Coffee grounds can be used in many things, from garden fertilizer to skin scrubs, cleaning products and flea repellents.
Coffee grounds are the residue from the preparation of coffee. It is generally considered waste, but it can be useful. Coffee grounds can be obtained by making coffee at home or in cafes that give them away. Here are the many uses of coffee grounds in this article.
Unexpected uses of coffee grounds
Coffee is a beverage made from roasted coffee beans. Coffee beans grow in about 80 countries in Central and South America, the Caribbean, Africa and Asia, and people around the world consume this beverage. According to the International Coffee Organization, people consumed more than 166,000 bags of coffee (weighing 60 kilograms [kg] each) in the world in 2020-2021.
1 Skin exfoliation product
Coffee grounds can be mixed with water, honey or coconut oil to create a skin exfoliation product that can be used all over the body. Exfoliation removes dead cells from the top layer of skin and can unclog pores, clean skin and reduce acne. It can also make skin look brighter and reduce the appearance of fine lines.
A 2013 study suggests that caffeic acid, an antioxidant found in coffee, may reduce premature aging of cells and boost collagen levels.
2 Natural coloring
Coffee has a strong color, and coffee grounds can dye natural fabrics various shades of tan and brown. A 2019 study found that coffee grounds are a potential natural dye for use on a commercial scale because the fabrics the researchers dyed in the study remained colorfast by industry standards. People can also use coffee grounds to dye their hair, although they may not produce a significant color change or last long. That said, they may be fine for a short-term change.
3 Fertilizer for plants
Plants need nitrogen, phosphorus, potassium, calcium, magnesium and sulfur to grow. Coffee grounds can retain the nitrogen content of the soil, which can benefit plant growth. A 2019 study found that mixing coffee grounds into the soil improved the nutritional value of lettuce.
4 Insect, mosquito and flea repellent
Coffee contains diterpenes, which are toxic to insects. This can make coffee grounds a suitable insect repellent for someone’s garden. A 2018 study concluded that although coffee grounds are not toxic to ants, they are an effective repellent against them. Coffee can also be an effective method of mosquito control, as a 2015 study found that mosquitoes were less likely to hatch if coffee was present in their environment.
Fleas also don’t like coffee grounds. For this reason, one might try rubbing coffee grounds into his pet’s fur if he has fleas. However, before doing so, a veterinarian should be consulted to ensure that this method of flea prevention is suitable for the animal. Caffeine is toxic to cats and dogs, so be careful not to let your pet eat coffee grounds. Caffeine poisoning can cause symptoms in about 30 minutes and be fatal.
5 Cleaning product
Coffee grounds are a coarse powder. This means that it is abrasive and can be used to clean surfaces, utensils or appliances that have embedded or hard-to-remove dirt. That said, coffee grounds may be too rough to use on delicate surfaces or utensils.
6 Odor Relief
The caffeine in charred coffee grounds can eliminate odors by absorbing hydrogen sulfide molecules from the air. Therefore, coffee grounds can be turned into soap to neutralize odors on hands after cooking, for example, or to minimize odors in shoes.
7 Meat Tenderizer
Meat tenderizers use enzymes to break down fibers in meat to make it more tender and easier to eat. Meat tenderizer powders use acids and enzymes from fruits such as pineapple and papaya. Coffee grounds are acidic and contain enzymes that can also break down fibers in meat. We can therefore try to use the coffee grounds to tenderize the meat before cooking it. One can also marinate meat in coffee or use coffee grounds as a meat rub to add flavor.
8 Furniture restoration product
The strong coffee color can also be used to restore scratched wooden furniture. After mixing coffee grounds with water, the resulting paste can be rubbed into the scratches of wooden furniture to match the original color.
Cervera-Mata, A., et al. (2019). Spent coffee grounds improve the nutritional value in elements of lettuce (Lactuca sativa L.) and are an ecological alternative to inorganic fertilizers [Abstract].
Franca, AS, et al. (2009). Coffee processing solid wastes: Current uses and future perspectives.
Hardgrove, SJ, et al. (2016). Applying spent coffee grounds directly to urban agriculture soils greatly reduces plant growth [Abstract].
Herman, A., et al. (2013). Caffeine’s mechanisms of action and its cosmetic use [Abstract].
Kante, K., et al. (2012). Spent coffee-based activated carbon: Specific surface features and their importance for H2S separation process [Abstract].
Nam, C., et al. (2019). Natural dyeing application of used coffee grounds as a potential resource [Abstract].
Tsou, S.-H., et al. (2019). Potential oral health care agent from coffee against virulence factor of periodontitis.