A California brewery is turning to a DNA-based assay to gauge whether its IPAs are being contaminated with unwanted bacteria, The Verge reports.
Pediococcus and Lactobacillus add sourness to beer, a flavor brewers may want in sour beers, but not in hoppy IPAs. While brewers take steps to avoid contamination and can plate bacteria to see what's there, the Russian River Brewing Company is using a testing kit called BrewPal from Invisible Sentinel to identify more quickly whether DNA from problematic Pediococcus and Lactobacillus is around, The Verge says. It notes that other companies like Sigma-Aldrich and Pall offer similar testing tools.
The BrewPal test involves three steps, The Verge reports, in which beer is sampled and centrifuged, then after a buffer is added, the liquid portion undergoes PCR amplification, and that amplified DNA is applied to a pregnancy test-like device that, within three minutes, gives a readout indicating whether problematic bacteria are present and whether there's a little or a lot of them there.
"One of the reasons it's such a difficult problem is that it's so difficult to catch it, and to prevent it," says Adam Bartles, the director of brewing operations at Victory Brewing. "These [bacteria], once they start producing acid, there's no rectification — you can't neutralize the sourness." Victory, which produces about a 100 times more beer than Russian River, has been using BrewPal to complement its bacteria plating approach to testing beers, the Verge notes.
"All these companies are trying to solve the beer spoilage problem because it's the kind of thing that can keep beer customers, both old and new, from buying a beer again," it adds.