Reduce waste.  Create energy.  Cut costs.  And finally, make beer.

Purpose Energy converts brewery waste (leftover hops, barley, and yeast) using an anaerobic methane digester into biogas used to process the brewery's wastewater.

The Magic Hat Brewery in Burlington, Vermont was the first brewery to invest in PurposeEnergy's "Biphase Orbicular Biodigester" which began operations in June 2010.

Very cool.  Cheers!

Read an article describing the process in more detail here.