"It was disgusting," he said. "I would find everything in that garbage, like wet bagels the size of an inner tube."
With parts from a clothes dryer he found on the street, Sprules built a 45-gallon (170-liter) dryer to dry the wet coffee. He then mixed in candle wax with the coffee grounds, added some animal feed binder, and used a car jack to compress the logs. It took him ten minutes to produce one log.
Friends and family were given sample logs. They were not impressed at first. "The logs were terrible," Sprules said. "People tried to light them and they wouldn't work."
But Sprules soon fixed the ignition problem, and the following season he began selling the Java-Log at the local farmers market, where the log became a word-of-mouth hit.
Today Sprules buys his grounds from an instant-coffee manufacturer. But he hopes to set up a recycling agreement with a coffeehouse chain.
His company, Robustion, makes the logs in an old government feed mill. The production capacity has certainly increased since the early days. "Now we make one per second," he said.
The Java-Log weighs 5 pounds (2.3 kilograms), and it's a little smaller than a sawdust log. It comes in a wrapper, which is used to light the log. It burns for two to three hours, the same as a regular log, but it produces three times the flame capacity of wood.
"That's because coffee has more oil than wood, while wood has a lot more char and carbon in it," Sprules said.
The smell is not what most people would expect, Sprules says. "It's not like a roastery. It doesn't smell that much. But it has a slight aroma, and most people seem to like it."
According to OMNI, an independent testing company in Beaverton, Oregon, the Java-Log burns seven times cleaner than firewood and emits 96 percent less residue. It produces 54 percent less carbon dioxide than sawdust fire logs.
The Java-Log also reduces waste headed for landfills. Each year the bulk of spent coffee grounds are sent directly to landfills. From there the rotting coffee grounds release carbon dioxide, a greenhouse gas, into the atmosphere.
Sprules estimates that 6,000 tons (5,440 metric tons) of coffee grounds are wasted each year in Ottawa alone. "I really want to collect all coffee grounds from North America," he said.
But coffee grounds are valuable not only to make fire logs. They can also serve as a beneficial additive to gardens and compost piles.
The Starbucks chain runs a Grounds for Your Garden program, in which stores offer complimentary bags of spent coffee grounds to customers, parks, schools, and nurseries.
"The program began as a grassroots initiative nine years ago by a team of store partners who received numerous requests for the organic waste from their regular customers," said Ben Packard, the Starbucks environmental-affairs director.
Sprules doesn't see himself as a typical environmentalist. "I'm not the type of person who is going to drive a stake in a tree [to stop timber cutting]," he said. "I'm a bit more of a realist than that."
"There's a notion that environmental products cost more and perform less," he added. "I wanted to change that. What we wanted to do was design a product that was at least equivalent or better than what was out there."
It seems to be working. This year the Java-Log, which sells for about U.S. $3.49, is going into several major retail chains across the United States. Its share of the 400-million-U.S.-dollar North American fire-log market is still tiny, however.
"To get an environmental product out, you want to be able to take away market share from other products," Sprules said. "If people are already consuming something and you replace it with something that's more environmental, that's a lot more achievable than changing personal behavior."
Sprules is already thinking about new ways to recycle waste products.
"Next time you take out your garbage, do a little rummaging," he said. "You'll be amazed at all the interesting things that you find."
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