What to do with used coffee grounds
As with many of my posts, this article will evolve over time as new ideas for what you can do with used coffee grounds present themselves. Please keep in mind many of these ideas are based on the question of “what can I do with all these free spent coffee grounds I keep producing?” Rather than for example what is the best way to fertilize my plants. Coffee is probably not the best fertiliser but in some instances, it could be used if you have some for free grounds but don’t go out buying bags of used coffee for this purpose.
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Knock box to put your used espresso coffee grounds in
First things first if the majority of your coffee is coming from making espresso, instead of the spent coffee from the portafilter going into the bin, you need to get yourself a knock box. Well “need” is probably a little strong but they are definitely a good idea as you can place it next to your machine. Then as soon as you’re ready, take the portafilter and bash it on the knock box and out, comes the puck of used coffee….Very satisfying and makes you feel like you are are real barista in a cafe.
I will do a proper review of the knock box but, to be honest, it’s just a bucket with a knock bar. Yes some are higher quality, have a removable bar and some have a degree of shock absorbency but the most important fact is how it looks next to your coffee machine. My overall favorite is the Breville-BES001XL-Knock-Box mainly because I like the square shape and it goes with my barista express machine, but here is a quick selection of my top picks which covers the different styles available.
What to do with used coffee grounds in the garden
- Provide nutrients for your plants: Coffee contains nitrogen and can help with drainage & water retention. So either place some coffee grounds around your plants or better still mix it into the soil around your garden to add these nutrients/benefits to the soil. But you still need to factor in all the usual things you would otherwise consider when looking after your plants such as the make-up and acidity of the soil. Coffee is generally on the acidic side of the scale but can actually be slightly alkaline so you need to test it and check what kind of soil your plants require. But generally, if you don’t put too much coffee into your soil and just add a small amount around your plants it should add nutrients without doing too much harm even in the worst case scenario.
- Discourange bugs from eating your plants and vegetables: Another potential benefit of coffee in the garden is that it is said to discourage insect nad bugs such as slugs from climbing on and eating your plants. Please note coffee does not kill slugs and may not actually stop them in their tracks but some info suggests they are not keen on it so may avoid if they can.
- Insect repellant: As well as placing it on the soil you could actually place some used coffee in bowls/ tups around your garden to repel insects like mosquitos.
- Composte and Encourage Worms in your soil: Worms love ground coffee so adding it to your soil will encourage more worms into your garden and the benefits that worms bring to your plants. Also ideal for adding to your compost bin so that the worms can break it down and turn it into compost for your garden.
What to do with used coffee grounds in the house
- Odour Neutralizer: The reason why we have to be careful about how we store our coffee beans before we use them is that reason that the spent coffee grounds become a great odor neutralizer. I.e. If you leave you coffee beans exposed to other foods that have a strong smell, your coffee bean will absorb these odors. Obviously you don’t want this to happen before you use them to brew your coffee, But once the coffee has been used you probably don’t mind it absorbing all the odors its wants. For example, you could add some used coffee to a bowl and place it in the fridge to absorb any smells that might be in there.
- Exfoliator / Scrub cleaner: Coffee grounds provide abrasive properties to help clean certain surfaces or even use as an exfoliator for your skin.
Ideas for grounds from a plunger or french press
Unlike used coffee grounds from and Expresso machine which are quite dry and can easily be left to try out fully, french press grounds will be on the more wet side. This makes them ideal for adding to soil and will also add some moisture to your plants
Coffee grounds are ideal for growing mushrooms
Unlike other ideas above, coffee grounds actually provide a good environment for growing mushrooms. I have even seen businesses built on this fact. One such company went around collecting used coffee grounds from all the local cafes and then used it to grow mushrooms, which were then sold to local restaurants.
How to use or get rid of large quantities of coffee in a sustainable way
If you are a cafe or business that produces a large amount of coffee ground it is imperative that as little of this ends up in landfills as possible, especially when there are so many valid ways people can use spent coffee grounds. This is where companies like reground can help. They collect used coffee from coffee shops and repurpose it for fertilizer and other uses. According to their website as of Jan 2020, they have saved nearly 500 tonnes of ground coffee from going to landfill, which is an amazing effort. I think you can even get hold of some of this for free if you want to use it for some of the ideas above but don’t produce enough of your own.
Video also includes additional great ideas for used coffee grounds
