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Green beer usually conjures images of St. Patrick's Day, but it has an entirely different meaning at the Alaskan Brewing Co.

The local brewery was ahead of the curve on greenhouse gas reduction when it installed a carbon dioxide reclamation system in 1998. It was the first and only craft brewery in the country to have done so until Sierra Nevada Brewing Co. followed suit in 2008. Now the company is studying the feasibility of using the spent grains from the brewing process to fuel the plant's boiler system, company co-founder Geoff Larson said.

The installation last year of another efficiency-boosting machine is what may make the biomass boiler possible. Normally, spent grains come out of the brewing process too moist to dry out and burn efficiently. Now a mash filter press literally squeezes more moisture out of the grains, leaving them far dryer than the traditional means of separating solids from the liquid bound for fermentation.

Alaskan Brewing's use of the mash press filter is another first among American craft brewers, Larson said. Over one year, the system is expected to save more than 1 million gallons of water, nearly 65,000 gallons of diesel fuel and nearly 363,000 pounds of malt while producing more beer, company spokeswoman Ashley Johnston said.

Meanwhile, carbon dioxide created during the fermentation process, which most brewers let escape into the atmosphere, is fed to a $400,000 reclamation system that purifies it for use in the bottling process.

Before bottling, carbon dioxide is used to purge the air out of kegs and bottles. The goal is to force out as much oxygen as possible because it spoils flavors and cuts the beer's shelf life.

"Oxygen pick-up is everywhere. It's an insidious devil," Larson said.

The recycled carbon dioxide still ends up in the atmosphere, but by reusing a byproduct of fermentation, the company eliminated the need to buy carbon dioxide along with the reliability issues related to shipping the gas to Juneau, Larson said. Also, industrial suppliers use fossil fuels to produce carbon dioxide, thereby releasing more greenhouse gases.

Most breweries don't use reclamation systems because industrially produced carbon dioxide is inexpensive, Larson said.

"Sometimes living in the land of plenty makes you wasteful," he said.

Larson said he doesn't plan to slap labels on beer bottles announcing the company's green streak. That would feel exploitative, he said. To Larson, improving the brewery's efficiency is more about closing a loop of inputs and outputs, and balancing an equation.

"To a chemist, that's classic," he said.