R. DANSBY-SPARKS (1), B. Hollinger (2); (1) University of North Georgia, Dahlonega, GA, U.S.A.; (2) Terrapin Beer Co., Athens, GA, U.S.A.
The isomerization of alpha-acids is facilitated by boiling temperatures, producing intensely bitter iso-alpha-acids. Since hops are the most important factor in the overall bitterness, flavor, and aroma of beer, it is important to know what factors contribute to the concentration of alpha-acids and the extent to which they will be converted to iso-alpha-acids. Many brewers add hops during the whirlpool process, and for some styles of beer, copious amounts are added while the wort is still very hot. This results in increased hop contact times with heated wort. It is generally assumed that hop utilization from whirlpooling is near zero, but this is highly unlikely. To date, the only attempts to determine hop utilization from whirlpooling have used professional tasting panels rather than detection of alpha-, beta-, and iso-acids. The initial goal of this work is to use analytical characterization techniques to quantify hop acid content in real-time during the whirlpool and determine how various factors contribute to hop utilization in the whirlpool. Experimentation of this kind on the commercial brewery scale would be economically impractical. Therefore, a scaled-down model was developed to carefully simulate whirlpool conditions on a laboratory scale. The preliminary results from the study of temperature, time, and wort content will be presented.
Royce Dansby-Sparks is an assistant professor of chemistry at the University of North Georgia. Royce received his Ph.D. degree in analytical chemistry in 2010 from the University of Tennessee, Knoxville, and has worked in both the private and public sectors. He is a home brewer and is a member of the North Georgia Mountain Mashers home-brewing group.