Are you just throwing away antioxidants every morning? If you’re a coffee drinker, probably so: Those grounds we so hastily discard are actually chock full of antioxidants, scientists say.
To which your first response might be: So what? It’s not like you’re going to eat or otherwise ingest that soggy mess left behind in coffee machine. There are “homespun uses” for spent coffee grounds, like fertilizing plants and repelling insects. But Maria-Paz de Peña and colleagues have higher hopes for human uses of used coffee grounds.
In a study published in the American Chemical Society’s Journal of Agricultural and Food Chemistry, the researchers explore why and how we might do that — as well as what type of coffee brewing leaves behind the best grounds.
They found that filter, plunger and espresso-type coffeemakers left more antioxidants in coffee grounds, while mocha coffeemakers left the least. Because filter and espresso coffeemakers are more common in homes and commercial kitchens, the authors report that most grounds are likely to be good sources of antioxidants and other useful substances.
The antioxidants could be extracted from these grounds and made into dietary supplements, while what’s left behind after extraction could still be used for fertilizer.
People drink millions of coffee worldwide each day, generating millions of tons of used grounds annually — most of which winds up in landfills. Until Peña’s team comes through on the coffee ground supplements, here are some other ways you can reuse spent coffee grounds:
- Top 10 household uses for spent coffee grounds
You can also use grounds to get weird smells off your hands, make hair shiny and exfoliate skin (via EcoSalon). And last but not least: You can put them in your stomach, getting all that antioxidant goodness for yourself! Here’s an explainer from SheKnows on using coffee grounds in rubs, sauces and marinades.