Be A Better Zymologist: Use A Fermometer

The Fermometer® is a liquid crystal display thermometer designed to monitor the temperature of the fermentation process without the sanitation concerns of immersion thermometers.  Proper fermentation temperatures keep off flavors away. It sports suggested ranges for the fermentation of both ales, lagers, Belgian ales and red and white wines.  Please follow the yeast manufactures recommendations for the correct fermentation temperature.  Be a better homebrewer or winemaker.


It’s is easy to use. Simply peel off the paper and attach to the outside of your fermenter with the self-adhesive backing.  It is best to stick it at mid-height on your fermenter to average out any stratifications in temperature that may occur once the fermentation slows down.  Be careful, once it’s on, it won't come off without damaging it.

Reading the temperature is straight forward.  If one crystal is highlighted in green, it is that temperature.  If two adjoining crystals are highlighted in blue and tan, it is the temperature in between.

The Fermometer™ is water resistant, not water proof.  While it can easily be rinsed or washed with traditional cleaning and sanitizing solutions, it should not to be immersed for extended time periods.  That includes using t-shirts as evaporative coolers.  Such exposure will result in water seeping between the laminate layers and permanently discoloring the crystals.  As with beer, keep your Fermometer out of direct sunlight.


People have often inquired about the accuracy of the Fermometer® and what it is measuring when placed on the outside of the fermenter in contact with ambient air.   It’s very close to measuring the temperature of the fluid in the fermenter.  In most normal fermentation situations, the fermometer is only off by about 0.0 - 0.5 degrees from the internal fermenting temperature.

fermometer on fermenter
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