For every cup of coffee, 10 grams of coffee grounds are roasted, saturated and extracted. The average American will drink approximately 2 cups of coffee a day (at least!). Already in 1 wee,k each individual coffee drinker has used 140g of grounds… and it’s estimated that 64% of all American consumers drink coffee daily according to the National Coffee Association.
So, this got the Coffee Dorks team thinking. Can we reuse coffee grounds and reduce this monumental waste?
Can You Re-Use Coffee Grounds Multiple Times?
You can, but it just won’t taste the same. The first time we use coffee grounds, we carefully extract the oils, aromas and complex flavors. It’s a science that’s mastered – whether you make the coffee yourself or just use pods in a drip brewer. The brew ratio (volume of water/volume of coffee/extraction time) is delicately balanced to provide you with the optimum taste.
When we experimented with reusing grinds, the Coffee Dorks team found that you’re left with one of two results:
- The coffee is over extracted or burnt. This happened most when we re-used our coffee grounds instantly, making one cup straight after another. The resulting taste was very bitter, astringent and often burnt.
- The coffee is weak or dull in flavor. This resulted from leaving the coffee grounds to cool down and dry out a little between making coffee cups. Over time, the grounds continue to extract a little as they dry out. This really saps out the flavor!
As coffee enthusiasts, we were sorely disappointed by these results. The flavor was rather unappealing and the usual coffee aroma that we love was non-existent. If you want to reuse your grounds, don’t expect great things.
How to Re-Use Coffee Grounds
If, for whatever reason, you want to ignore our advice and reuse your coffee grounds again, follow these tips.
Let your grounds cool down. This will prevent them from burning.
Cover them as they cool. This will lock in as much remaining flavor as possible.
Don’t reuse more than twice. It just won’t taste nice and, trust us, you will end up throwing away the cup you make, wasting water as well as grounds.
Don’t tamp the second time. This only really applies to reusing coffee grounds for espresso. The grounds will already be weakened, wet and stuck together. Reusing them to make espresso isn’t going to taste good anyway, but tamping them further is just going to make it even more difficult for the water to extract though.
Can You Reheat Coffee?
In short, yes but you may regret it.
When we reheat coffee we basically remove all of the lovely coffee aromas, oils, and flavors that we worked so hard to get right. Furthermore, if you’ve already added milk, reheating it can actually curdle the milk, as we discovered for ourselves.
Also, it’s very likely that you’re going to burn your coffee if you use the microwave to reheat it. Instead, slowly reheat your coffee in a pan on the stove. Whatever you do, don’t boil it! It won’t taste amazing, but it will be drinkable and give you a small caffeine buzz.
If a zombie apocalypse is looming on the horizon and you really can’t venture out of the house to buy fresh coffee grounds, reheating a mug is forgivable. In all other circumstances, creating a fresh cup of coffee is the best and only way to make a coffee drink, whether it’s an espresso, latte or regular cuppa.
3 Cool Ways to Re-Use Coffee Grounds
Some of us had a great time trying out these cool coffee ground hacks. Keep a bowl or pot in your kitchen for storing the coffee grounds until you’re ready to use them. For some hacks you’re best using moist coffee grounds, others require the grounds to be dried out.
Coffee grounds are naturally acidic – use this to your advantage. You can use moist coffee grounds to fertilize flowers and vegetables you’ve got growing in the backyard. From magnolias to tomato plants and apple trees, your garden will be thriving.
Sprinkle the grounds around the soil where the plant is growing, or combine with soil to create a super-fertile compost for new plants. You could even try growing a coffee bush! Tropical climates at high altitudes are the optimum conditions for growing coffee, but you can still have a go at growing one in a greenhouse. You won’t get much of a harvest, but it’s still great to try.
Removing Smells… Or Creating Them
You might remember in our Why Your Coffee Tastes Bad article that storing fresh grounds in the fridge or freezer is a very bad idea. Even when sealed up, they can still soak up all the nasty smells lurking in the dark corners of the fridge.
Moldy veg, hunk of blue cheese or fish pie are the usual culprits of bad fridge odor. So, leave a pot of dry used grinds in the back of your fridge to eliminate those odors!
You can also use coffee grounds as an air freshener. This takes serious dedication to coffee – even some of the coffee dorks weren’t ready to have their homes smelling of coffee 24/7.
Improve Skin Care and Complexion
This is not the latest celebrity trend. Old coffee grounds have been used as skin care products for quite some time now. Here are a few ways you can utilize them.
Body Oil – Recent studies have further demonstrated that rubbing caffeine into the skin will eventually tighten it. When combined with quality olive oil, this mixture can do miracles for your skin if used regularly. It will definitely perform better than most $40 skin care creams you purchase at the local drug store. Give it a try!
Eye de-puffer – If you ever had a long night, whether drinking out with friends or working your life away, you probably experienced puffy eyes on the next morning. While this is not a serious condition, and usually goes away after a day of good rest – you can speed up the process.
Wrapping cold (not cool or room temperature) coffee grounds in a towel and placing them on your eyes for 20 minutes will do the trick.
Facial Scrub – Dead skin is the number one reason your face is not glowing. And I don’t mean dead skin in a zombie way. But, invisible to the naked eye layers of dead skin usually lurk around your entire skin, no just your face.
Rubbing coffee beans on your face will not help. However, if you have a facial cleanser, you can mix it with used coffee grounds and scrub away.
Coffee Soap – Going back to the previous point, coffee can be a very healthy for the skin. In addition, it turns out that coffee is a natural deodorizer. Hence, it has the ability to obliterate bad bodily smells.
Used grounds can be added to any soap, it is just not as easy to do it at home.
Around the House
We found a few creative uses of used ground coffee for small house based projects. This is nothing revolutionary, and we certainly did not come up with them. But, some of you might find them interesting.
Polish wood furniture – For this, you will need to soak the used grounds for a few hours before you do anything else. Next, filter the coffee into a large glass, add two tablespoons of strained mixture and 100ml or so olive oil. Stir the mix for 30 or so seconds. Make sure it is well-stirred.
Voila! You have a pretty solid wood furniture polisher.
Repair wood scratches – We came across people who claim to use coffee grounds to repair their old wooden furnishings. They claim that mixing used grounds with olive oil can make scratches go away. We did not test that, because we were too busy rubbing our faces with the very same mixture.
Repel or Attract Insects
Spiders hate citrus fruit… but not as much as some other insects (not including cockroaches) hate coffee. Dry out those coffee grinds and scatter them across windowsills to stop creepy crawlies climbing in at night time.
To trap cockroaches, fill a jar with coffee grinds that the insects can’t crawl out of. Leave overnight and by the morning you should have a jar full – repeat until your infestation has all but gone. You can also head back to the garden and scatter the grounds around plants you want to protect from slugs and snails.
To make sure you really make the most out of those coffee grounds before you re-use them, check out our coffee guides and tips on the coffee dorks blog.
Anthony is a professional barista in the city of Chicago. He has written for many online publications on various topics related to coffee.