Contribution of β-amylase from hops to the fermentability of dry hopped beer
DOI:
https://doi.org/10.58430/jib.v131i2.75Keywords:
dry hopping, hop creep, β-amylase, super attenuationAbstract
Why was the work done: The addition of hops (Humulus lupulus) to beer during fermentation or conditioning is known as ‘dry hopping’. This procedure introduces hop amylases, catalysing unintended fermentation known as ‘hop creep’. The impact of hop creep includes extended attenuation, production of diacetyl off flavour, elevated alcohol formation, and potentially hazardous over carbonation of packaged beer. Enzyme assays and genetic analysis have indicated that hops produce four types of amylases, α-amylase, β-amylase, glucoamylase, and limit dextrinase. It is not known which amylase, alone or in combination, are responsible for the increase in fermentability produced by hops. The goal of this study was to identify the hop amylases responsible for hop creep.
How was the work done: Using forced attenuation assays, the different amylases found in hops were screened for increased fermentability similar to that produced by endogenous hop amylases.
What are the main findings: Barley β-amylase extended fermentability equivalent to that produced by the five hop cultivars examined. This suggests that hop β-amylase alone, potentially explains the increase in fermentability associated with hop creep in dry hopped beer.
Why is the work important: The identification of β-amylase as the enzyme reproducing the increase in fermentability through dry hopping advances understanding of the hop creep phenomenon. Greater knowledge of the mechanisms driving hop creep may lead to new approaches for controlling and avoiding the negative impacts on the quality of dry hopped beer.
Downloads
References
Brown HT, Morris G H. 1893. On certain functions of hops used in the dry-hopping of beers. Brew Guard, 23:93-94, 107-109.
Bruner J, Williams J, Fox G. 2020. Further exploration of hop creep variability with Humulus lupulus cultivars and proposed method for determination of secondary fermentation. Tech Q Master Brew Assoc Am 57:169–176.
Bruner J, Marcus A, Fox G. 2021. Dry-hop creep potential of various Saccharomyces yeast species and strains. Fermentation 7:66.
Champagne A, Boutry M. 2017. A comprehensive proteome map of glandular trichomes of hop (Humulus lupulus) female cones: Identification of biosynthetic pathways of the major terpenoid-related compounds and possible transport proteins. Proteomics 17:1600411.
Cottrell MT. 2023. A search for diastatic enzymes endogenous to Humulus lupulus and produced by microbes associated with pellet hops driving ‘hop creep’ of dry hopped beer. J Am Soc Brew Chem 81:435–447.
De Schepper CF, Buvé C, Van Loey AM, Courtin CM. 2022. A kinetic study on the thermal inactivation of barley malt α-amylase and β-amylase during the mashing process. Food Res Int 157:111201.
De Schepper CF, Michiels P, Buvé C, Van Loey AM, Courtin CM. 2021. Starch hydrolysis during mashing: A study of the activity and thermal inactivation kinetics of barley malt α-amylase and β-amylase. Carbohydr Polym 255:117494.
Evans DE, Collins H, Eglinton J, Wilhelmson A. 2005. Assessing the impact of the level of diastatic power enzymes and their thermostability on the hydrolysis of starch during wort production to predict malt fermentability. J Am Soc Brew Chem 63:185–198.
Evans DE, Dambergs R, Ratkowsky D, Li C, Harasymow S, Roumeliotis S, Eglinton JK. 2010. Refining the prediction of potential malt fermentability by including an assessment of limit dextrinase thermostability and additional measures of malt modification, using two different methods for multivariate model development. J Inst Brew 116:86–96.
Evans E, Van Wegen B, Ma Y, Eglinton J. 2003. The impact of the thermostability of α-amylase, β-amylase, and limit dextrinase on potential wort fermentability. J Am Soc Brew Chem 61:210–218.
Jobe C, Féchir M, Rubottom L, Shellhammer TH. 2025. The importance of variety and regional identity on the dextrin-reducing enzymatic activity of Cascade and Mosaic® hops grown in Washington and Oregon. J Am Soc Brew Chem 83:39–46.
Kirkendall JA, Mitchell CA, Chadwick LR. 2018. The freshening power of Centennial hops. J Am Soc Brew Chem 76:178–184.
Kirkpatrick KR, Shellhammer TH. 2018a. A cultivar-based screening of hops for dextrin degrading enzymatic potential. J Am Soc Brew Chem 76:247–256.
Kirkpatrick KR, Shellhammer TH. 2018b. Evidence of dextrin hydrolyzing enzymes in Cascade hops (Humulus lupulus). J Agric Food Chem 66:9121–9126.
Kossmann J, Lloyd J. 2000. Understanding and influencing starch biochemistry. Crit Rev Biochem Mol Biol 35:141–196.
Kumar P, Satyanarayana T. 2009. Microbial glucoamylases: characteristics and applications. Crit Rev Biotechnol 29:225–255.
MacGregor AW, Bazin SL, Macri LJ, Babb JC. 1999. Modelling the contribution of alpha-amylase, beta-amylase and limit dextrinase to starch degradation during mashing. J Cereal Sci 29:161–169.
Mertens JA, Skory CD. 2007. Isolation and characterization of a second glucoamylase gene without a starch binding domain from Rhizopus oryzae. Enzyme Microb Technol 40:874–880.
Michiels P, Croonen D, De Schepper C, Debyser W, Langenaeken N, Courtin C. 2024. Effective strategies to maximise dextrin formation in brewing. J Inst Brew 130:182–198.
Neugrodda C, Gastl M, Becker T. 2014. Protein profile characterization of hop (Humulus lupulus) varieties. J Am Soc Brew Chem 72:184–191.
Rubottom LN, Shellhammer TH. 2024. Evaluating the impact of high and low kilning temperatures on popular American aroma hops. J Am Soc Brew Chem 82:39–49.
Rubottom LN, Lafontaine SR, Hauser DG, Pereira C, Shellhammer TH. 2022. Hop kilning temperature sensitivity of dextrin-reducing enzymes in hops. J Am Soc Brew Chem 80:75–83.
Stenholm K, Home S. 1999. A new approach to limit dextrinase and its role in mashing. J Inst Brew 105:205–210.
Stockholm A, Shellhammer T. 2020. Hop creep - technical brief. Brewers Association.
Stokholm A, Rubottom L, Shellhammer T. 2020. Evaluating a benchtop fermentation method for estimating dextrin degradation by hop diastatic enzymes during dry-hopping. BrewSci 73:140–148.
Stokholm A, Van Simaeys K, Gallagher A, Weaver G, Shellhammer TH. 2022. Investigating the effect of farm management, soil, and climate on hop diastatic potential. J Am Soc Brew Chem 80:389–400.
Tangphatsornruang S, Naconsie M, Thammarongtham C, Narangajavana J. 2005. Isolation and characterization of an α-amylase gene in cassava (Manihot esculenta). Plant Physiol Biochem 43:821–827.
Young J, Oakley WRM, Fox G. 2023. Humulus lupulus and microbes: Exploring biotic causes for hop creep. Food Microbiol 114:104298.
Downloads
Published
Versions
- 20-07-2025 (2)
- 23-06-2025 (1)
How to Cite
Issue
Section
License
Copyright (c) 2025 Journal of the Institute of Brewing
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
This is an open access article which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed or built upon in any way.
Permission will be required if the proposed reuse is not covered by the terms of the License. In this event, email the Editor in Chief - david.quain@cibd.org.uk - with details of your request.
