Many of us start our day with a cup or two of freshly brewed coffee. Once the pot is full, the grounds may make their way to the trash can. If throwing a filter full of used coffee dregs into the trash feels wasteful, it’s because it is. There are plenty of things they can still be used for. They are also biodegradable, so finding another purpose for them is far more environmentally friendly than wrapping them in plastic and sending them to a landfill.
But, according to Carta Coffee Merchants, what you shouldn’t do is use the grounds to make a second batch of coffee. While you can utilize the granules to make another pot, the end product won’t be anywhere near as good as the first serving. Most of the pleasant taste will have been extracted during the initial brew. What you’ll be left with is likely less flavorful or bitter and will contain less caffeine than the earlier pot you made. There is also a chance that bacteria will develop on the grounds if time has passed between the first and second brewing. While the hot water used in the process may kill the germs, there’s a chance the microbes will have produced toxins that near-boiling liquid won’t take care of, and you could still get sick — so you probably shouldn’t take the risk.
However, despite the grounds not being great for coffee anymore, they have many other uses you can consider.
1. Add them to a rub for tender steak
While their ability to produce a decent cup of joe may have diminished, old coffee grounds can still take a steak to the next level when used in a rub. Keeping them for this purpose has several benefits. No matter how you like your beef cooked, moisture is still important, and used coffee granules can help trap moisture in the cut, keeping it juicy and tender. Like red wine, coffee contains compounds known as tannins, so just as pairing a good wine with your meat can intensify its fatty flavors, a coffee rub will have a similar effect.
The benefits go beyond improving taste and texture — your steak will look better too. With a coffee-based rub, you’ll add a dark hue, making the appearance of the sear you put on the outside of the meat look more intense. So, if you’re having steak for dinner, put the grounds from that morning’s coffee to good use, and you should be able to get the most from your finished dish.
2. Make a natural bug fogger repellent
Barbecues are a summer staple and give you an opportunity to enjoy some great grilled meats, a few drinks, and some pleasant outdoor weather. Unfortunately, your garden-based banquet might be blighted by the arrival of certain unwelcome guests. Biting insects are one of the downsides of the warmer seasons, but there are several ways to stave them off. You can use chemical repellents, but those can be expensive and contain toxic compounds, so spraying them around food is a terrible idea. But the good news is coffee drinkers have a natural alternative. Just hold on to your used grounds, and you’ll have a regular supply of natural, cheap mosquito repellent.
According to Death Wish Coffee Co., the smoke and the smell produced by burning coffee dregs are enough to keep insects away from you and your guests. Since you’ll be burning them, you need to let the granules dry out first. Place them on a flat surface or in a bowl, then find a good spot outside, upwind from where you will be spending most of your time to maximize the scent’s coverage. Then, just burn the grounds as you would incense. A small amount of lighter fluid can help get the fire going, and a damp cloth covering can be used to make them smoke and smolder even longer. A few bay leaves can also be added to increase the repellent’s effectiveness.
3. Keep ants away from your crops and home
Raising your own crops and gardens can be a cheap way to get nutritious, healthy, organic fruits and vegetables. Recently, many people have started growing their own food and are literally reaping the rewards. But producing your own vegetables is a little bit more complicated than just poking some seeds into the ground and coming back at harvest time: One major challenge is pests. Certain insects can infest a crop and nibble away at it before you can eat some of it yourself. Pesticides are available, but since one of the benefits of homegrown produce is the avoidance of potentially harmful chemicals, this may not be the solution you’re looking for.
Luckily, there are natural alternatives, one of which involves letting ants live peacefully in your garden. These predatory insects help improve the soil and eat some bugs that can target your plants. However, they need to know where the boundaries are. Ants in your home and your pantry isn’t as desirable, but you can use some coffee grounds to keep them outside where they belong. PageOneCoffee points out that the used granules provide a harmless barrier that can keep them from certain areas while producing a smell that most species of the bug aren’t keen on. Simply put a wall or mound of the coffee across the area the ants are using to enter; this should help keep them out.
4. Improve your compost
Composting your used coffee grounds is an infinitely more eco-friendly disposal method than simply throwing them out to end up in a landfill. It also has another benefit: The granules make a great addition to any compost heap. They contain roughly 2% nitrogen, a key ingredient in many fertilizers. The dregs are also nearly neutral in pH, beneficial to soil structure, and may repel several common garden pests (via Oregon State University).
There are many ways you can use the used grounds to give your garden a boost. According to Oregon State University, you can add them to a traditional compost heap in equal quantities as leaves and freshly cut grass. You can throw them on a static compost pile, though you should also include some form of carbon. Dried leaves and paper both work well for this purpose; if you use a paper coffee filter, you already have a handy source with the used granules. Finally, you can sprinkle them directly over your flower bed or vegetable patch, then cover them with a layer of leaves or mulch.
5. Keep your skin clean and healthy
When it comes to all-around health, the skin is often overlooked. It’s your biggest organ and plays a vital role in protecting you from harmful rays and infection, so why not give something back? Coffee isn’t just great for giving you a boost in the morning. If you keep your used grounds handy, you can use them to make a simple but effective exfoliating coffee scrub.
The recipe can be scaled depending on your needs and available granules. According to The Adventure Bite, to make enough for a single shower, you’ll need to combine half a cup of used coffee grounds with a quarter cup of sugar and between three to five tablespoons of olive oil. The amount of oil you add can be adjusted to fit your preference: More will provide a greater moisturizing effect, but those whose skin is naturally oily should probably use less. You’ll know you have the correct amount once the grounds cling together when you lightly squeeze them.
