Whole hops intended for use in beer brewing or elsewhere in the food industry
Evaluation of the appearance of hop cones is performed through visual inspection and sensory assessment.
Hops and hop products intended for use in beer brewing or elsewhere in the food industry
The respective constituents of hops are not uniformly distributed throughout the cones. The aroma compounds and bitter substances are found in the lupulin glands inside the cone, adhering to the cone bracteoles near the strig. The polyphenols, on the other hand, are found in the bracts, bracteoles and stems. In order to reliably analyze the constituents of hop cones, homogenization of the sample is required. For this purpose, the cones are ground and the sample is divided.
Hops with high moisture content have a shorter storage life; in contrast, hops that are too dry disintegrate easily and lose their lupulin.
Hops and hop products intended for use in beer brewing or elsewhere in the food industry
The moisture content of whole hops, hop powder products or pellets is determined through the difference in weight before and after drying under standardized conditions.
Hops and hop products intended for use in beer brewing or elsewhere in the food industry
Hop constituents are distributed between an aqueous acidic methanolic phase and diethyl ether. Hop bitter substances extracted with ether are subsequently separated according to their different solubility properties in cold methanol and hexane into fractions: total resins, soft resins and hard resins. The soft resins are further separated according to their capacity to form complexes with lead salts into α-acids (conductometer value) and a β-fraction.
Hops and hop products intended for use in beer brewing or elsewhere in the food industry
After extraction with toluene, the α-acids and β-acids in the hops and hop pellets are determined using spectrophotometry.
Hops and hop products intended for use in beer brewing or elsewhere in the food industry
After milling, hops and hop powder products are extracted using a diethyl ether/methanol mixture and a hydrochloric acid solution. The α-acids and β-acids dissolved in the ether phase are separated using reversed phase high-pressure liquid chromatography (RP-HPLC) and measured spectrophotometrically at a wavelength of 314 nm.
Hop extracts are dissolved in methanol. The α-acids and β-acids dissolved in the methanol are separated using reversed phase high pressure liquid chromatography (RP-HPLC) and measured spectrophotometrically at a wavelength of 314 nm.