The wort analysis methods are written, for example, for wort that is produced using the Congress mash method. These methods may also be applied in the analysis of wort which has been produced using a different mash method, particularly the isothermal 65 °C method. However, the reference values listed in the analysis method for Congress wort are not transferable.
The thiobarbituric acid index is a measure of the cumulative thermal stress brought about by exposure to heat (intensity) in malt and wort. The TBI is a key indicator, which detects the presence of numerous Maillard reaction products in addition to 5-hydroxymethylfurfural (HMF) and other organic compounds.
Applicable for malt (or the wort produced from it) and all (laboratory) worts
The analysis sample (e.g., Congress wort or wort from above the grain bed during lautering) undergoes a chemical reaction with an acetic acid/thiobarbituric acid solution; the resulting product is yellow in color and is measured spectrophotometrically.