What Ales You?

  • Mike Kuethe ’13 measures the rate of fermentation in his lab-brewed ale.
    Mike Kuethe ’13 measures the rate of fermentation in his lab-brewed ale.
December 07, 2012
By brewing his own ale, Mike Kuethe ’13 examines whether people in medieval Europe really made their water cleaner by turning it into an early form of beer.

You’d have to drink a lot of beer to actually time travel, probably so much the trip would definitely not be worth it, but Mike Kuethe ’13 does it without sipping a drop. A history major (with minors in anthropology and English) who’s specifically interested in early medieval European history, Kuethe is brewing his own ale to study just how well the fermentation process can purify water tainted with bacteria.  

“One assertion almost every historian makes is that beer was so important because the water was frequently contaminated,” says Kuethe. “My question was, how effective is the production of alcohol in purifying water?” Kuethe, from Severna Park, Md., conceived the idea in Professor William Schindler’s experimental archaeology class, in which students are encouraged to work with primitive technologies. One such technology is fermentation. It’s still used today, Keuthe says (yogurt and cheese, for instance), but “the way our food system is set up we’re not engaged in the process.” We just go the Acme, buy it, and eat it.

Kuethe wanted to find an early medieval ale recipe, then follow the entire process that someone would have done in, say, Wales in the 1500s. Starting from the ground up—literally—he wanted to grow his own grain, harvest it, steep it in a vat of water to let the grain sprout, then roast it in a fire pit or oven to dry it out, shell it, grind it, and ferment it. Right away, though, he learned something interesting: “There are almost no primary sources on what is done” after the grain is prepared. This would make sense in context; making ale was so common, everybody did it, so why would anyone need a written recipe?

The other issue he ran into was time. Ultimately, he brewed the ale using a malt extract and yeast, the first batch to confirm fermentation, then the second two together, one as a control and one to which he added a strain of E. coli bacteria. Then he waited. And watched. He measured fermentation rates using a hydrometer, as well as observing and counting the CO2 bubbles escaping an airlock mechanism at the bottles’ necks.

Final tests detected no bacteria present in the ale. “In theory, this indicates that fermentation is as effective as the historians claim for purifying unsanitary water,” Kuethe says. “For me, though, the value in the experiment was designing the procedure and seeing what challenges presented themselves. I would also like to look into the historical methods of brewing and be able to re-do the experiment with accurate recipes and techniques of the past.” 


Last modified on Feb. 9th, 2013 at 10:55am by .