Reusing Old Coffee Grounds

If you’re like me, you drink a lot of coffee. You might have had the same experience I have, feeling bad when you throw away filter full of used coffee grounds after filter full of old coffee grounds, wondering if there is any way you could avoid wasting them, perhaps even experimenting with some of the crazy-sounding uses touted on the internet. Coffee enthusiasts claim you can use old coffee grounds to fertilize your garden, as a pest repellant, a deodorizer, a cleaning agent, in a skincare regimen – I’ve even seen claims that you can use it to dye your hair.

I’ve only just started delving into the many ways coffee grounds can supposedly be recycled. Below, I’ll share my own experiences trying out some of the more mundane and somewhat zany claims.

To make more coffee

I’ve heard that some people have make more than one batch of coffee using the same grounds. I was a bit skeptical about this, but I do usually try to use my tea bags at least twice, so I thought I’d give it a whirl.

I first tried this with french press coffee. I made and drank my regular pot full, kept the grounds exactly as they were at the end, and just re-filled the carafe with hot water. I let it steep a bit longer than I let the first batch, assuming that it would need to in order for the water to absorb more of the flavor, like when you steep tea. The end coffee was still watery, tiny bits of grounds had floated into the drink, and the taste was off.

I then tried reusing my grounds in my drip coffee maker. I used half the water I’d used on the original grounds in the hope that it would it would make it less watery than my french press coffee had turned out, but – as you can see from the picture on the right – it didn’t help very much. This batch was even more watery-tasting – it seemed like it wasn’t coffee at all, but rather just coffee-flavored water. 

Overall, I wouldn’t recommend making a second batch of coffee with the same grounds. It’s definitely not the most effective way of reusing grounds.

In the garden

The most common way I’ve heard about people reusing coffee grounds is by using them in gardens. Many acquaintances of mine have suggested it – they claim they’ve done it themselves, and they rave about how much better their plants are doing since they started mixing grounds into their soil.

I’ve tried this on my houseplants, and had mixed results. Some of my plants really seemed to like the grounds, and did seem to get bigger and healthier – but, others died shortly after I gave them the grounds.

I wasn’t sure if they died because of the coffee grounds or because of my poor plant-rearing skills, so I did a little reading on the matter. It turns out that both might have factored into my plants’ deaths. Coffee grounds can be beneficial, but since coffee is acidic, it only helps plants that like acid. Adding grounds can hurt other plants – like my poor, deceased eucalyptus.

I only tried using grounds on my indoor, potted plants, so I can’t testify to the effectiveness of coffee grounds as a composted fertilizer or as an insect repellant, though I have heard that these are also major benefits to including them in your garden.

As hair dye

I once read that you could use coffee grounds to dye – or at least darken – your hair. This sounded a little far-fetched, but I did decide to try it out. I have naturally dark blonde hair and haven’t been brave enough to try actually dying it a different color. Coffee-dying is supposed to eventually fade out again, so I figured that if this worked, it would be a good way to temporarily try having darker hair. I already had the coffee grounds, so if it didn’t work, all I would lose would be a little time.

This was a couple of years ago, so I don’t remember the website I got the instructions off of or all of the details, but I do remember that the whole process was extremely messy. I created a mixture of grounds, conditioner, and brewed coffee, coated my hair in it, and twisted it all up in a plastic bag, and let it sit for over an hour, per the instructions on the website.

Assuming that this wouldn’t be an easy, mess-free endeavor, I initially applied the concoction in the shower, and I’m glad I did, because it was made an awful mess. Coffee grounds got everywhere!

In the end, the whole process had absolutely no affect on my hair color. It may just be my hair that resists color change – other temporary hair dyes I’ve tried also did not work on my hair – but it also could be that this is a bogus claim.

As an exfoliant

I first become curious on the exfoliating powers of coffee grounds after noticing how much softer my hands were immediately after I cleaned out our cold-brew coffee maker at work. It amazed me every time.

I did some googling, found that coffee grounds are actually pretty popular ingredients in homemade exfoliants, and decided to try making my own scrub.

I found one of many recipes touting the same basic ingreidents – coffee grounds, coconut oil, and sugar. I decided to include the optional cinnamon and vanilla, assumedly for scent, and added a couple of drops of tea tree oil, which is supposed to be great for reducing acne and fighting itchiness and dry skin, among a myriad of other dermotological benefits.

