Coffee Grounds Can Be Turned Into Biofuel, Study Finds

You’ve sipped your last drop of coffee—but what if your leftover grounds could still power your drive to work? According to researchers at the University of Nevada, the answer might be yes. Their study reveals that spent coffee grounds, usually tossed without a second thought, can be converted into usable biodiesel to run diesel engines.

Yes, coffee grounds can be turned into biodiesel. Scientists estimate that global coffee waste could produce over 340 million gallons of biodiesel per year, with an average of around 15% oil content extracted from the grounds using solvents.

What the Study Found

Published in the December issue of the Journal of Agricultural and Food Chemistry, the research was led by Mano Misra, Narasimharao Kondamudi, and Susanta Mohapatra from the University of Nevada. While it’s long been known that coffee contains some oil, this team conducted the first detailed analysis specifically on used coffee grounds. They collected 50 pounds of spent grounds from several Starbucks locations, dried them in an oven, and then used chemical solvents to extract the oil.

How Much Oil Is Actually in Coffee Waste?

The extracted coffee oil made up approximately 15% of the weight of the dried grounds. That’s less than oils from soybeans, rapeseed, or palm, which are more commonly used for biodiesel. However, coffee oil offers advantages—it’s more chemically stable due to its higher antioxidant content. Researchers estimated that the process requires relatively low energy input, and the resulting biodiesel could be priced at around $1 per gallon.

Challenges to Scaling Up

One major hurdle is the difficulty of collecting enough used coffee grounds efficiently. While the team plans to launch a small pilot program in 2024, sourcing grounds directly from Starbucks locations to feed into a biodiesel plant, the potential output is limited. Even if all the coffee grounds in the world were used, the total biodiesel produced would still make up less than 1% of U.S. annual diesel consumption.

The researchers emphasized that while coffee-based biodiesel won’t replace fossil fuels entirely, it’s a meaningful step toward repurposing waste into usable energy. As Dr. Misra noted, “It may not solve the global energy crisis, but your morning coffee could help reduce environmental impact—and yes, your exhaust might even smell a bit like coffee.”

Frequently Asked Questions

How much biodiesel can be made from coffee grounds each year?

Researchers estimate that the global coffee waste stream—over 16 billion pounds annually—could yield more than 340 million gallons of biodiesel, based on an average oil content of 11% to 20% from the grounds.

What is the oil content of used coffee grounds?

On average, dried used coffee grounds contain around 15% oil by weight. This is lower than oils from crops like soy or rapeseed, but the coffee oil is more stable due to higher antioxidant levels.

How did the researchers extract oil from coffee grounds?

The team collected 50 pounds of used coffee grounds from Starbucks, dried them in an oven, and then used chemical solvents to extract the oil. The solvents used are reusable, and the leftover solids can be repurposed as fertilizer, ethanol feedstock, or fuel pellets.

Is coffee biodiesel production scalable?

Not yet. The main challenge is collecting enough used coffee grounds efficiently. The research team plans a small pilot system in 2024, but even if all global coffee waste were converted, it would supply less than 1% of U.S. diesel use.

What are the benefits of coffee-derived biodiesel?

Besides being a renewable fuel from waste, coffee biodiesel is more stable due to its antioxidant content. Additionally, vehicles running on it may emit a slight coffee aroma, and the process requires relatively low energy compared to other biofuels.

Can I make biodiesel from my home coffee grounds?

The study used a controlled chemical process with solvents and industrial-scale drying. While technically possible, home setups lack the precision and materials to safely or efficiently produce usable biodiesel from coffee grounds at this time.

Recommended FrontStreet Coffee Beans for Biodiesel Curious Brewers

If you’re curious about the broader coffee journey—from cup to combustion—try these FrontStreet offerings. The FrontStreet Classic Blend delivers balanced sweetness with notes of caramel and nuts, perfect for everyday brewing. For something fruitier, their Ethiopia Yirgacheffe showcases bright citrus and floral tones. And the Brazil Queen Manor brings smooth chocolate and nutty depth. All three highlight the versatility of coffee beyond the brew—and the potential even grounds hold. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.