This method describes how to determine the hard resin fraction in hops and hop products; for the procedure, refer to the MEBAK method R-300.03.901 [2016-03].
Hops and hop products intended for use in beer brewing or elsewhere in the food industry
The hard resins are calculated by subtracting the soft resins from the total resins. This yields the hard resin content as a percentage of the total resins.
The method is suitable for the determination of steam-volatile aging indicators in beer.
Volatile aging indicator substances are driven out of the sample through steam distillation. The ethanol distillate is adjusted to be alkaline and saturated with NaCl. The extraction of the aroma compounds is performed by shaking out with dichloromethane and the phases separated by centrifuging. The organic phase is further concentrated in a stream of nitrogen gas. Ammonia solution is added to remove the acids, as the acids would coelute, thus preventing the quantification of important substances.
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.
Hop extract intended for use in beer brewing or elsewhere in the food industry
Ensure prior to performing any analysis that the sample of hop extract is representative, i.e., that the sample is taken from a container of thoroughly homogenized material.
Isomerized hop extract intended for use in beer brewing or elsewhere in the food industry
A representative sample of the hop extract is necessary for the analysis, i.e., the sample should be taken from a completely homogenized container.
wort, beer
The thiobarbituric acid index is a measure of the cumulative thermal stress brought about by exposure to heat (intensity) in malt and wort. The TBI is a figure, which indicates the presence of numerous Maillard reaction products in addition to 5-hydroxymethylfurfural (HMF) and other organic compounds.
The analysis sample (e.g., wort, beer or wort obtained from a standardized method, such as Congress wort) undergoes a chemical reaction with an acetic acid/thiobarbituric acid solution; the resulting product is yellow in color and is measured spectrophotometrically.