Brewmasters Now Using DNA Techniques to Spot Bad Batches

Instead of waiting for bacteria to grow, a quick genetic test can identify problem brews

beer brewing
Brewers at work making beer Judith Haeusler/Corbis

The burgeoning craft beer scene includes some brews with weird ingredients. One has yeast harvested from the brewmaster’s beard, there’s ale with a sprinkling of crushed Moon rocks and even a one-off beer apparently containing dead whale from Iceland. While people can debate exactly which odd ingredients go too far (the whale beer was banned before it hit shelves), it's the unintentional additions that can truly ruin a beer. Bacteria such as Pediococcus and Lactobacillus in the wrong beer can sour entire batches before they are bottled.

Fortunately, beer makers are adding new tools to their centuries-old brewing arsenal in the form of DNA tests that can flag problems, reports Josh Lowensohn for The Verge. Lowensohn visited Russian River Brewing in California to see how brewers avoid such contamination. He writes:

One of the big reasons so much testing is done is that these bacteria can be found just about everywhere if you’re brewing beer. The microbes are naturally occurring in malted barley, and can thrive in the nooks and crannies of brewing equipment — from drain pipes and hoses, to foam that may not have been washed away.

Breweries put in place numerous safeguards to keep contamination from happening. Russian River is in a rather unique situation because, alongside its hoppy beers, it’s also brewing sour beers, which are steeped with Pediococcus and Lactobacillus to produce a flavorful, funky taste. Like a Kosher kitchen, the brewery keeps the equipment completely separated from one another, so things like hoses, kegs, and even lifts are labeled with red tapes or "funky" warnings. Workers who have been producing one of those sour beers will even go home, take a shower, and come back later with a new pair of clothes to avoid cross-contamination.

Until recently, breweries would sample their beer batches and streak them on a plate containing agar, where bacteria can grow. In an incubator the microbes in the sample would multiply until the colony could be seen and identified. But the whole process takes time. Once a problem bacteria is spotted, the point of contamination needs to be found and cleaned. Days can be lost in the fix. "Anything in the line that holds that up pushes everything off," Mike Guilford, who is in charge of Russian River’s quality control, told The Verge. "If you lose one turn, you’ll lose thousands and thousands of dollars."

The new tests, such as BrewPal from the Philidelphia-based Invisible Sentinel, can instead flag bits of DNA that identify those problem species of Pediococcusand Lactobacillus bacteria. Several other companies — Sigma-Aldrich with their HybriScan system and Pall Corporation with GeneDisc — also target specific types of microbes that spoil beer. Although the systems can cost a few thousand to tens of thousands of dollars, to breweries it’s worth it.

Perhaps as the tests grow more ubiquitous, beer aficionados won’t have to rely on the guides that detail how to politely refuse a brew that has gone bad. And industry insiders can stop fretting that a few unexperienced breweries might ruin the craft brew boom. Instead, whether the ale or porter is better can be more a matter of personal taste.

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