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How to Store Used Coffee Grounds +Reuse Tips

By: 21 Comments

How to Store Used Coffee Grounds

I love used coffee grounds and save them.  As Tony the Tiger says, they are GREAT in the garden.  In fact I bet you didn’t know that I was a frequent stalker at Starbucks waiting for them to put their used grounds in the gardener bin pick-up?  Unfortunately, I was competing against super gardener athletes whose keen sense of used coffee grounds beat me every time to the bin.  Sadly, I am only left with coffee grounds that hubs drinks.  So you can imagine my horror when I  ruined my stash more than once and learned the hard way how to store used coffee grounds.  Be sure to watch my video below!

PS You will also learn how reuse them as well.  So read on.

Anna, why are you obsessed with coffee grounds?  You can’t reuse them for drinking.

I know. I tried that once.

*Meh.*

That is all I have to say.

Why I Love Coffee Grounds–Ways to Reuse Them

Just in case you want to know why I love coffee grounds so much, read my multiple articles.  Coffee grounds are a gardener’s best friend IF used right.

If gardening isn’t your thing, here are some other articles on other ways to reuse your coffee grounds:

I told you I love coffee grounds.  The smell is heavily even though I don’t drink coffee.

How to Store Used Coffee Grounds Properly

If you live in an area of the country that is cold in the winter, going out to the composter may not be an option. I store mine in leftover containers for use in the garden in the spring.  Lately, I have been stockpiling the grounds since I have illusions that I will be making some products with the grounds.

Anna, you spend waaay to much time in your garden to even think about using those grounds other than for the garden.

Yeah, I know.  But, a girl can dream.  Right?

So in order to feed my illusion, I thought I came up with a nifty way to store them.  Use hubs’ protein powder containers.

However, there is one problem.

Okay, one big problem.

Simply allowing the ground to dry on the countertop doesn’t work.

They mold inside the containers.

Green, brown, and smelly.

(Okay, gross, green, brown and smelly.)  So, all that hard work of drying them and putting them in the containers was for nothing. *Sheesh*

So now I dry them in the oven after I cook dinner.  I simply turn off the oven and let them sit there overnight on a cookie sheet.  Alternatively, I dry them outside during the summer.

Don’t let the oven cool to much before putting them into dry.  Do it right away.

Since then, not one moldy container has passed under my nose.

Watch my video below to show you what you should look for when you store your coffee grounds and tips on how to store them.

 Join the Conversation

Do you reuse your coffee grounds?   If so, how do you store the used coffee grounds?

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Comments

  7. 7

    Hi there! Just came across your site and wanted to share with you how I’m drying my coffee grounds 🙂
    I started letting them air dry inside the house (or outside when weather allows it) for a day or two…till they were very dry feeling. Then I dumped them into a 1/2 gallon mason jar I have. After dumping my first stash into the jar, I noticed the next morning there was some very light moisture inside the jar. All I did for the next few times was let the grounds sit out and dry even longer. This seemed to take care of the problem. For about a week, things looked just fine. I added another stash of coffee grounds after having them sitting out for a few days, but they ended up creating moisture. I am thinking this has something to do either with the weather (its been a lot colder lately) and/or with the fact that these grounds were whole beans that my mom ground up herself – a little too much – and are now basically a VERY FINE powder. Since I really don’t want to risk having to throw out the amount of coffee grounds I’ve collected to far, tonight I decided to bake them. I spread some out on a cookie sheet lined with parchment paper and baked them at 200 degrees F for 20-30 minutes. So far they are looking really nice. I can only put one cookie sheet in at a time so it will be a little while till I get them all baked. This time, though, I will go ahead and put them back in the 1/2 gallon mason jar, but like you also mentioned, I will be adding in a silica packet. I have Oxygen Absorbers. I use these packets for my food storage (I am a “prepper”) and so far they seem to work really well. I use my coffee grounds for compost in my worm bin, but also will be using them to make homemade body scrubs so I think the silica packets will be very helpful in keeping the grounds dry.

