ASBC Methods of Analysis - Hops-12: Hop Storage Index (HSI)
ASBC Methods of Analysis
Hop Storage Index (HSI)
When hop cones or hop products are subjected to prolonged or inappropriate process and storage conditions, an oxidative decrease has been observed in both α- and ;Β-acids content and has been found to be variety dependent. The loss coincides with a progressive increase in the ratio of absorbance at 275 nm (A275) to 325 nm (A325) when the alkaline methanol extract is evaluated with a UV spectrophotometer. Such loss in α- and ;Β-acids and increases in the hop storage index (HSI) ratio may reflect unfavorably on the utility and quality of the hops in brewing. This method calculates the HSI.