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Hops
,→The Freshening Power of the Hop (Hop Creep)
[https://www.mdpi.com/2311-5637/7/2/66/html Bruner et al (2021)] investigated whether or not yeast strain selection has an impact on hop creep with the goal of finding if any strains would reduce the potential for dry-hop creep. They examined 30 different ''Saccharomyces'' yeasts from different yeast labs, and measured the [https://beerandbrewing.com/dictionary/gaKDNn0yxE/ real degrees of fermentation (RDF)] that occurred after dry-hopping post fermentation. With the exception of two strains, all of the yeasts re-fermented the beer after dry hopping, indicating that yeast strain selection won't reduce the chances for dry hop creep. There were two exceptions to this. The first was a diastatic strain of ''Saccharomyces cerevisiae'' (SafAle™ BE-134), which was able to break down starches in the beer prior to dry hopping due to the [[Saccharomyces#Diastatic_strains_of_Saccharomyces_cerevisiae|diastatic properties]] of this yeast strain. The other exception was a strain of ''Saccharomyces mikatae'' that is used as a co-fermenter in wine fermentations and is a poor attenuater of wort. The study also found no correlation between flocculation and attenuation from dry-hop creep, but suggested that further research be done to investigate the belief that higher flocculating strains could reduce the negative effects of dry hop creep <ref>[https://www.mdpi.com/2311-5637/7/2/66/html Bruner J, Marcus A, Fox G. Dry-Hop Creep Potential of Various Saccharomyces Yeast Species and Strains. Fermentation. 2021; 7(2):66. https://doi.org/10.3390/fermentation7020066.]</ref>.
A Masters thesis by Tanriverdi (2024) demonstrated that that longer contact times of hops in beer significantly promoted enzymatic activities involved in glucose production, maltose degradation and isoamyl acetate hydrolysis. The same observations were evidenced at higher temperatures. It was noted that a dry heat treatment of hops prior to incubation revealed to reduce the release of glucose and the hydrolysis of isoamyl acetate. Surprisingly, only a high dosage of 10% v/v ethanol in beer resulted in inhibition of amylolytic enzymes. For this dosage, esterase activity remained intact. Concerning the influence of hop variety, only amylolytic enzymes of Simcoe hops exhibited pronounced activities compared to other varieties. Finally, cryo pellets exhibited lower enzymatic activities compared to T90 pellets and whole cones, which indicates that enzymes could be mainly found in vegetative material <ref>[https://dial.uclouvain.be/memoire/ucl/en/object/thesis%3A48802 Tanriverdi, Yudum. Influence of the residual enzymatic power of hops added during fermentation and/or maturation on beer stability. Faculté des bioingénieurs, Université catholique de Louvain, 2024. Prom. : Collin, Sonia ; Willemart, Guillaume.]</ref>.
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