Home-brewed biodiesel may be ready to move from your neighbor's garage to prime time. No longer is the practice limited to a few mechanically inclined hippies with old converted electric water heaters. Now anyone can order up their own bio-brew kit online.

"We are testing some products now to make sure they work at the level of quality our customers expect," said Go Green Home Stores spokesman Dennis Healy. "We're really looking forward to having these products in our store."

And Go Green's interest in mass-marketing a processor comes on the heels of a decision earlier this year by Northern Tool, the Sears of professional-grade tools, to put biodiesel processors for home brewers in its catalog, for $3,000 to $13,500.

The Collective Biodiesel Project estimates that home brewers, who filter used vegetable oil from restaurants and then mix it with lye and methanol to create their own biodiesel, produced 450 million gallons of fuel last year. Some brewers say they got tired of waiting for alternatives to petroleum to come from big biz and set out to change their own habits.

In Europe, home-brewed biodiesel from both virgin and waste vegetable oil was so common that in 2002, police in Great Britain set up a "frying squad" to seek out and ticket chips-scented cars using the cheaper, tax-free cooking oil.

In the United States, a dozen or so niche manufacturers, such as Home Biodiesel Kits, already sell kits to home brewers who want to go beyond converting an old electric water heater. But the fact that home-brew equipment will be available at a major retail outlet rather than merely at niche sellers signals that companies believe there's demand and have faith in the safety and reliability of the equipment.

Biodiesel has two distinct faces. Big, young biodiesel companies are rising stars on angel-investor and venture-capital circles' lists of emerging alt-fuels. Their biodiesel tends to be what home brewers call virgin fuel – made from fresh, new vegetable oil. Most of it is sold to companies and agencies large enough to have their own fleets and pumps.

And there's also the flourishing underground of brewers. From neighbors running reactors in garages, like Jules Dervaes and Hans Huth, to a Piedmont, North Carolina, cooperative that has grown to 500 members in four years and made a million gallons last year, home brewing is well-established.

Dervaes and his family have turned their home in Pasadena, California, into a green "best practices" lab. They began brewing bio about four years ago, using an open source manual on how to build a converter from an old electric water heater.

Dervaes makes about 30 gallons once a month from restaurant waste oil he gets for free. His family has a standing relationship with neighborhood restaurants glad to be rid of grease they'd otherwise have to pay to have hauled away.

"It's a big win for everybody," Dervaes said. "We're off the [petroleum] oil grid, the [vegetable] oil is being used twice, and the fuel is being made locally, not hauled around the world."

Restaurant owners like Lucas Manteca of Cape May, New Jersey, are delighted to participate, even if there are a few problems. Manteca and his wife own three Quahog's Seafood Shacks and give away about three 55-gallon drums a week.

It's great," Manteca said. "Before this, we were paying for the oil pickup, and they were just destroying the oil."

"Restaurants are such a huge source of waste, a lot of trash and oil and water, but it can be difficult and expensive to try to do things the right way," he added. "This is just easy and right."

But with rising oil prices, waste oil has become a commodity. The New York Times reported in May that restaurants in at least 20 states have had oil stolen. Waste-management companies looking for an edge over their competition, opportunistic thieves and home brewers have all been caught with their hands in the grease barrel.

"There's a lot of talk about grease wars where people do nasty stuff to get the grease," said Leif Forer, one of the founding members of the Piedmont co-op. "The waste oil used to go to rendering companies that got paid to pick it up and then sold it 'back to the animals' for pet food and livestock feed. They're not happy with us."

The co-op started six years ago in a community college class taught by Forer and co-founder Rachel Burton. They made their first batch in Mason jars, and graduated to the kitchen blender.

"Eventually we designed and built our own processor. At the end of the day, the process and mechanics are the same as the Mason jar," he said. "Now we have two plants, and we can make biodiesel in a continuous stream."

The co-op currently makes more than 120,000 gallons a month, far more than its 500 members consume.

"We got tired of waiting for a corporate solution and found a short-term answer that makes sense on a local scale," Forer said. "We'll settle for that until better fuels and technologies come."

While there have been few problems with home brewing, last month a garage biodiesel experiment ended when a chemical blast blew the front off a home in Surprise, Arizona. After the explosion, the assistant fire chief worried aloud that home brewing might mean more explosions.

But Hans Huth, another biodiesel home brewer who posted a do-it-yourself guide in 2006, says home brewers haven't had many problems – fewer than with the commercial plants.

"Obviously, you have to be careful!" Huth said. "You are refining a fuel you intend to burn."

Besides instructions on how to build and run a processor, Huth's manual includes information on local regulations and permits.

"Good information will keep us safer," he said. "If we start causing problems, the regulators – and I work with regulators – will have to come in and tighten it up. As a community, that makes things difficult."

At his day job with the Arizona Department of Environmental Quality, Huth is helping solve an international grease problem: sewage spills in Nogales, Arizona, caused by sewers across the border in Mexico that are jammed by grease from restaurants. He's helping build a biodiesel converter in Mexico.

"It looks like we'll be able to use the facility to generate enough biodiesel to fuel the Rio Rico Fire District," Huth said. "Once you start doing this, it becomes insidious, and you find yourself looking around saying, 'Where else can we go to get biodiesel?'"

The growth of home brewing from a few garages to mainstream recognition has its problems. For one, Huth says diesel cars, once the bane of used car lots, are now much harder to find and are selling for more money.

Forer, who's just returned from a national conference of biodiesel brewers in Golden, Colorado, also sees the arrival on the big stage as both a blessing and a curse.

"We have a consulting business, and we teach classes, and we're selling a half million gallons a year so we can use the money for other green projects," Forer said. "But we're closing in on the point when demand exceeds supply, and that might mean trouble."