The method is suitable for the determination of water vapor volatile aroma compounds in beer.
Volatile aroma compounds are driven out of the sample through steam distillation. The ethanolic distillate is saturated with NaCl. Potassium hydrogen sulfite is added to separate carbonyl groups that might interfere with the analysis. The extraction of the aroma compounds is performed by shaking out with dichloromethane and the phases separated by centrifuging.
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
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.
Hops and hop products intended for use in beer brewing or elsewhere in the food industry
The volatile constituents in hops or hop products are obtained by means of steam distillation. The hydrocarbon and oxygen fractions are separated using a process involving column chromatography.