is the main organism from which mushrooms develop. By the end of the second or third week, the bag should be full of bright white mycelium.

Mushrooms will begin growing in 5-10 days and grow very quickly, approximately doubling in size each day. Spray with water twice a day for the next 5-7 days. If mold appears, spray less often.

mushrooms growing

Harvest when the caps begin to flatten. Cut off the cluster with a knife or simply twist it. After two days, submerge the bag in water overnight to rehydrate the growing medium. This will often result in a second crop.

Get started with this white button mushroom spawn.

Make compost

One of the best ways to use spent coffee grounds is composting. Put grounds in the sun for approximately a month. This allows microorganisms to break them down.

They can also be used for worm farming (vermicomposting). Earthworms are one of the fastest composters known and will efficiently break down the coffee. Spread in the garden or use on your potted plants.

Abundantly healthy

Mushrooms are both low in calories and high in nutritional value. They're loaded with vitamins, minerals, and antioxidants, and have long been recognized as a beneficial addition to a healthy diet. Mushrooms grown with exposure to ultraviolet light are a good source of Vitamin D, an important element for strong bones and a healthy immune system.

Fueling buses

city bus

As the world struggles with climate change, the need for clean renewable energy and fuel sources has become urgent. One popular option, biofuel, is already being produced from food crops. However, it's costly and competes with food production for land use, water, energy, and other environmental resources.

The journal Science Advances recently revealed that a naturally-occurring bacterium (Thermoanaerobacterium) derived from waste generated after harvesting mushrooms is capable of directly converting cellulose to biobutanol, a fuel that can be used in vehicles that are currently on the road.

Any biofuels sourced from agricultural, horticultural, and organic waste must be able to meet growing energy demands without increasing greenhouse gas emissions that result from burning fossil fuels. Biobutanol sources are abundant, environmentally friendly, and sustainable and could directly replace gasoline in cars without the need for engine modifications.

Where did coffee originate?

Of the many stories regarding the origin of coffee, one of the most popular is that of a young Ethiopian goat herder named Kaldi. When he noticed how energetic his flock became after chewing on some local berries, he brought them home and used them himself.

Kaldi the goat herder

Kopi Luak - the most expensive coffee in the world

This coffee's unusual method of production uses palm civets, small animals that eat and digest coffee cherries. They eventually, well, poop the beans. The finished product can cost over $625 a kilogram.

What many people don't know is that many civet farms keep animals confined in small metal cages without access to adequate water or sunlight. These civets display signs of extreme stress. Is any coffee really worth the suffering?

(above: palm civet; Jordy Meow, CC BY 3.0, via Wikimedia Commons)

Coffee can lengthen your life

Due to its antioxidant properties, coffee is one of the healthiest beverages in the world. As part of a healthy lifestyle, it can extend your lifespan.

The takeaway: drink all the coffee you want without feeling guilty by finding ways to safely reduce your coffee waste.

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