VIEW ARTICLE    DOI: 10.1094/ASBCJ-46-0104

Fate of Hop Oil Components in Beer. Val E. Peacock and Max L. Deinzer, Department of Agricultural Chemistry, Oregon State University, Corvallis 97331. J. Am. Soc. Brew. Chem. 46:0104, 1988.

Hop oil components in beer can be lost in two ways-migration into the packaging material or chemical degradation. Beer flavor compounds are concentrated in the crown liner of bottled beer. The degree of concentration is dependent on the polarity of the compound. The less polar the compound, the more strongly it is concentrated in the liner. Hop oil hydrocarbons from beer are strongly concentrated, the concentration of ketones and esters varies by chain length, and alcohols are poorly concentrated by the liner. Aroma compounds not derived from hops are also concentrated by the crown liner. The disappearance of linalool, geraniol, humulenol II, and humulene diepoxide A was followed for eight weeks in a beer spiked with these compounds. The floral aroma compounds linalool and geraniol disappeared rapidly in the first two weeks, likely from reaction with oxygen, and afterwards were depleted much more slowly. The rates of disappearance of humulenol II and humulene diepoxide A were much more rapid than for linalool and geraniol, and changed less with time. These compounds likely react in the bottle by oxidation and by acid hydrolysis. Reaction of these compounds may explain the fleeting nature of hop aroma in beer.

Keywords: Bottles, Hop aroma, Liners, Migration, Oxygen