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].
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.
Hop extract intended for use in beer brewing or elsewhere in the food industry
SO2 in the Karl Fischer solution creates an ester with methanol, which is neutralized through a reaction with a base. The anions of methylated sulfuric acid are the reactive component in the chemical reaction. In the water titration, the methyl sulfite anions are oxidized by iodine to form methyl sulfate. The endpoint can be determined either by a color change (addition of a starch solution) or electrochemically.
Isomerized hop extract intended for use in beer brewing or elsewhere in the food industry
A representative sample of homogenized material is necessary for the analysis. For this reason, if at all possible, samples of the hops or hop products should be taken from their original packaging for analysis.
Hop products with isomerized or reduced iso α-acids intended for use in beer brewing or elsewhere in the food industry
Hop products with isomerized or reduced iso α-acids are dissolved with methanol. The bitter acids are separated through reverse phase high-pressure liquid chromatography (RP-HPLC) and isocratic elution. They are then measured at a wavelength of 270 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.