This method describes how to determine the hop storage index (HSI) in hops and hop products.
Hops and hop products intended for use in beer brewing or elsewhere in the food industry
The oxidative degradation of the α-acids and β-acids in hops and conventional hop products is determined using a spectrophotometer. The HSI can be referenced in addition to or together with the spectrophotometric method for determining the α-acids and β-acids in hops outlined under R-300.04.110 α- und β-Säuren in Doldenhopfen und Hopfenpellets – Spektralphotometrische Methode.
Barley malt intended for use in beer brewing or elsewhere in the food industry
High-molecular weight dextrins and starch present in the wort extracted from brewery spent grains are precipitated through the addition of ethanol, centrifuged and dissolved in phosphate buffer, followed by the addition of an iodine solution. Depending upon the molecular weight and degree of branching, a red to blue color forms, the intensity of which is measured spectrophotometrically at 578 nm.