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33. Hop swelling behavior during dry-hopping

Jörg Engstle (1), Petra Först (1), Michael Kuhn (1), Matthias Scheidtmann (1); (1) Chair of Process Systems Engineering, Technische Universität München, Weihenstephan, Germany

Technical Session 10: Dry Hopping
Monday, August 15  •  9:45–11:30 a.m.
Tower Building, Second Level, Grand Ballroom

Dry-hopping is of growing importance for breweries. The craft brewing sector, as well as breweries with modern beer styles with emphasized hoppy aroma, highly depend on this process. Nevertheless, losses of up to 50% during classical dry-hopping are reported. Swelling behavior of hop pellets is of considerable importance. Particle size distributions, necessary contact time, possible mass transfer rate, and sedimentation behavior of pellets during dry-hopping depend, among other things, on pellet swelling. Pellet disintegration time, swelling capacity, and swelling velocity are measured via image analysis and sedimentation cylinder. Particle size distributions are determined with sieve analysis and laser diffraction. Different hop varieties, pellet types, and pellets of different aging are analyzed. Swelling behavior is of importance for breweries, equipment manufacturers, and hop corporations. Breweries can lower dry-hopping costs by choosing pellets by means of swelling behavior. Equipment manufacturers and hop corporations can use this data to develop special machines and hop products for dry-hopping.

Jörg studied brewing and beverage technology in Weihenstephan and received his engineering degree in 2012. Currently he is working on his doctoral thesis at the Chair of Process Systems Engineering in Weihenstephan, Technical University of Munich. His field of research is lautering. His main interests are spent-grain cake structure, differential pressure in lautering and the effect of milieu conditions, such as pH value and ionic strength, on the behavior of fine mash particles.