The Effect of Pitching Rate on Fermentation and Flavour Compounds in High Gravity Brewing

摘要

The effect of pitching rate on fermentation and production of flavour compounds was studied in high gravity wort using a lager yeast. Fermentation performance was followed by monitoring the total sugar content and yeast growth. Volatile compounds were evaluated by analysing higher alcohols, esters and carbonyl compounds at the end of fermentation. Faster fermentation rates and higher yeast counts were observed with the higher pitching levels. Lower amounts of 2- and 3-methyl-1-butanols and higher levels of 2-methyl-1-propanol were found at the increased pitching rates. The concentration of isoamyl acetate was reduced with an increased pitching rate. Higher amounts of diacetyl and 2,3-pentanedione were obtained at the lower pitching levels.