I dried out my coffee grounds out by spreading them out on a pan over some wax paper, and putting them in oven until they were nice in dry. Per the recipe, I melted the coconut oil, mixed in my grounds, spices, and oil, and put the whole thing in an old twist-off lotion container that sealed tightly.

During my next shower, I used on my arms, legs, feet, hands, and face, and afterwards my skin felt incredible. Seriously, I have never had softer skin than I did after using this scrub on it.

I will undoubtedly continue to make and use this scrub. I’ve even made some and given it away to friends, who also raved at it’s effectiveness. It’s super easy to make, and barely takes any time at all. The only major downside is the mess that it makes and how hard it is to keep large amounts of grounds from going down your shower drain.

Conclusion

Have you tried any of these? Did you have the same, or different results? Have you discovered another way to use old grounds? Please, share below!

13 Replies to “Reusing Old Coffee Grounds”

  1. Amazing post with a great read! Your experience with coffee to darken your hair have made me eeek as I myself tried this and went through similar experience and emotions, so NEVER again, lol.

    I enjoy the aroma of freshly brewed coffee.

    Thank you for this great sharing.

    Best wishes

    1. Oh wow, I’m glad I’m not the only one who’s tried it unsuccessfully! It’s definitely not something I’ll be trying again either, unless I find out about some revolutionary technique that makes it a lot less of a painful process – and that there’s a way to increase effectiveness, I guess? Did it darken your hair at all, or was it as unaffected as mine was?

  2. Very interesting! I love coffee and always feel bad tossing the used grounds. I researched about putting them in the garden and it could be harmful due to the caffeine. Thank you for a great article.

    1. Ah, the caffeine, too? I know very specific plants are supposed to respond very well, but the ones I tried it with did not seem to like it very much. Have you tried it before?

  3. I know several master gardeners that use coffee grounds on certain plants (especially tomatoes). I know it helps with some bugs and critters because of the intense scent, but I don’t know that they use only grounds for bugs.

    I will have to try that scrub. I have tried something similar on my face only and I just remember the mess, but it might be worth it all over once in a while.

    1. I have heard that it works well as an insect repellant, but I didn’t really experience that with my houseplants. I have heard that it is super awesome for plants like azaleas, but I suppose tomatoes would be good too. I think it’s just important to do some research before mixing them in with any old plant – as I definitely should have done.

      I highly recommend that you do try the scrub! Weirdly enough, I feel like my face was wear I felt the difference the least. But even if you just use it on your hands – it works better for me than any lotion.

  4. Oh, I’m a huge coffee lover, too. I also tried to find a use for the used grounds some years ago, but was only able to use them with my plants. Similarly as you say you are, I’m not so good with plants. None of them actually died, but have not benefitted from the coffee either, as far as I could tell. So, I eventually gave up and went on tossing out the huge quantities of coffee grounds. The hair dying-I’ve never heard of it and I can only imagine the mess one makes by it. This scrub of yours is intriguing, though…

    1. You should try it! I think I’m actually going to make another batch. When I do, I’ll add a picture to this post.

      I’m glad your plants didn’t die from the coffee 😀

  5. Thank you so much for this highly informative article! Though I am not a coffee drinker (I drank a lot of it in high school and college, and stopped cold turkey my junior year of college), my family certainly is, and I’ve seen them try all of these options before! Two of my cousins tried to use coffee grounds as hair dye (they both have light brown hair), and it actually did turn their hair a darker shade of brown, though their hair became slimy and strong smelling. My aunt regularly uses coffee grounds in her daffodils and camellias, and I must say, her flowers are growing like crazy (they’re saying it loud; we’re colorful flowers, and we’re proud! Haha). Great read! God bless you!

    1. Wow, I have so many questions, as I’ve never heard of anyone actually being successful with the hair dye! What was your cousins’ secret?! Do you know how they did it? Did the color fade quickly? Did the sliminess and smell go away after washing it?

      I assume those are both acid-loving plants? I definitely need to do more research on which plants like acid before trying that again.

  6. The environmentalists and eco warriors would love this post. Reusing old coffee grounds sounds as if the sky is the limit. I never considered doing anything other than making compost with them, so this article was an eye opener.

    Great read!

    1. I’m glad you enjoyed it! Hopefully it steered you away from the hair dye idea and towards something that will be useful for you 😀

  7. Hi! Thank you for the interesting post! Personally, I have never tried to reuse the old grounds, but I like your advices, especially about making your own scrub, I will definitely try it! I think we need to recycle everything we can in order to help our planet. I read an article about making glasses using special technology from the old coffee grounds.
    All the best,
    Alex

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