Coffee Grounds Recycling Innovations: From Biodiesel to Yummy Coffee Bars 

Coffee Grounds Recycling Innovations: From Biodiesel to Yummy Coffee Bars 

With how more people consume coffee each day, coffee grounds waste also increases. In UK only, people consume around 98 million cups of coffee each day. 

Not blaming anyone, of course, I myself understand the need for this caffeinated drink. It’s just that much of the waste used to be simply dumped in landfills or incinerator. 

Thankfully, there are many large-scale ways to upcycle the waste nowadays, like mentioned in this article. 

Nonetheless, to appreciate technology, human minds, and hope in a more environmentally friendly future, here are some recent innovations that recycle coffee grounds. 


Making biodiesel by feeding coffee grounds to microalgae 

In order to know what else can algae and used coffee grounds can do, researchers from Aston University tried feeding coffee grounds to growing microalgae. 

The researchers were a part of a team that grew algae which would be processed into fuel. 

They found that leftover coffee grounds actually provide not only nutrients to the microalgae, but also a structure where it can grow. 

Therefore, the researchers could extract an enhanced version of biodiesel with minimal emissions as well as good engine performance. This fuel also meets the US and European requirements. 

So far, we grow algae on polyurethane foam and nylon which don’t provide nutrients. But through this research, it’s discovered that microalgal cells can in fact grow on used coffee grounds without needing other external nutrients. 

And by exposing the algae to light for 20 hours a day and dark for four hours, the algae create the best quality biodiesel. 

One of the researchers said that this discovery could provide an ideal choice for new feedstock commercialization, decreasing the growing (and deforestation to its extent) and cutting down palm trees to extract oil to produce biofuel. 


Palm oil alternative 

Speaking of palm trees and palm oil, there’s a patent-pending method that’s able to recycle coffee grounds into a sustainable palm oil alternative. 

This process or method is developed by Revive Eco, a Glasgow-based green tech startup launched in 2019. It’s actually an extension of a project that the founders undertook during their undergraduate degree as they worked in coffee shops in the city. 

Annually, it costs around £80 millions for the coffee industry in waste removal, and the UK produces 500,000 tonnes of used coffee grounds.  

So, the startup extracts high-value, natural chemicals from the grounds into a material substituting palm oil which one can use for cosmetics, home cleaning, pharmaceutical, and FnB industry. 

After securing funding, the investors that include Gabriel Investment Syndicate, Scottish Enterprise, and the University of Strathclyde will support the startup to commercialize its technology and scale up the manufacturing capability. 

Revive Eco will begin trials with some big brands in the UK and across Europe, hoping to announce a series of partnerships and contract wins in 2023. 

Cofounder Fergus Moore said, “With the rise of ESG, corporations and manufacturers are under increasing pressure to find alternatives to palm oil, so the moment for us to help bring about change is here and now.” 



Yummy coffee bars using used ground coffee 

According to Tetsuji Ishigaki, it’s possible to recycle used ground coffee without unwanted residue or emissions that will end up harming the environment all the same. 

In order to know if it’s possible to upcycle the coffee grounds with no negative environmental impact, the Japanese scientist experimented with koji, a beneficial mold used to make traditional Japanese fermented foods like soy sauce and sake. 

Ishigaki took used coffee grounds from a local café and experimented by fermenting them with koji to make a paste. He then pasteurized and processed the paste into coffee bars called COLEHA. 

Ishigaki said, “To make the paste, we added water to the coffee grounds with a 2:1 ratio. COLEHA is made by adding cacao butter to the paste to solidify. 1kg of coffee grounds can produce 115 bars.” 

The COLEHA bars are available in three different types, ranging from 0% to 40% sugar. Already launched months ago, each bar costs 800 yen or around $7. The bars have been sold out regularly. 

Reviews say that COLEHA bars are all tasty. The 0% sugar type coffee-flavored dark chocolate with the slight acidity of high-quality coffee. Fruity, milky taste is found in the 10% sugar variant, and the 40% sugar kind has a caramel note.  

Even though all COLEHA bars have a thin, crumbly surface, it quickly melts in your mouth once you bite it, together with a strong coffee taste. Perfect for coffee lovers, particularly the eco conscious ones. 

The secret behind the delectable used ground-coffee bars 

By now, we know the meaning of “umami,” a savory, rich, delicious taste. Koji is famous for creating this taste because it produces enzymes that convert protein into amino acids—a primary source of umami. 

Ishigaki’s lab analysis shows that the coffee paste contains approximately 3 times more amino acids than raw coffee beans. The scientist assumes that koji adds the rich taste to the coffee grounds. 

Now, even though COLEHA bars are delicious and made from “waste,” there are some potential health benefits.  

According to Ishigaki, lab analysis also shows that the coffee paste contains 1.6 times more polyphenols, health-promoting compounds and 1.78 times more antioxidants than regular coffee. Moreover, 94% of the coffee paste is an insoluble fiber that may promote gut health. 

You may ask, “Okay, the bars taste really good, they may have health benefits, and they’re eco-friendly. But could it help me stay alert or energized?” 

A single bar (22 grams) contains 50mg of caffeine, which is around half of a regular cup of coffee. So, you can easily eat it with your own cup of joe for breakfast or a little snack that help you stay awake in times of need. 

Hopefully, Ishigaki could produce COLEHA globally so that we all could enjoy some delicious coffee bars made from leftover coffee grounds. 


Remember that we can recycle grounds at home 

All the mentioned innovations above are certainly cool they make us hopeful about the future. In fact, there are actually a lot of other processes out there that use leftover coffee grounds. 

Though, we must note that they’re not all widely available to us, and some haven’t been tested for large scale production yet. 

In the meantime, we can always try to recycle coffee grounds from our own domiciles. Here are some easy ways to upcycle them.  

Oh, I must remind you beforehand that in all the DIY project ideas below, you need to dry your used ground coffee first. 


Make coffee candles or soaps 

Why not make your house or room smell great with your own DIY coffee candles? You don’t always need to buy wax to make these candles, you can always use stumps of old candles and melt them together in a pot and then mix in some coffee grounds. 

Or, you can make yourself smell great by making some coffee soaps and then use it. Sometimes it’s a little more complicated when making soaps, so make sure that you got the recipe right. 



Scrub for (almost) everything 

Since coffee grounds are coarse, it’s perfect to be made into scrubs for nearly everything, like body and face scrub, scrub to help clean the bottom of your pans, and one that I’ve just found out and fitting for this season: fireplace. 

Cleaning fireplace can be bothersome because the ashes can spread all over the house. To reduce that, we can firstly mix coffee grounds with some water so they’ll become heavier. 

After, spread the ground coffee paste on the bottom of the fireplace and mix it with the ashes. This way, the ashes won’t rise and we can simply remove them with a brush or broom. 

Now, when it comes to cleaning items and not our body, we must remember that the grounds won’t magically make them sparkly, squeaky clean. But, they help, at the very least. 


Natural odor absorber 

Start saying bye-bye to odorous shoes by filling a sock with used coffee grounds and leave them overnight inside the shoes. If the problem is in your feet, remember the body scrub. 

You can also use the grounds in ill-smelling fridge. Similar to using baking soda, you can fill a mason jar with used coffee grounds and simply leave it in the fridge. 

To make your microwave smell fresher, mix half a cup of water and two tablespoons of leftover ground coffee, then place it in the microwave for less than a minute. 


These are just some ideas; you can look for more on the internet. What’s important is that we don’t throw away coffee grounds after enjoying our cups of coffee. So, we can all take part as coffee lovers that also care about the environment. 



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