​P-44. Antifoams from hops

Presenter: Yves-Yannick Ford, Barth Innovations Ltd., Paddock Wood, Kent, United Kingdom. Coauthor(s): Keith Westwood, Barth Innovations Ltd., Paddock Wood, Kent, United Kingdom; Andreas Gahr, Hopfenveredlung St. Johann GmbH & Co. KG, Train-St. Johann, Germany; Agnieszka Rajca Ferreira, formerly at Botanix Ltd., Paddock Wood, Kent, United Kingdom; Katarzyna Wolinska, Barth Innovations Ltd., Paddock Wood, Kent, United Kingdom; Mita Lad, University of Nottingham, Nottingham, United Kingdom.

Control of foaming is important during brewing operations, especially at the fermentation stage. We have developed hop-based solutions for this problem. These are emulsions of hop extracts in water that show effective antifoam action together with potentially beneficial effects on the final beer. Pilot brewery trials were conducted, using the hop extract emulsions as antifoam agents during fermentation, to assess both the antifoam performance and the effects on the final beer. A dose rate of 10–50 g/hL of the emulsions successfully suppressed foaming to the same extent as commercial silicone antifoam used at the recommended 5 mL/hL. Use of the hop extract emulsions increased utilization of the hop bitter acids so that the final beers had elevated levels of bitterness compared to the control (no antifoam). In addition, the hop extract emulsions also had a positive effect on the final beer foam stability. The positive effects on hop acid utilization and on beer foam stability are thought to be at least partly due to decreases in losses of iso-α-acids. Iso-α-acids will partition into the foam phase, and thus, partial loss of these components is likely due to foam deposition on vessel walls, etc. The positive results from the brewing trials have encouraged us to further develop the formulation to enhance effectiveness. A simple, rapid, and reproducible method has been devised to test antifoam performance in the laboratory, and results are presented to show that this method is a reliable predictor of antifoam performance in a pilot brewery trial. Since the products are based on hop extract and natural emulsifiers, the stability, both in terms of performance and microbiological contamination, is important. Data from storage trials conducted under ambient conditions, and under accelerated aging at 30–40°C, show that the emulsions remain microbiologically clean and effective as antifoams for at least 12 months.

Yannick Ford studied biochemistry at the University of Oxford (1987–1991), and continued his studies at Oxford for a doctorate in plant biochemistry (1991–1995). He then worked for nine years at Horticulture Research International on a variety of research projects, with a particular interest in plant secondary metabolites and their potential beneficial effects. He joined Botanix Ltd., a member of the Barth Haas Group, in 2004, and has worked in both research and regulatory affairs roles. In 2010 Yannick transferred to Barth Innovations Ltd. as research chemist and regulatory affairs manager and continues to work on development of new products for brewing applications.

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