The effect of pitching rate on fermentation, maturation and flavour compounds of beer produced on an industrial scale

Abstract

The aim of the study was to determine the effect of the initial number of yeast cells in the wort on the process of fermentation, maturation and the content of the volatile components of beer, as well as the viability and vitality of the yeast biomass. The experiments were performed on an industrial scale, with fermentation and maturation in cylindro-conical fermentation tanks with a capacity of 3800 hL. Yeast for pitching was collected after secondary fermentation (third passage) and wort pitching levels were 5 × 10 6 , 7 × 10 6 and 9 × 10 6 cells/mL. During fermentation and maturation, the changes in the content of the extract, yeast growth, yeast vitality and selected volatile components were investigated. Experiments showed that the yeast inoculum had a significant impact on the course of the fermentation and metabolic changes. With increasing numbers of cells introduced into the wort, the content of the esters and fusel alcohols increased, while the acetaldehyde concentration decreased. These changes affected the final quality of the beer.

Screening and Application of Cyberlindnera Yeasts to Produce a Fruity, Non-Alcoholic Beer

“…Acetaldehyde concentrations were only dependent on the pitching rate, with increasing amounts of acetaldehyde found at lower pitching rates ( Figure A1). This result correlates with other studies that found a decrease in acetaldehyde with increasing pitching rate in wort fermentations with brewers' yeasts [48,49]. However, overdosing yeast (>5 × 10 7 cells/mL) can lead to an increase in acetaldehyde again, as observed by Erten et al [50].…”

The effect of temperature on fermentation and beer volatiles at an industrial scale

“…The sensory characteristics of beer are influenced by aromatic compounds formed by yeast during fermentation . The quantity of volatile compounds depends on the composition of the wort, aeration level, pitching yeast, process temperature and tank filling regime . The speed of the fermentation process is important in process control .…”

The Production of Secondary Metabolites with Flavour Potential during Brewing and Distilling Wort Fermentations

“…Higher fermentation temperature [27] Increased esters and alcohols Trub present in the fermenter [31,32] Reduced esters of increased alcohols Yeast nutrients added to wort [27] Increased esters and alcohols Increased wort oxygen at pitching [33] Reduced esters Pressure fermentation [34] Reduced esters, carbonyls and alcohols Higher wort gravity [12,35] Increased esters and alcohols Increased wort maltose [36,37] Decreased esters Increased wort lipids [38] Decreased esters …”