Shelf life

Unlike wine and whisky, beer tastes best when consumed fresh. After 6–12 months in storage, beer develops an unpleasant, bitter aftertaste. A study to identify the key substances that cause this bitter taste has been published in the Journal of Agricultural and Food Chemistry.¹

Using quantitative LC–MS–MS profiling, a variety of commercial beers were analysed before and after storage. The researchers were able to identify 56 hop-derived sensometabolites for the first time, and were able to gain an insight into the transformation of the bitter compounds during storage.

The study concluded that the time and temperature dependant proton-catalysed cyclization of trans-iso-α-acids was the predominant reaction that led to the formation of harsh tasting tri- and tetracyclic compounds during storage. Due to their stability they have been suggested as indicator molecules to monitor the ageing status of beer. The study concludes that it offers “a scientific basis for a knowledge‑based optimization of the beer bitter taste by controlling the initial pH value of the beer by technological means and by keeping the temperature as low as possible during storage of the final beverage.’

1. D. Intelmann et al., J. Agric. Food Chem., 59, 1939–1953 (2011).

This story originally appeared in The Column. Click here to view that issue.