Coffee Logs Burned Out: How a Circular Economy Success Story Failed

A British startup spent a decade turning millions of cups of coffee into something useful: fire logs that burned in living room stoves, keeping waste out of landfills. The company was called bio-bean, founded in London in 2013, and the logic behind it was clean and satisfying. Used grounds from cafés, offices, restaurants, and transport hubs across the UK were collected, dried, and pressed into blocks. Each log contained the grounds from about 25 cups of coffee. A bag of 16 logs represented roughly 400 cups of waste diverted from the bin.

The environmental case was straightforward. Half a million tonnes of wet coffee grounds end up in UK landfills each year, where they rot and release methane—a greenhouse gas far more potent than carbon dioxide in the short term. Bio-bean's process, the company claimed, cut greenhouse-gas emissions by around 80% compared with sending grounds to landfill. That figure came from the company itself, not from independent verification, so it deserves to be read as bio-bean's own accounting rather than settled scientific fact. But the basic reasoning held: divert the waste, dry it, compress it, and you have a fuel that would otherwise have been a source of methane.

The marketing pitch, however, went further. Bio-bean sold the logs as burning 20% hotter than kiln-dried wood, and some retailers amplified the claim, adding that they burned longer too. The reasoning was sound enough: coffee contains a lot of energy, and once dried the logs held very little moisture. One tester who measured a batch found them at around 10% moisture, which sits between seasoned and kiln-dried firewood. Dry fuel does burn cleaner and hotter than damp fuel. But whether low moisture translated to the specific 20% performance edge on the packet was another question entirely.

When people actually put the logs in real stoves, the results were gentler than the label promised. Ignite Stoves & Fireplaces, perhaps the most careful tester, ran the logs in a showroom stove and reported that they felt roughly the same temperature as kiln-dried wood burned on the same air control settings. Not hotter. Roughly the same. On burn time, the same team found the logs not quite as long-lasting as kiln-dried logs, though they fairly noted that the kiln-dried log they tested was bigger than the two coffee logs it was beaten against. Lekto, another fuel supplier, put a single coffee log's burn at just an hour, roughly an hour less than kiln-dried oak. One reviewer said the logs mostly lived up to the claim in their experience, so it wasn't pure fantasy. But "mostly, in our experience" is a long way from a guaranteed 20%.

None of this erased the recycling case. A fuel made from waste that burns about as well as the wood it replaces is still a good outcome. The environmental logic doesn't depend on the log being hotter than a tree. It depends on the grounds not rotting in a tip, and the fire being fed by something already used once. On that measure the product held up whatever the marketing said.

But there was a practical problem with buying Coffee Logs by 2023: the company that made them no longer existed. In late March 2023, a fire at bio-bean's recycling plant in Cambridgeshire damaged vital machinery and scuppered investment plans. The fire wasn't the whole story. The firm had never turned a profit, and high energy costs were eating into what little margin existed. The business was forced into administration. Around 30 staff lost their jobs. A decade-long experiment in circular economy—one that actually worked, that actually diverted waste and created a usable product—ended not because the idea was wrong, but because the economics couldn't sustain it.