    Reply
  8. 9

    Ms Anna, I just wante to thank you & let you know that I have been searching for over 2-3 weeks on how to dry coffee grounds in the oven. I knew that it could be done but it just didn’t know on what degrees to put my oven without burning the grounds. I’ve seen from various YouTubers that with wet grounds, the grounds would only last one (1) week. Again, thank you so very much. You might think about putting this on the web because even there I could only find for drying large quantities outside for coffee farms!!

    Reply
  9. 11

    Hi! Was a bit confused about timing…. so, the coffee grounds go in the oven at 135 degrees, and then how long should they stay in the oven for?
    Thank you so much!!
    Chloe

    Reply
  10. 13

    How to store and utilize used coffee grounds
    PROBLEM:- Fresh used coffee grounds go mouldy within a week if not dried.

    VERY WET coffee grounds store for 2-3 weeks and NO MOULD.

    PLEASE don’t waist valuable energy = carbon dioxide = global warming,
    drying your coffee grounds its NOT ECO-FRIENDLY.
    Recycling that uses more energy than it saves is just d**b, oops, uninformed, :-).

    I have successful been storing my coffee grounds for a week or 3, by storing them IN WATER
    ( I go to my big garden most, but not every weekend).

    I live in an apartment, so I just drop the coffee grounds from my stove top percolator into an old 2 litre or 1/2gal yoghurt container on my kitchen window ledge (most convenient place). I start with it 1/2 full of water and the coffee grounds NEVER get mouldy as mould requires food, moisture and oxygen. By keeping them covered in water it excludes enough of the oxygen. I then add it to my compost bin as 1 unit GREEN then add 3 units BROWN (dried leaves, paper etc ). Sometimes I just add it to a hole in garden with compost and “worm tea” before planting a shrub or throw it on soil surface in an area I’m about to dig over for an new herb or veggie bed.

    I have been using a 3 level worm farm in my laundry room for 17 years (most convenient place as its just off the kitchen & this keeps its temp more even so worms work hard all year ) so all my veggie waste gets mixed in there and sometimes the wet coffee grounds if its winter and the weather is too shite to go to the big garden. If I think the worm farm is getting too acidic I pop air dried egg shells in the blender for a few seconds, let the dust settle and sprinkle on surface of WFarm. The “worm tea” keeps my little sunny balcony garden thriving (6′ Habanero chilli & paw paw=papaya trees, 3′ dwarf lime & rosemary and assorted herbs). I live in Sydney Australia 600m from beach 🙂 minimum winter temp 7C or 44F so no frosts.

    Dry coffee grounds can be very HYDROPHOBIC or difficult to wet and seriously effecting the ability of rain to penetrate if left on soil surface, so best to compost, bury or cover with mulch.

    If your soil becomes too acidic = low PH, then add ground egg shells (use a blender and dry shells as you get a better result due to the massively higher surface area and more even distribution than crushing ) = no need to buy lime.

    I have recently started using “worm tea” to cover the old coffee grounds instead of tap water as I think there could be some colonisation of the grounds with friendly bacteria from the “worm tea”.
    The thinking is that the bacteria will start consuming the grounds as a nutrient and energy supply and therefore help them breakdown in soils faster and perhaps reduce the tendency of Coffee grounds to be hydrophobic if they should dry out. At the least it will save me from carrying as much down to the big garden.

    Finding a simple eco-friendly method of drying used grounds would mean non gardening coffee drinking friends could add to our supply

    More thoughts on drying coffee grounds

    Because I & most friends use stove top coffee percolators or home barrister style machines (it’s the Italian influence here in Australia) We end up with compressed pellets of used coffee grounds. These pellets do not seem to contain as much water and no filter paper like as the filter/drip type.
    4x2cm or 1.5×3/4inch for the 1 cup
    5.5×2.5cm or 2.25x1inch for the 3 cup Sundays 

    These are easy to dry on a tray on top of the FRIDGE as it’s a nice warm dry area using waste heat and they are unlikely to be accidentally knocked over. So far the first small ones seem to be drying well and no mould the larger ones have not been there long enough as it’s Sunday today. I have a friend who dries her grounds like this but places them on absorbent/kitchen paper on her tray as she says the paper helps suck the moisture out of the grounds and it evaporates better. She found they went mouldy (during cold wet weather and high humidity) until she thought of putting the tray in the warm air on top of fridge. I’ve just tried to eliminate the paper towels as I think she gets most of her drying from the warm air.

