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.
The expected haze-free shelf life of beer is best determined by employing so-called forced aging methods.
Suitable for all beers
Forced aging is the most practical means for determining the duration of shelf life and the potential for haze formation in beer. In the forced aging test, an appropriate number of bottles (at least five) are subjected alternately to temperatures of either 40 °C (untreated beer) or 60 °C (stabilized beer) and 0 °C until the turbidity increases by > 2 EBC formazin units as a result of forced aging.
By multiplying the value determined in performing the test, expressed in ‘days of shelf life at 40 °C or 60 °C’, by a factor specific to beer (conversion factor), it is possible to predict how long a beer will remain free of turbidity or haze in the package.
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.
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
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.