This method describes how to determine the capacity for water imbibition (moisture uptake) in barley.
Barley intended for the production of malt is evaluated on the basis of its capacity for water imbibition.
Barley is steeped according to a defined scheme, and the absorption of the steeping liquor by the kernels at defined times is determined by calculating the moisture content. The moisture content after 72 h steeping time is used to assess the absorption of steeping liquor or the capacity for water imbibition in barley.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
A specified quantity of water is evaporated, and any remaining moisture is subsequently eliminated in a drying oven. The dry residue is then weighed.
Water intended for use in beer brewing as well as in the production of other foods
Steam-volatile phenols form by bonding with diazotized p-nitroaniline azo dyes; the intensity of the resultant color is measured photometrically following extraction with n-butanol.
The intensity of the color, based on a saturation threshold of phenol of 100 %, is as follows:
phenol 100 % m-xylenol 52 %
o-cresol 147 % p-xylenol 92 %
m-cresol 120 % guaiacol 165 %
p-cresol 21 % pyrocatechol 29 %
o-xylenol 16 % α-naphthol 23 %
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.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
For determination of the dry residue in water after filtration, a certain quantity of filtrate is evaporated until dry. It is subsequently dried in a drying oven to eliminate any remaining moisture.
Boiler water for use in the production of beer and other foods
Analogous to the p and m values obtained in the determination of acid capacity (pH 8.2 and 4.3), this analysis is performed according to W-000.13.031 Acid Consumption (Alkalinity, p-Value and m-Value)/Acid Capacity to pH of 8.2 and/or 4.3 for Water. The alkaline capacity of the boiler water is determined through titration of the sample with 0.1 N sodium hydroxide (instead of hydrochloric acid) to a pH of 4.3 and/or 8.2.