January 14, 2019

What Are Coffee Grounds Good For?

You get your press ready, grind up your beans, heat up your water, and finally enjoy a well-made cup of coffee. But what then? Truth is, most people end up simply throwing out their grounds after every pot of freshly-made coffee, either straight into the trash, or down the drain. But there’s more to coffee grounds than just making coffee. If you’re trying to minimize your daily waste and impact on the environment – or if you just want to be a little thriftier and make use of things that deserve better than to be thrown away and wasted – then you’ll find that there’s quite a lot, you can accomplish with used coffee grounds.

Coffee grounds are great abrasives, often contain enough leftover caffeine to be a deterrent to a range of animals and insects, and they have a number of ingenious and surprising uses, even long after you’ve already used them for their delicious coffee essence. But don’t be fooled! You cannot reuse coffee grounds for another cup of fresh coffee. Coffee beans are, unlike many teas and some herbal infusions, a single-use product when it comes to making beverages. Only about a third of the bean is soluble in water, with the rest being cellulose and other insoluble materials. Most of that third is extracted after a single brew, and all you’re left with after is a very bitter, almost burnt or ashy taste, with no body or flavor to speak of. However, coffee grounds have a number of properties that make them excellent in gardening, cosmetics, cleaning, and more.

Natural Deodorant

The first of many surprising uses for coffee grounds is for odor removal. However, it is neither as effective as you might think, nor should it be used in the capacity you might expect it to be used. Coffee grounds do not remove odors – they simply overpower them and allow you to add a better fragrance to an area that might previously have been contaminated with some form of rotting matter, or a particularly powerful stench. Coffee grounds also continue to emanate a strong smell after they’ve been used for upwards of a week, even in the outdoors, making them the perfect repellant for wild animals and pets that might try to eat your plants.

When compared to baking soda and activated charcoal, coffee makes for a poor deodorant. But it does produce a more pleasant smell, making it an effective way to not only combat certain odors, but quickly improve the smell of a room or cabinet. I wouldn’t stuff coffee grounds into my shoes as you might with baking soda but used coffee grounds are excellent in the bottom of a garbage bin (under the garbage bag), or inside a refrigerator.

If you ever purchase coffee you end up disliking heavily, don’t just throw it away. Grind it and use it as an aromatic. Unbrewed coffee is much more potent in both smell and longevity and is much more successful at warding off animals and keeping fridges nice and fragrant. After deciding you don’t want a certain batch of beans, keep them frozen, ground up a few fistfuls, and distribute the grounds in pots, and keep them in little bowls in fridges and cabinets.

Pest Repellant

As I’ve mentioned previously, coffee grounds make for an excellent pest repellant. Insects and small animals alike generally dislike caffeine and the scent of roasted coffee and will be warded off by it. If you have a small pet – a toy breed dog, a small rabbit, a hamster, or a cat – DO NOT leave coffee grounds lying around. While larger dogs can ingest some coffee and will generally stay away from it (they tend to heavily dislike bitter, sour foods), caffeine can and will kill smaller animals. It takes roughly 200mg per kg of bodyweight to induce severe caffeine toxicity in a dog, and similar amounts in other animals.

If your pet is pretty indiscriminate about what they eat – and some dogs certainly are – definitely do not keep coffee beans or grounds lying around anywhere within reach. If you notice a pet may have ingested caffeine, take them to the vet immediately.

If you don’t have any pets, however, caffeine is a safe way to keep animals away from your plants. The strong smell is usually enough to ward them off. Caffeine is also an effective pest control for snails and slugs, for whom the stuff is toxic. Mix it into your soil if you have a slug problem. The coffee grounds themselves also make for an excellent fertilizer.  

Exfoliant

Humans have been exfoliating for millennia, as the natural inclination to remove dirt and dead skin usually involves scraping it off with a porous rock, a fistful of sand, or, within modern contexts, a specially-formulated exfoliant (or skin scrub). But rather than spend an exorbitant amount on yet another skin product, why not give coffee a try? You can use the used grounds with some water or use a dash of virgin olive or coconut oil and scrub yourself clean.

Not only are you going to be removing any and all dead skin in the process, but some attest to the idea that smearing coffee on cellulite spots helps remove them. The science on this definitely isn’t clear, and the research is highly lacking, but the residual caffeine in your coffee grounds may in fact help tighten your skin a little bit. Either way, it smells good and helps you get a thorough clean.

Coffee Soap

Speaking of cleaning, if you’re looking for something more effective at giving yourself a wholesale body wash than just some grounds with a touch of oil, consider making your very own coffee soap. Also known as gardener’s soap, this is basically an extremely simple home-made soap you can fashion all on your own with just a few ingredients and a good deal of time. To get started, all you’re going to need is a soap mold, a series of oils, some brewed coffee, ground coffee, water, and lye. A more detailed recipe can be found here.

Fertilizer

Used coffee grounds are great as fertilizer, if you know how to use them. Simply mix them into your soil (yes, mix, not just throw them onto your plants) to add to the organic content level in your soil, which promotes aeration and attracts earthworms. Used coffee grounds very slowly release nitrogen into the soil as well, acting as a fertilizer, and they’re also effective for certain forms of pest control (like snails and slugs) as mentioned previously.

Because they’re acidic, coffee grounds are best mixed into soil used for acid-loving plants. But that’s only true if you’re using fresh coffee grounds that you simply don’t like using for coffee. Used coffee grounds are neutral, and not as effective – but still make for a great addition to any soil.

If you’re looking for an alternative use for coffee grounds in gardening, consider composing coffee alongside any other plant material or vegetable waste that you may have access to.

Remove Marks on Wood

A fairly simple trick that also works with a number of oily nuts like walnut and cashew, just mix a little virgin olive oil with some coffee grounds and wait for a few hours. Dip a cotton ball into the oil suffused with coffee, and rub the oily solution on any scuff marks, scratches, or cuts.

This is especially helpful if you have wooden floors or furniture scratched by a pet, like a dog, or if you’ve made some marks and indentations in a wooden desk. Simply gently rub the coffee oil over the mark until it’s uniform in color with the rest of the wood.

Cook with Your Grounds

Finally, consider playing around with your coffee grounds in other food items. You’d be surprised but used coffee grounds lend themselves excellently in any kind of meat rub (for lamb, poultry, beef and pork alike), a number of different cookie recipes, as well as cakes, brownies, and muffins. There are recipes all over to give you a better idea of how much you should be using when making batter or preparing a rub or some vegetable seasoning.

For anyone who loves coffee, the scent of coffee makes almost anything better. But, enough is enough. Even if you don’t end up preparing your signature chicken dishes with a thick rub of dried garlic, onion, pepper and coffee, and even if you don’t have much use for coffee grounds as a fertilizer, any one of these usage tips may come in handy now or later down the road. Just remember not to throw your grounds away just yet – collect and keep them! Used coffee grounds do go bad eventually, and they’re likely to mold or ferment if not dried, kept cool, or kept out in the open. If your coffee grounds stop smelling like coffee, get rid of them.