You have probably heard of green buildings, green cars and, perhaps, even green phones. But were you aware that green beer is flowing from the taps of some U.S. breweries, and not the kind for St. Patrick's Day tomorrow? Among the leaders of the movement is Lucky Labrador Brewing Company in Portland, Ore., which for the past year has been saving big bucks by using solar energy to heat water used in the brewing process. 

Lucky Labrador's first green beer, "Solar Flare Ale," was an instant sensation when it was introduced in February 2008, according to brewery co-owner Gary Geist. Sales spiked in the month following the beer's debut, Geist says. But, he notes that going solar is more about long-term benefits than about temporary sales spurts.

He says the entire system, which includes 16 solar panels on the brewery roof, cost about $70,000 up front but that it ended up costing only about $6,000, thanks to a $21,000 (30 percent) federal tax credit, a $35,000 (50 percent) state tax credit, and an $8,000 incentive from the Energy Trust of Oregon (a nonprofit that assists businesses taking steps to reduce their gas and electrical energy consumption). It was quite the investment, he says, given that it saves the company about $3,000 annually in gas bills, which means it will have paid for itself by this time next year.

To understand how the sun powers Lucky Lab's beer-making operation, you must first understand how the beer is brewed. There are three stages to brewing, and two of them require very hot water, Geist explains. The first is to mix barley with water that's about 160 degrees Fahrenheit (71 degrees Celsius) in a nine-foot- (2.7-meter-) tall steel tank called the "mash tun" (the traditional term for barrel). When combined with hot water, the enzymes in the barley convert its starch into sugars.

Using a large fiberglass paddle, a brewer stirs the mixture, which Geist says looks like "cereal in water." After about an hour and a half, the sugary liquid, now called "wort," is separated from the barley with a sieve and transferred into a kettle, where it is boiled, along with hops—plants containing oils that give beer its bitter aroma and flavor. Finally, the wort is removed from the kettle, cooled, and then poured into a closed tank called a fermenter where it is combined with yeast, microbes that convert the sugars to alcohol and carbon dioxide.

The solar power drives the first step of the brewing process when the barley is mixed with hot water, says Bruce McLeod, lead installer for Ra Energy, the company that provided Lucky Lab with its system. Water entering the mash tun gets its heat from 16 four-by-10-foot (1.2-by-3-meter) "solar thermal collectors," thick panels atop the brewery's roof. As the panels absorb heat from the sun, a liquid made of propylene glycol and water that resists freezing during Oregon's cold winters within them becomes scorching hot (up to 230 degrees F, or 110 degrees C), McLeod explains. This broiling liquid passes through pipes into a heat exchanger, which transfers the heat energy to water stored in a massive 1,500-gallon (5,680-liter) tank in the brewery. This storage tank supplies hot water not only for the brewing process but for the kitchen and bathroom sinks, too, according to Geist. 

He notes that the system works like a hybrid car, meaning it gets its energy to heat water from two sources: solar energy, used in the mash tun phase, and natural gas, which is necessary for the kettle phase. The reason the sun cannot drive the whole process, he says, is because the solar system cannot heat water beyond 180 degrees F (82 degrees C), which is shy of the 212 degrees F (100 degrees C) needed to make it boil.

For this reason, Lucky Labrador cannot go 100 percent green—though it gets kudos from enviros for reducing its natural gas consumption by about 25 percent in the past year.

Does the beer taste any different? Not a bit, Geist says, noting he has no regrets about his decision to brew green. 

"We discovered that going solar was not only good for sustainability," he says, "but a good business decision with a great investment return."