Spectrophotometric determination of the iodine value of brewery spent grain
Brewery spent grain, wet spent grain, dry spent grain
High molecular weight dextrins and starch present in the wort extracted from brewery spent grain are precipitated through the addition of ethanol, centrifuged and dissolved in phosphate buffer, followed by the addition of an iodine solution. Depending on the molecular weight and degree of branching, a red to blue color forms, the intensity of which is measured spectrophotometrically at 578 nm.
Applicable for all (laboratory) worts
Medium and high molecular weight proteins are precipitated by phosphomolybdic acid. The nitrogen is determined in the filtrate. Therefore, the results express the amount of low molecular weight proteins.
Determination of the SGA20/20 submerged weight ratio of a liquid
Wort, beer, beer-based beverages, NAB, beverages, liquid
By precisely weighing the volume of a solution (wort or beer) against the same volume of a reference solution (water) at 20 °C, the relationship of the submerged weights (specific gravity), which are dependent on their buoyancy, is calculated through division and is expressed as SGA20/20 [1].
This method describes how to determine the thousand kernel weight of barley.
Barley intended for the production of malt is evaluated on the basis of the thousand kernel weight.
This test is based upon determining the number of barley kernels in a subsample of a defined weight, i.e., the calculation of the weight of 1000 kernels of barley.
This method describes how to determine the hectoliter weight of barley.
Barley intended for the production of malt is evaluated on the basis of the hectoliter weight.
The hectoliter weight determines how many kilograms 100 liters of barley weighs. For this analysis, the weight of a defined sample volume of barley is determined, and the corresponding hectoliter weight is calculated.
One hectoliter of malting barley generally weighs between 68 and 75 kg, although higher values are not unusual (up to 78 kg).
This method describes how to determine the thousand kernel weight of malt.
Barley malt intended for use in beer brewing or elsewhere in the food industry.
The thousand kernel weight is more meaningful for evaluating malt quality than the hectoliter weight. A relationship exists between the thousand kernel weight and both the sieving test and the extract yield of malt, since the percentage of extract contained in malt increases with increasing thousand kernel weight, given that the protein content remains constant. The thousand kernel weight rises with increasing moisture content of the malt; therefore, it must be calculated in reference to the dry substance of the malt to produce an objective measurement [1].