GOLDEN, Colo. —  Beer and a tank of gas will usually get you on the road to nowhere. But chemical engineers who partnered with Coors Brewing Co. (search) have found a way to make it a fuel-efficient combination.

Though Coors and its partner, Merrick & Co., aren’t pouring brewskies straight into your car, they are turning some of the waste created during the beer-making process into 200-proof high-octane alcohol called ethanol (search), used to purify gasoline.

“We really never thought we were going to have something of ours go directly into your gas tank,” said Coors’ Rick Paine.

Some states mandate ethanol be blended with gasoline to reduce harmful emissions such as carbon monoxide (search). In the U.S., about 4 million cars on the road run on the purer form of gas, called E-85 (search).

“For every gallon of ethanol that we put into the gasoline pool, we get back out a gallon of crude oil that comes from who-knows-where,” said Steven Wagner of Merrick.

There are opponents to ethanol production, but their focus is more on the traditional way of extracting it — from corn. Critics point to studies showing that process is not cost-effective.

Click in the video box near the top of the story to watch a full report by FOX News' Alicia Acuna.