Foam stability represents an important quality attribute of beer and therefore must remain under constant scrutiny. The amount of foam formation is dependent on the carbon dioxide content of the beer, which can be adjusted to the value desired in the brewery. On the other hand, the capacity for foam formation and the stability of the foam are dependent on the composition of the beer (protein fractions > 12,000 Da, glycoproteins, iso-humulones, β-glucans, heavy metals).
This method describes how to determine the foam stability by means of the Ross and Clark method.
beer and beer-based beverages
CO2 is introduced into the beer so that a specific volume of foam is produced. The mean retention time of the bubbles in the foam serves as a measure for the foam stability, which is calculated as the relationship between the time required for the foam to collapse and the logarithm of the relationship between the volume of the collapsed foam and the foam still present [1–3].
This method is frequently applied in instances when the influence of carbon dioxide content on foam formation in the beer is to be eliminated.