Draught beer hygiene: a forcing test to assess quality

Mallett, James R.; Stuart, Melanie S.; Quain, David E.

Abstract

The quality of draught beer is important to consumers but can be inconsistent, ranging from excellent through to unacceptable. The few but dated studies of draught beer quality have focused on the number of microorganisms that are present in the product. Work reported here, suggests that this approach has its limitations and fails to relate to beer quality post-dispense. An alternative approach using the long-established ‘forcing’ method provides a better but still retrospective assessment of draught beer quality. Samples post dispense are ’forced’ by static incubation at 30°C for four days and beer quality is ranked by the measurement of absorbance at 660nm. The increase in absorbance reflects the growth of beer spoilage microorganisms present in the beer at dispense. Four quality bands are proposed, where quality is described as excellent (absorbance increase of < 0.3), acceptable (0.3-0.6), poor (0.6-0.9) and unacceptable (> 0.9). The method is straightforward, requires no special skills and enables, for the first time, the robust quantification of draught beer quality. It is anticipated that the method will have widespread application in the measurement and improvement of the quality of draught beer.

Citation

Mallett, J. R., Stuart, M. S., & Quain, D. E. (2018). Draught beer hygiene: a forcing test to assess quality. Journal of the Institute of Brewing, 124(1), 31-37. https://doi.org/10.1002/jib.470

• Journal Article Type: Article
• Acceptance Date: Oct 9, 2017
• Online Publication Date: Nov 29, 2017
• Publication Date: Feb 20, 2018
• Deposit Date: Oct 11, 2017
• Publicly Available Date: Nov 30, 2018
• Journal: Journal of the Insitute of Brewing
• Electronic ISSN: 2050-0416
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 124
• Issue: 1
• Pages: 31-37
• DOI: https://doi.org/10.1002/jib.470
• Keywords: Dispense, Beer spoilage, Quality, Method
• Public URL: https://nottingham-repository.worktribe.com/output/912521
• Publisher URL: http://onlinelibrary.wiley.com/doi/10.1002/jib.470/full
• Additional Information: This is the peer reviewed version of the following article: Mallett, J. R., Stuart, M. S., and Quain, D. E. (2017) Draught beer hygiene: a forcing test to assess quality. J. Inst. Brew., doi: 10.1002/jib.470 which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/jib.470/full This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.