Introducing our new DIY beer contamination test kit! Ever wondered if your beer, wort, or yeast slurry is contaminated? Now there is an easy way to find out if you just need a YES/NO answer. The detection media changes color from orange to yellow if contaminated due to a pH indicator. The majority of beer spoilers will be caught with this kit, including lactic acid bacteria, acetic acid bacteria, certain acid-producing wild yeast such as Brettanomyces, and other more obscure bacteria. These spoilers will lower the pH beyond the threshold needed to change the color of the media, but normal brewer’s yeast (Saccharomyces cerevisiae) will not. Everything you need for testing is included in the kit and it’s priced to sell.
Here’s how it works. Simply add a small volume of beer, wort, or water to a test tube with detection media and incubate at 28C (~82F) for up to a week (10 days at room temperature, or longer if you desire). You can also swab a surface or your yeast slurry and add it to the media. Compare the color of the tube with your sample with a reference tube without any sample to visualize the results. There’s no fancy incubation required and no mess. Here’s our more detailed instructions that come with the kit:
Our test results below show that after a one week incubation without shaking in aerobic conditions at 28C (~82F) the wild yeast Brettanomyces and lactic acid bacterium Lactobacillus are detected using only 10 cells, while Pediococcus (another lactic acid bacterium) is detected at 1000 cells due to its slower growth rate (however a longer incubation time did eventually result in a yellow tube at 10 cells and we regrettably don’t have a photo of this). It should be noted that another type of media can detect Pediococcus a little better than this particular type and this will be released as a professional contamination kit at a later date. Other bacteria that can be detected with this media include acetic acid bacteria Acetobacter and Gluconobacter, along with strict anaerobes Pectinatus and Megasphaera if grown under anaerobic conditions. Also it should be noted that Lactobacillus and Pediococcus can grow in both aerobic and anaerobic conditions.
Variables that influence the results include time, temperature, species, and cell count. The more cells you have of a particular beer spoiler, the faster the tube will turn yellow. Likewise, higher temperatures up to a point will result in faster results. If you want to know the identity of the beer spoiler you can always send us a sample for a species ID test. Please contact us for questions or comments since we always seek feedback to improve our methods.