Brewery Biosensors.

Just stay clear of their claws. Fredlyfish4/CC BY-SA 4.0.

There are an endless number of decisions that a brewer can make about a beer recipe, but one ingredient—water—seems like it should be an afterthought. But even for the most basic, cheap beers, brewers pay a lot of attention to water chemistry. If it’s too alkaline, or full of minerals and other contaminants, it will impact the flavor of the final product. So they carefully test their water sources to make sure they’re good enough—and now one brewery in the Czech Republic has hired some tiny new employees to take over this task. They’re paid in food. Because they’re crayfish.


At the Protivin Brewery—brewers of the Platan family of beersReuters reports, they can show whether water pumped from a local natural source is safe to use. Five of the clawed arthropods have infrared sensors mounted on their backs that monitor their heart rates and movement. A portion of the water headed for the brew kettle is diverted to their tank, and if three or more of the crayfish have elevated heart rates, or start moving around a lot, a computer will tell brewers within three minutes that there’s a problem.

The brewery is working with scientists from the University of South Bohemia to develop this biosensor system, which they plan to continue upgrading. Cameras that can monitor the crayfishes’ hearts are a planned addition. The system remains experimental, so brewers still have to monitor water quality in a lab.

Anything in the name of a good beer! Via Atlas Obscura.


  1. robert79 says

    It’s not a new idea. I remember seeing a documentary years (decades?) ago how water filtration plants which got their drinking water from the Rhine river used a certain type of fish to test the water quality. The fish would usually swim against the stream, unless they sensed contaminants in the water, in which case they would reverse course and GTFO. The “sensor” was basically a glass tube with water flowing through it at the fish’s swimming speed. If the fish was there, the water was good, if it wasn’t, an alarm would sound.

  2. Dunc says

    Hmmm… As someone who’s done a fair bit of fairly serious homebrewing, this sounds like bullshit. Water (or rather, brewing liquor -- “water” is what you clean up with) isn’t a question of OK / not OK, it’s a question of the precise concentrations of half a dozen different ions, at the parts per million level. You need the numbers so you know what corrections to supply.

  3. blf says

    Dunc@2, Please do smaller logical leaps. I have no idea where you get the idea the biosensors are used to check / determine how the water will affect the beer. As the quote in the OP says, the crayfish are used to check that the water is safe, which is not at all the same thing.

    From Newsweek’s article, How Crayfish Helps Czech Beer Taste So Good (yes, the title is misleading):

    New York-based Chatham Brewery co-owner Tom Crowell tells Newsweek, “Water obviously is 95 percent of beer, so water quality is very important. For every gallon of beer produced you’re using about six gallons of water. So you need a really good supply.”

    If a brewer draws from ground or lake water, then contamination could be an issue, he explains, saying it sounds like Protivín is using untreated water, thus the need for crayfish.

    New technology like the crayfish water detectors make it easier to detect impurities. […]

  4. says

    Dunc, I live with a homebrewer/craft brewer. It’s not the same as a brewery, no matter the insane amount of gear, and I’m quite familiar with the craft. I don’t think this is bullshit at all -- water quality counts, in particular when you’re dealing with pollution.

  5. Raucous Indignation says

    Water quality is critical for brewing. One of the four classic ingredients of beer (water, barley, hops and yeast) is alive. Yeast is not particularly fastidious, but it is a living organism and needs exacting conditions to reproduce reliably, predictably and consistently. Differences is water quality will result is variations in yeast reproduction and therefore in beer quality. And, yes, I was both a chemist and home-brewer before becoming a cog in the wheels of Big Medicine.

  6. says

    Raucous Indignation:

    Water quality is critical for brewing.

    Agreed. I’ve noted it’s quite easy to discern water quality in Spruce and herbal brews in particular.

  7. says

    At uni during the course on brewery we had an excursion in the Pilsner Urquell brewery, home of most known and most iconic Czeh beer. The brewmaster was told us that there are many myths surrounding their water use -- that they only their own wells because the water is special in them etc. He said that the brewery has indeed wells, but they do not have enough output to supply them with enough water, so they have to use tap water. And that they tried a lot of things to make the tap water suitable for beer brewing and the best solution they found was to filter it through a pile of super old bricks.
    At the end of the exurscion we all got blind drunk on free beer, so we forgot everything we learned.

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