wort, beer
High molecular weight dextrins and starch present in wort or beer are precipitated through the addition of ethanol, centrifuged, dissolved in phosphate buffer, followed by the addition of an iodine solution. Depending on the molecular weight and degree of branching of the erythrodextrins and starch, a red to blue color forms, the intensity of which is measured photometrically.
beer, beer-based beverages, non-alcoholic beverages, mineral water
One of the basic prerequisites for properly conducting sensory analysis is selecting suitable candidates as members of the tasting panel.
The method describes how to determine the iron content of water photometrically with a cuvette test.
Iron(II) ions form a rust-colored complex with 1,10-phenanthroline. Iron(III) ions are reduced to iron(II) ions.
The method describes how to determine the manganese content of water photometrically with a cuvette test.
Manganese(II) ions react in an ammonia solution with formaldoxime, forming a reddish-colored complex.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
Ammonium ions react at a pH of approx. 12.6 with hypochlorite ions and salicylate ions in the presence of sodium nitroprusside, which serves to catalyze the reaction, to form a green color (indophenol blue).
The method describes how to determine the sulfate content of water by means of a photometric cuvette test.
In the presence of barium chloride, sulfate ions form barium sulfate, which is only slightly soluble in water. The turbidity produced by doing so is determined with a photometer.