    But a combination of the two might be required esp with wetter grounds

    Filter/drip coffee grounds could be more difficult to dry. Adding a new batch of wet grounds on top of old in a container adds moisture to the top and keeps the older grounds from drying out. I had problems with mould even with my pellets with the air circulating between them. That is why I adopted the tray on top of fridge. With loose wet grounds and filter paper keeping the grounds in small piles or even better in the filter cones would aid warm air circulation between them and therefore drying faster before the mould can colonise the piles. After they are dry they can then be put in a container for storage or transport or giving to friends with a garden

    To be more scientific you could weigh your first pile daily and see when it stopped loosing weight=moisture to get a ‘rule of thumb’ for their drying time (perhaps a different one for winter)

    Have fun experimenting

    Reply
      • 15

        In the comments above I mentioned where I live mainly as a reference to the gardening climate/temp range and that I’m 6 months out of phase with your seasons.

        Not all air has the same drying power and used coffee grounds (UCG) seem to be particularly difficult to dry in the home without using some form of energy.

        Jars of UCGs left in sun on my balcony just end up with moisture condensing on the non sunny side but not drying even after a few days and then getting green mould.

        However its humidity that effects our ability to properly dry coffee grounds.
        The warmer air on top of fridge has a higher moisture carrying capacity and will therefore carry more moisture from coffee grounds compared to just room air drying. Similar to drying in very very low oven but reusing ‘waist heat’. They still may require further drying in oven as its cooling down after other use. Keeping the new/wet piles away from those already partly dry helps. Think of muffin tray.

        I avoid all this fiddling around drying UCGs by keeping them covered in water. I use this ‘coffee water’ on garden as well as the grounds.

        The fact that green mould colonises UCGs so rapidly, is an indication that they are very nutritious & when mixed into soil or compost, they will provide a great substrate for soil fungi and bacteria = fertilise the soil biosphere.

        Here is a fun bit of science to entertain the kids (or expand our knowledge about additives in our processed food). Using a 1/4 cup container moisten this amount of bread (organic and supermarket), breakfast cereal, cookies etc and place them on a tray and observe over the next week or so.
        I predict that fungi will colonise the coffee first, and much slower, or never, in the ‘foods’ with more additives and fungicides in i.e. supermarket bread

        Isn’t it great UCG goes mouldy so quickly, as it hasn’t been messed with by big food companies.

        have fun

        Reply
      • 18

        Older style fridges used to reject all their heat at the back. But modern ones seem to also use the sides so use your hand to detect where the warmer parts are and put your tray on the top above that, but poking out over the edge so the warm air rising will hit your tray and warm it and dry your coffee grounds that are close to this warm part.
        You might have to experiment with the time.
        I mentioned above I have fairly compact pellets of coffee but if you have very wet grounds then it will take much longer (several days) if you put them on a few sheets of old newspaper they will help wick out the water and make it easier to tell if the paper is dry under the grounds then they are dry. This also speeds up the oven drying method as the low temp will not cause problems with the paper

        Also as mentioned by Anna spreading them out helps speed up both these drying processes = more surface area

        By the way the mould only ‘looks’ to be a problem but its just nature starting the breakdown of the grounds your compost heap and garden don’t mind. Mould on my pellets is only minor but wet filter coffe grounds seem to become smelly if not dried.

        If all this drying is too much then store them covered in water as I mentioned above

        Reply
  11. 19

    I have always been wondering what to do with my coffee grounds and these tips are just perfect and gives me endless ideas on how I will recycle them. I have a small garden which I believe will benefit from this. Thank you for the share.

    Cindy

    Reply
    • 21

      Bill, great idea. But I bet you can also just put the coffee grounds in a freezer bag is you want to store them in the freezer. What do you think? Anna

      Reply

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