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.
This method describes the determination of the pH value of (Congress) wort. pH influences the enzymatic degradation processes during mashing and determines the solubility of proteinaceous substances, hop bitter substances and the increase in color during wort boiling. Moreover, a relationship exists between the pH of the cast-out wort and that of the beer produced from it. Beer with a high pH shows a tendency toward low physico-chemical stability manifested in the form of turbidity, a consequence of poor protein coagulation in the brewhouse. Therefore, measuring the pH of wort and beer belongs in a brewery’s routine quality control program.
Today, pH is determined largely electrometrically.
Malt intended for use in beer brewing or elsewhere in the food industry
The value of pH is defined as the negative decadal logarithm of the concentration of hydrogen, or more precisely, hydronium ions:
\(\text{ pH }=-\log{ c_{ H_{ 3 }O^{ + } } }\)
The pH scale, ranging from 0–14, is based on the dissociation equilibrium.
The pH value of a liquid is commonly determined with a pH measurement device consisting of the measurement electrode (glass) and the reference electrode (e.g., silver/silver chloride electrode), which is connected to a signal amplifier and a display instrument. The device is calibrated using standard buffer solutions.
The pH reading displayed is determined through the difference in electrical potential between the reference solution in the electrode and the solution being measured.
Generally, a pH measurement system is used, in which the measurement and reference electrodes are combined to form a single unit.