Carbon Dioxide and Its Relevance to Large-Scale Brewery Fermentation

摘要

In order to investigate the role of fermenter size and geometry in beer flavor and aroma formation, several aspects of brewery fermentation were studied. In chapter 2, a theoretical analysis of large-scale brewery fermentation is presented. By means of this analysis, the main phenomena related to the effect of fermenter size and geometry were identified, and their relative contribution assessed. Chapter 3 deals with the fluid dynamics of large-scale brewery fermentation. The study included experiments in which the relationship between carbon dioxide formation by yeast, carbon dioxide gas-liquid transfer and liquid circulation rates was investigated. Chapter 4 describes a biochemically-structured model for yeast growth and metabolism during brewery batch fermentations. The validity of the model was tested using laboratory-scale fermentation experiments. The yeast growth model was also used to characterize the effect of carbon dioxide pressure on yeast growth and metabolism, as reported in chapter 5. The relationship between carbon dioxide pressure and the formation of esters and fusel alcohols is described in chapter 6. In the general discussion, the results of experiments presented in the previous chapters are put into perspective.