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 high-molecular weight proteins in wort and beer by precipitating them with magnesium sulfate
This method is suitable for wort and beer.
The high molecular weight proteins are precipitated by magnesium sulfate, and the nitrogen content in the sediment is determined, e.g., according to Kjeldahl.
In order to measure the portion of the high molecular weight protein fractions in wort and beer, precipitation with magnesium sulfate is recommended. Through gel chromatography it has been established that magnesium sulfate precipitates nitrogenous compounds possessing molecular weights of approximately 2600 Da and higher [2]. A strong correlation between the nitrogenous substances precipitated by magnesium sulfate and beer foam has also been observed [3, 4].
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).