Can You Reuse Coffee Grounds?

If you’re used to starting your day with a cup of coffee or two, you’ve likely noticed how quickly used coffee grounds start to accumulate—and you might have wondered whether you can put them to work again to brew another cup.

But while reusing coffee grounds to brew more coffee might seem like a good way to save money and reduce food waste, you probably want to avoid doing so. Brewing a second cup of coffee with coffee grounds that have already been used will result in a less flavorful, less potent cup of coffee.

“You typically do not want to make a second cup of coffee with grounds that have already been brewed once,” says Matt Foster, the general manager for Century Coffee Co. and owner of Sol Luna Coffee Whiskey. “This is largely because the pleasant flavors in coffee grounds are extracted in the first few minutes of brewing—or in less than a minute if you're making espresso. If you attempt to brew the used coffee grounds again, you will likely get an unpleasant cup that tastes weak and bitter. There simply isn't enough left in the coffee grounds for the water to pull from.”

That said, there are plenty of other fun ways to make the most of used coffee grounds.

Culinary Uses for Used Coffee Grounds

While you probably want to skip using spent coffee grounds to brew more coffee, there are other ways you can repurpose those grounds in cooking, baking, and making cocktails. Foster recommends using leftover coffee grounds to make a coffee saccharum (similar to oleo saccharum, a citrusy syrup used in cocktails) to add to espresso martinis or nonalcoholic drinks.

To make a coffee saccharum:

1. Combine equal parts used coffee grounds (freshly used or frozen), granulated sugar, and brewed drip coffee.
2. Mix thoroughly.
3. Strain through a paper filter (this will take a fair amount of time if the grounds are small).

Small amounts of finely ground coffee—typically just a tablespoon or two—are also a popular ingredient in baking, and can even sub in for espresso powder in a pinch. Try adding just a bit of ground coffee to fudgy brownies, chocolate cake, or chocolate chip cookies. Coffee also works wonders in many savory recipes. Used coffee grounds are often employed in barbecue rubs and seasonings, and you can also put them to work in our recipes for coffee-braised pot roast, coffee-crusted beef tenderloin, and coffee-rubbed salmon sandwiches.

Editor's Tip: Finely ground coffee works best for culinary applications. If your used coffee grounds are still quite coarse, try crushing them into a fine powder with a mortar and pestle.

Gardening Uses for Used Coffee Grounds

Outside of the culinary world, used coffee grounds are commonly composted and can be repurposed occasionally in gardening. “Used coffee grounds can be used for compost as part of the ‘green’ component since they are a source of nitrogen,” Foster says. “Small amounts of used coffee grounds can also be added directly to the soil for vegetables such as tomatoes, carrots, and potatoes or flowers like roses and daffodils.”

Cleaning Uses for Used Coffee Grounds

Coffee grounds can also be used in household cleaning—try using them to remove stubborn buildup on pots and pans, to deep-clean your oven racks and grill grates or to get scuffs out of wooden furniture and floors.

Next time you have leftover coffee grounds, don't throw them out! Put them to good use in recipes, your compost pile, or save your grounds for cleaning throughout your home.