Application of Chemically Modified Bitter Compounds in Brewing

Abstract

Iso-α-acids or isohumulones are hop-derived beer constituents formed in the brewing process. Iso-α-acids are light-sensitive; they play a key role in the origin of the well-known light-struck off-flavour of beer. To prevent the negative effect of light, beers are generally stored in lightproof cans or dark bottles. Alternatively, reduced iso-α-acids, resistant to light-induced degradation, can be added to beer. These substances also show a positive effect on foam stability. This paper describes the impact of iso-α-acids, reduced iso-α-acids, tetrahydro-iso-α-acids, and hexahydro-iso-α-acids on brewing; their food legislation frame is also mentioned. Chemical and physical methods of analysis of the substances are also reviewed.