P-18
Bitterness contribution of alpha-acids in lager beer
Presenter: Annette Fritsch, Department Food Science and Technology, Oregon State University, Corvallis, OR
Co-Author: Thomas Shellhammer, Department Food Science and Technology, Oregon State University, Corvallis, OR

The bitter contribution of alpha-acids has generally been accepted as minimal to overall beer flavor, but many brewers have observed an increase in bitterness when dry-hopping a beer. The objective of this study was to examine the impact of alpha-acids on beer bitterness by dosing commercial lager beer with purified alpha-acids. Varying levels of alpha-acids (91% pure) were added up to 28 ppm to a commercial lager beer with 8 BU of inherent iso-alpha-acid bitterness. A trained beer panel (n=11) wearing nose clips was presented with a series of triangle tests to establish differences in bitterness between beers with and without added alpha-acids. The same panel evaluated all treatments without nose clips to evaluate beer flavor. The panel found no significant difference in bitterness among the samples, while a slight difference in aroma perception was observed. High levels of alpha-acids can affect the flavor of lager beer, but the contribution of alpha-acids to the overall bitterness is insignificant.

Annette Fritsch received a B.S. in food science from The Ohio State University. She began employment with Givaudan Flavors Corporation in June 2001 as a product developer in the savory applications laboratory of the Research and Development Center. During her employment, she functioned as a manager, team leader, customer contact, and performed product presentations to clients. She began her graduate research at Oregon State University in August 2004 and has been a member of ASBC since October of 2004.