While you can make the scrub fresh every day, you could also make a large batch and have plenty ready to go any time you jump in the shower. If you’re making it in bulk, make sure you keep it in an airtight container (via The Adventure Bite).
6. Enhance fish bait
If your fishing trip starts early, you might kick things off by brewing a pot of fresh coffee over the campfire. The hot drink will wake you up and help cut through the morning chill. After the beverage is prepared, you may be tempted to toss the grounds into the bushes before you clean the pot and get on with your trip. But don’t do that: You could be throwing away your chances of a successful fishing day.
According to Gone Outdoors, mixing your used coffee granules with your worm bait might help you get a bite. The dregs will make them more active, and that increased movement may be enough to catch a fish’s attention. Additionally, some anglers claim the coffee’s smell will attract certain fish, like bass and trout, to their boats. Certain fishing enthusiasts also claim you’ll get better results if you plan ahead; they tend to mix up some coffee grounds and soil in a container, then add their bait worms the night before. The worms will nestle into the combination and become deeply infused with the coffee’s scent and flavor.
7. Clean stubborn stains on pots and pans
Coffee grounds’ usefulness in the kitchen goes far beyond waking you up in the morning and adding flavor to steak rubs. You can also use them to great effect when doing the dishes. Dry granules’ hardness and coarse texture make them an ideal natural scourer for removing stubborn grease and baked-on food from cookware. Coffee dregs are a natural product, so you aren’t introducing any potentially harmful chemicals to your kitchen or the environment. Using them as part of your cleaning routine is simple: Simply sprinkle a few spoonfuls of used grounds into a dirty pot or pan and scrub as normal with a sponge or cloth.
However, while this method is an ideal way to clean stainless steel, you shouldn’t use it on all of your cookware. As the coffee granules clear dirt through abrasion, you shouldn’t use them with dishes that could end up scratched or damaged. This includes pans with a non-stick coating; the grounds may remove that coating and ruin the surface. If you are unsure about using coffee dregs to clean certain kitchenware, try a small amount on a hard-to-notice area to see how it responds. Staining may also be an issue, so you shouldn’t utilize this cleaning method on porous or lightly-colored cookware and surfaces.
8. Remove onion or garlic smells from your hands
Onions, garlic, and other aromatics can lend an excellent scent and flavor to foods. Most of the time, they are best when used fresh, which means preparing them on a cutting board or countertop. Unless you use gloves, the smell of these items will cling to your hands. While these scents may get your taste buds watering after they’ve been combined with other ingredients, alone, they tend to be very strong and quite off-putting. Luckily, odor removal is another area where coffee grounds can help you.
An onion or garlic smell will remain on your skin for a long time, especially if you do nothing. In fact, according to Beachbody on Demand, it takes the body a day or two to break down the compounds causing the smell. However, a thorough wash combined with a coffee bean or ground-based scrub will quickly remove the undesirable scent. First, rub the used granules between your hands and fingers. Make sure you thoroughly hit all the areas the onion and garlic have touched. Following the scrubbing, rinse the grounds off your hands with cold water, and then wash them as normal with soap. The odor should be gone.
9. Eliminate persistent odors in a room
Coffee’s odor-removing properties can be applied in a similar way to other deodorizing methods, such as the use of baking soda. Just brewing a pot of coffee can fill your kitchen with a strong, pleasant scent that will mask milder smells. You can also use the dried granules to eliminate specific odors, though fresh grounds are better for this purpose. According to Crazy Coffee Crave, coffee contains relatively high nitrogen content because of its caffeine. This enhances the carbon in the ground coffee and its ability to trap and absorb compounds like sulfur — a common cause of foul odors around the home.
As LifeHacker explains, coffee will sometimes do the trick where other methods like baking soda or a vinegar solution have failed. Just a tablespoon of the used granules is enough to make a huge impact in as little as an hour.
Coffee dregs still work as a deodorizer because most of the nitrogen and carbon content is still there. However, the grounds won’t be very effective while wet; thoroughly dry them out by heating them in a 250-degree oven on a baking sheet (via Crazy Coffee Crave). Make sure to check on the granules regularly.
10. Add some flavor to your homebrew
Coffee can enhance many beer styles, but they’re most commonly associated with varieties like stouts and porters. Sometimes the ingredients used, particularly darker malts and roasted barley, will naturally impart a coffee-like taste to the brew. This flavor can be enhanced or added to drinks where it doesn’t naturally occur through the use of used grounds. Brewing website Mr. Beer recommends adding coffee during the bottling process, which makes sense as adding it before fermentation could affect the brew in a few ways.
Exactly what type of coffee to use and how much to add is a matter of preference. Most purists would recommend freshly brewing something strong, like an espresso, and using a high-quality bean. However, if you have a beer already strong in taste, like an imperial stout, you may get away with reusing the grounds you made your morning coffee with. Some of the less desirable flavors a second brewing can produce will likely be masked by those of the beer and its alcohol content, while the "coffee" essence itself should still shine through.
One of the joys of homebrewing is experimentation, so play around until you either get the result you were looking for or an unexpected outcome that is even better. If you’ve never brewed before, getting started is easy – so why not give it a try and find a way to combine two of your favorite beverages?