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."