Searching the world of hops and brewing to bring you the latest news and research ... so you don‘t have to!
Thiols like it hot…
How to break down the precursor structures of polyfunctional thiols to increase fruity and tropical aromas in beer is a hot topic in brewing research. This US and Canadian research team tested a series of different brewing yeast strains for their ability to release thiols. They used US-Cascade hops in the brewhouse (late and whirlpool) with no dry hopping addition. They observed that some yeast strains produce more free thiols with higher fermentation temperatures, but they also realised that in this set up the highest concentration of thiols did not correlate with higher intensity of fruity aromas which might be in context with the interaction with other aroma compounds.
R. Samia, A. Shayevitz, T. Fischborn and T. Shellhammer. Best paper of the 39 EBC congress in Lille, Fermentation temperature impacts polyfunctional thiol biotransformation in beer, Brewing Science 2024, https://www.brewingscience.de/index.php?tpl=table_of_contents&year=2024&edition=0007%2F0008&article=93103
…but in Hop volatiles like it cold
Nothing is stable in life, only our wish for stability. This four year study looked into the behaviour of alpha acids and aroma compounds in Citra in Perle pellets packed in oxygen free foils at cold (3°C) and ambient (25°C) temperatures. For the degradation of alpha acids the temperature difference had a huge impact. Losses in cold storage were below 5% while at ambient temperature the losses made up almost 40%. The oil losses were more severe and more variety dependent; the loss during cold storage was about 15% the loss during ambient storage around 30%. Within the aroma compounds specifically the myrcene and ester concentrations decreased. So if you ever have to choose, use the freshest hops you have for aroma purposes.
Zunkel, M., et al : behaviour of important bitter and aroma compounds, Poster 54, at the EBC Congress in Lille, 2024
Mouthfeel in beer
Mouthfeel is often used in sensory analysis for beers, but a definition for mouthfeel nor finding the relevant descriptors is an easy task. This UK Research team presents a very comprehensive overview of descriptors relevant for mouthfeel as well as the physiology behind mouthfeel and proposes a lexicon to be used in sensory analysis.
Wolinska-Kennard, K., et al : exploring mouthfeel in beer, Poster 46, at the EBC Congress in Lille, 2024
Names for key antioxidants in beer
A lot of research on antioxidative components in beer is available, but data for single compounds in this regard is rare. This German Research time has now identified these 10 key antioxidant components: 10 key antioxidants, namely, tryptophan, tyrosine, hordatine A, hordatine B, procyanidin B3, prodelphinidin B3, tachioside (3-methoxy-4-hydroxyphenyl-β-d-glucopyranoside), (+)-catechin, tyrosol, and ferulic acid. A positive effect of these antioxidants on the flavor stability was shown by a slowing of oxygen-dependent aging reactions highlighted in beer storage trials under oxygen atmosphere. Doubling the natural concentration these in beer revealed a limit inhibition of 67% on the degradation of cis-isocohumulone to hydroxy-cis-alloisocohumulone.
Stefan Spreng, Corinna Dawid, Andreas Dunkel, and Thomas Hofmann, Quantitation of Key Antioxidants and Their Contribution to the Oxidative Stability of Beer, Journal of Agricultural and Food Chemistry 2024 72 (29), 16423-16437 DOI: 10.1021/acs.jafc.4c01000
