Devices that continously track and measures the fermentation dynamics during production of beer, wine, cider, mead, hard kombucha and other alcoholic fermentations, are called fermentation monitors. These can be inline or non-invasive, respectively in direct contact with the liquid, and not in contact with the liquid.
There are several methods used to measure fermentation, including refractometers, sonic and ultrasonic methods, floating devices and other. In common they all provide a digital measure of the fermentation.
The most important parameter used in fermentation is the density of the liquid, which is measured in degrees Plato, Brix, Oechsle or Specific Gravity, depended on the the users needs and preferations.
Direct and indirect measurements
We differentiate between direct and indirect methods of measuring gravity in beer and other liquids. In direct methods the actual parameter the sensor is reading is proportional to the density of the liquid - f.ex a floating hydrometer. In indirect density measurement, the actual density is estimated from another measured parameter.
An example of an indirect measurement of specific gravity, is the Plaato Airlock which utilized the production of CO2 in a fermentation. Simply explained, yeast splits sugars in the wort into equal parts of CO2 and ethanol, hence if you know how much CO2 has exited the fermenter, you also know how much ethanol is left behind - and specific gravity can be estimated.
There are benefits with both methods. CO2-generation in beer eg. is actually directly proportional to the fermentation activity - hence the accuracy of this latter parameter will be a direct measurement, and can be very accurate.
You can read more about the Airlock and how it utilizes CO2-production here: https://plaato.io/products/plaato-airlock
Industrial fermentation monitoring
The needs in commercial production of fermented liquids is very different from small-scale hobby production. In Plaato we are these days shipping our first industrial scaled fermentation monitor system, which is an inline beverage analyzer, made of 100% stainless steel and with superior accuracy.
Read more and join the ongoing pilot here: https://plaato.io/pages/plaato-industrial
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