Beer in Space

A fizzy Coca-Cola droplet floats aboard the Space Shuttle in August 1985. In a weightless environment, bubbles of carbon dioxide ("carbonation") aren't buoyant, so they remain randomly distributed in the fluid. The result can be a foamy mess!

Kirsten Sterrett, a University of Colorado graduate student, first became interested in how beer would brew in space while working at the Coors Brewing Company. Having studied aerospace engineering as an undergraduate, she began to wonder: How would yeast that perform fermentation fare in orbital free fall? The answer would not only shed light on the possible making of space-beer, but also provide valuable information to pharmaceutical companies with a keen interest in the biology of orbiting microbes.

When she returned to CU-Boulder for her master's work, she chose the topic for her thesis. Her experiments were sponsored by Coors and flown on the shuttle with the help of BioServe.

"I always said I wouldn't do an experiment that I couldn't eat or drink in the end," she jokes.

"Actually, after the experiment was all done, I gave (the space-beer) a little taste." The sample was only about 1 ml, which wasn't really enough to savor, she says, "but why throw something like that away?"

Along with her taste test, Sterrett performed a protein analysis on the beer and the yeast, measured the beer's specific gravity (the force exerted on it by gravity per unit volume), and "repitched" the yeast by brewing subsequent batches of beer with it. By all of these measures, the space-beer appeared to be essentially the same as beer brewed on Earth.

The behaviour of the yeast was somewhat puzzling, though. The total cell count in space-borne samples was lower that of "control" samples brewed on the ground, and the percentage of live cells was also lower. One of the yeast's proteins also existed in greater amounts in the space-brew.