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Scientists have discovered a new purpose for your leftover coffee grounds

Don't throw out your coffee grounds just yet

By Emily Caldwell Jan 1, 2025 7:33 AM

Coffee grounds — Caio / Pexels

Many coffee drinkers find unique ways to repurpose leftover coffee grounds, such as to enhance the nutrients in the soil of houseplants. But recently, Australian scientists have discovered another interesting purpose for your leftover coffee grounds. Researchers found that concrete can be made up to 30% stronger by adding charred coffee grounds to the mix. This interesting discovery could be the first of many ways to solve environmental challenges related to coffee waste and sand extraction.

Researchers from the Royal Melbourne Institute of Technology (RMIT) explain: “The disposal of organic waste poses an environmental challenge as it emits large amounts of greenhouse gases, including methane and carbon dioxide, which contribute to climate change.” RMIT University engineer Rajeev Roychand warns that “the world produces a staggering 10 billion kilograms (22 billion pounds) of coffee waste globally each year.” The problem is that most coffee waste ends up in landfills instead of being repurposed for other useful purposes, such as the one in this unique discovery.

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RMIT engineer Jie Li also weighs in, noting that “there are critical and long-lasting challenges in maintaining a sustainable supply of sand due to the finite nature of resources and the environmental impacts of sand mining. With a circular-economy approach, we could keep organic waste out of landfills and also better preserve our natural resources like sand.” Researchers do caution that this discovery is in its early stages, and additional research is still needed to assess the “long-term durability of their cement product” with added coffee grounds.

Emily is a Features Writer at The Manual, where she specializes in food, beverage, and travel content. She focuses on weaving… Read Full Bio

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Coffee & Tea

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