Beer Fermentation Control Using Ion Mobility Spectrometry – Results of a Pilot Study
Wolfgang Vautz1,3, Jörg Ingo Baumbach1 and Johannes Jung2
1 ISAS – Institute for Analytical Sciences, Bunsen-Kirchhoff-Straße 11, 44139 Dortmund, Germany.
2 Radeberger Gruppe c/o Dortmunder Actien-Brauerei AG (DAB), Steigerstraße 20, 44145 Dortmund, Germany.
3 Corresponding author. E-mail: vautz@ansci.de
J. Inst. Brew. 112(2), 157–164, 2006 | VIEW ARTICLE
ABSTRACT
Beer fermentation – a time consuming part of the production process – is typically terminated based on the degradation of diacetyl and 2,3-pentanedione below the odour threshold. Presently no on-line control of both analytes is available. As a consequence, fermentation is often carried out longer than necessary, thus decreasing productivity. In this pilot study, an ion mobility spectrometer using a UV-lamp as an ionisation source and a GC column (30°C constant) for pre-separation were used for the rapid determination of both analytes from the headspace of beer wort, during and after fermentation. Samples were heated to 60°C. Results from such analyses were available after a few minutes without further sample treatment or pre-concentration. Detection limits were below the odour threshold (ng/L range in the gas phase corresponding to the µg/L range in the liquid phase). Results were validated by comparison with the brewery’s standard GC-MS method. When applied on-line and in-situ, as a routine test in a brewery, it will help to ensure low levels of di-acetyl and 2,3-pentanedione in the product on the one hand and will increase productivity by saving time during fermentation on the other (up to one day in large breweries and even more than one day in smaller ones) by obtaining on-line data of the relevant analytes. After optimisation of the method, further odour or taste relevant analytes could be determined simultaneously
Key words:
2,3-pentanedione, beer fermentation, diacetyl, ion mobility spectrometry, process control, quality control.
Publication no. G-2006-0629-409 ©2006 The Institute & Guild of Brewing