beer yeast

The Friday Mash (Income Tax Edition)

On this day in 1913, the Sixteenth Amendment, which authorized a federal income tax, was ratified by the states. That’s the bad news. The good news is that you’ll have an extra three days to file your federal return this year.

And now….The Mash!

We begin on the Moon, where beer might be brewed someday. Wort and beer yeast will be placed aboard a lunar lander to find out whether the yeasts stay viable under lunar conditions.

The latest must-have accessory is the Drink Tanks growler. It looks like a piece of industrial camping equipment, and can keep up to two gallons of beer fresh for 24 hours.

Now that on-demand streaming has replaced records, classic rock bands—along with a few newcomers—are turning to branded beer as a way of monetizing their intellectual property.

Boulevard Brewing Company has added American Kolsch to its core lineup, which also includes Unfiltered Wheat, Pale Ale, and KC Pils. It debuted this week at Kansas City-area establishments.

Scientists are exploring sensation transference, the phenomenon that explains why listening to a pleasant soundtrack causes you to perceive the beer you’re drinking as sweeter.

Richmond, Virginia-based Veil Brewing Company has released Hornswoggler with Oreos, a chocolate milk stout conditioned with hundreds of pounds of the famous cookies.

Finally, Guinness really might be good for you. Researchers have linked iron deficiency anemia and hearing loss, and Guinness is rich in iron. In addition, Guinness supposedly contains antioxidants and suppresses the accumulation of “bad” cholesterol.

Tracing Beer Yeasts’ “Family Tree”

Humans domesticated yeasts long before they figured that yeasts even existed. Now a team of geneticists created the first family tree of those yeasts. They did so by examining samples collected from nearly 100 breweries around the world.

For most of history, people made beer at home. Because beer kept for a long time, it was necessary to brew only once a month or so. The long interval gave the wild yeasts in the beer enough time to interbreed with other strains and stay feral. But with the rise of commercial brewing some 400 years ago, brewers made beer on a continuous basis. In an effort to make the beer consistent, they inadvertently changed the yeasts’ genetic makeup. Brewers “backslopped”—that is, they took the sediment at the end of the brewing process and used it to inoculate the next batch. Over time, the yeasts lost the ability to sexually reproduce and acquired genes that helped them digest maltose, a type of sugar found in backslop.

It turns out that brewing yeasts were domesticated in two separate lineages. “Beer 1” emerged in Germany and Belgium around the turn of the 17th century. Those yeasts spread to the United Kingdom and, from there, to North America. Most of the yeasts used in brewing today belong to the Beer 1 branch of the family tree.

About 50 years later, another branch of beer yeasts, “Beer 2,” arose independently. The geneticists who studied them are unable to identify their place of origin. Beer 2 yeasts evolved from yeasts found in wineries, and generally result in beers with higher alcohol content.

It is almost impossible to distinguish a Beer 1 yeast from a Beer 2 yeast based on flavor alone. Beer yeasts can create such a variety of flavors that even two closely related-yeasts can create beer with vastly different tastes.

Genetics and Beer Yeast

It’s a development that Nobel laureate Dr. Randy Schekman, a yeast geneticist at the University of California, Berkeley, calls “long overdue.” The brewing community is finally studying the molecular basis of differences in yeast strains. Researchers at California’s White Labs and at a Belgian laboratory are creating the first genetic “family tree” for brewing yeasts and the beers they make. They’ve sequenced the DNA—some 12 million molecules–of more than 240 yeast strains from around the world. Differences among those molecules translate into differences in flavor and aroma.

However, it may take time for this knowledge to be put to use making new and better yeast strains. Brewing yeasts are so specialized that cross-breeding rarely results in a strain that makes for good beer. And while genetic modification is possible–the Belgian team has several hundred such strains in storage—genetically-modified food carries such a stigma that brewers are unlikely to use them anytime soon. That said, the Belgian scientists hold out the possibility that with more comprehensive knowledge of yeast genetics, non-GM cross-breeding will become feasible.

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