Study of the influence of beer composition on the amount of bubbles in beer: CO2, alcohol, protein and iso-alpha-acid contents as primary predictors.

Due to compositional differences, the mouthfeel of non-alcoholic beers (NABs) is considered inferior to that of alcoholic beers (ABs). Carbonation properties are a key sensation regarding mouthfeel. This study quantified the amount of bubbles in ABs (n = 10) and NABs (n = 9), ranging from 3.5 to 33.2 bubbles/cm2. Notably, NABs produce significantly less bubbles. After an extensive physicochemical characterisation of the beers, the relationship between beer composition and bubble quantity was investigated using response surface methodology. The model showed that the amount of bubbles was predominantly influenced by the CO2 content and the dynamic surface tension at low surface ages (200 ms). In turn, this surface tension was mainly governed by the presence of alcohol, although in NABs proteins and iso-alpha-acids also exerted a significant impact. The amount of bubbles in NABs may be improved by increasing the CO2 content or adding components that reduce the surface tension at low surface ages.