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6 Interesting Ways to Use Leftover Coffee Grounds

Medically reviewed by Martha Juco, MD · Aesthetics

Written by Jason Inocencio · Updated Jul 25, 2022

6 Interesting Ways to Use Leftover Coffee Grounds

The drinking of coffee often finds us enjoying the dark liquid as it enters our mouths. Although the satisfaction is often undeniable, we don’t really give a second thought to the coffee grounds left behind after the coffee is brewed. What most people do not know, however, is that those coffee grounds are still useful. After brewing, there are a lot of unknown coffee ground uses.

Spent coffee ground (SCG) contains large amounts of organic compounds (i.e. fatty acids, amino acids, polyphenols, minerals, and polysaccharides). Earlier innovation explored the extraction of specific components such as oil, flavor, terpenes, and alcohols as value-added products.

However, byproducts of coffee fruit and bean processing can also be considered as potential functional ingredients for the food industry. There is an urgent need for practical and innovative ideas to use this low-cost SCG. Its full potential has not been exploited to increase the overall sustainability of the coffee agro-industry.

6 Coffee Ground Uses You May Not Know About

Did you know that there are practical coffee ground uses around the home, even going so far as to useful in one’s garden and even for sprucing up one’s beauty routine?

Fertilize your garden

Coffee grounds make great fertilizer because they contain several key nutrients required for plant growth. SCG can also help attract worms and decrease the concentrations of heavy metals in the soil.

Compost it for later

Adding compost to one’s garden can significantly improve the health of your plants. Coffee grounds can help increase nutrient levels while decreasing the greenhouse gas emissions of one’s compost.

Repel insects and pests

Several compounds in SCG are toxic to many insects. It’s surprising to learn that coffee grounds can actually be used to repel mosquitos, fruit flies, beetles, and other pests.

Remove fleas from your pets

Like some of those previously mentioned insects, fleas do not like coffee. Keep your pet flea-free by bathing them in used coffee grounds.

Neutralize odors

Odors emanating from the refrigerator can be unpleasant but no need to worry. Coffee grounds can help absorb and eliminate odors from your refrigerator, gym bag, or even from smelly shoes. Using them as a hand scrub can also help remove lingering smells from onion or garlic.

Use it as a natural cleaning scrub

SCG can be used as an abrasive cleaner and can help sanitize and remove buildup from sinks, cookware, grills, and other surfaces around the house.

Coffee Ground Uses: Removing lead ions from water

In an attempt to reuse food waste for useful purposes, a study investigated the possibility of using coffee grounds to remove lead ions from drinking water. The lead ion adsorption characteristics of coffee beans and grounds were studied by measuring their fat and protein content, adsorption isotherms for lead ions, and adsorption rates for lead ions. The number of lead ions adsorbed by coffee grounds did not depend on the kind of coffee beans or the temperature at which adsorption tests were performed.

The rate of lead ion adsorption by coffee grounds was directly proportional to the amount of coffee grounds added to the solution. When coffee grounds were degreased or boiled, the number of lead ions decreased. The experiments demonstrated that proteins contained in coffee beans depend upon the adsorption of lead ion. In essence, this study demonstrated that the abundant food waste that is coffee grounds can indeed be used for removing lead ions from drinking water.

Coffee Ground Uses: Converting to biodiesel

Yet another study conducted with SCG attempted to extract oil from the grounds and then convert that same oil to biodiesel. Depending on whether it uses Arabica or Robusta coffee, this process yields 10-15% oil. The biodiesel derived from the coffee grounds (100% conversion of oil to biodiesel) was found to be stable for more than 1 month under ambient conditions.

It is projected that 340 million gallons of biodiesel can be produced from the waste coffee grounds around the world. In addition, the coffee grounds after oil extraction also proved to be ideal materials for garden fertilizer, feedstock for ethanol, and as fuel pellets.

Key takeaways

The world continues to learn new ways of recycling waste products. An unexpected bonus that most are likely unaware of might be in coffee ground uses. More uses are being found for something seemingly so ubiquitous as coffee grounds. It is heartening to learn how these can be reused for other purposes.

For more on healthy recipes and ingredients, click here.


Hello Health Group does not provide medical advice, diagnosis or treatment.

Medically reviewed by

Martha Juco, MD


Written by Jason Inocencio · Updated Jul 25, 2022

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