Fluidization and foam separation in brewing: quantitative analysis of CO2 bubble behavior and its influence on fluidization and froth formation in fermentation tank, part I.

Kojima, K., Suga, S., Oka, K., Moriwaki, S. and Nagami, K.

Abstract
Investigations into the relationships between the behaviour of carbon dioxide bubbles generated during fermentation in a cylindro conical tank and the flow patterns in the fermenting wort and formation of form on its surface are described. A quantitative data analysis related the diameter, upward velocity, numbers at a given point per unit of time, etc., of the bubbles to the "void fraction" (the percentage of the total volume accounted for by the volume of gas in the bubbles). Correlations between the void fraction and both the vertical velocity of currents in the fermenting wort and the height of the foam head were evaluated, showing that the volume of carbon dioxide produced is directly related to both parameters. It is therefore concluded that monitoring the void fraction is potentially useful as an aid to process control in brewery fermentations.
Keywords : carbon dioxide fermentation flow foam measurement