Kvasny Prum. 2009; 55(4): 94-99 | DOI: 10.18832/kp2009009

Convenient Monitoring Of Brewery Fermentation Course By Refractometry.Peer-reviewed article

Jan ŠAVEL, Petr KOŠIN, Adam BROŽ, Karel SIGLER
1 Budějovický Budvar, n.p., Karolíny Světlé 4, 370 21 České Budějovice
2 Mikrobiologický ústav AVČR, 142 20 Praha

The course of wort fermentation is most often monitored by measuring density by immersion saccharometer or digital densitometer; other methods include classical analysis or automatic analyzers. Another possibility is the measurement of refraction in the course of fermentation. When the original refraction or wort extract is known, refraction unambiguously determines the apparent extract or degree of attenuation. A refractometer with a scale in Brix degrees can be used similarly as a saccharometer having a scale in mass percent of sucrose. In the range of 0-16 mass % sucrose and 0-8% ethanol refraction is a linear function of concentration; this allows us to calculate concentration of ethanol, real extract and also an apparent extract in the course of fermentation from the values of actual and original refraction. Examples are given of measurement and instrument calibration. The measurements can be done with simple and inexpensive refractometers with computing compensation of the effect of temperature.The course of wort fermentation is most often monitored by measuring density by immersion saccharometer or digital densitometer; other methods include classical analysis or automatic analyzers. Another possibility is the measurement of refraction in the course of fermentation. When the original refraction or wort extract is known, refraction unambiguously determines the apparent extract or degree of attenuation. A refractometer with a scale in Brix degrees can be used similarly as a saccharometer having a scale in mass percent of sucrose. In the range of 0-16 mass % sucrose and 0-8% ethanol refraction is a linear function of concentration; this allows us to calculate concentration of ethanol, real extract and also an apparent extract in the course of fermentation from the values of actual and original refraction. Examples are given of measurement and instrument calibration. The measurements can be done with simple and inexpensive refractometers with computing compensation of the effect of temperature.

Keywords: wort, fermentation, refractometry, extract

Published: April 1, 2009 

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