The Importance of Wort Composition for Yeast Metabolism During Accelerated Brewery Fermentations

125thAnniversary Review: Developments in brewing and distilling yeast strains

“…Compared with other media employed for potable and industrial alcohol productionmust, cane juice, molasses-based media, apple/pear juice, various syrups, etc.wort is a very sophisticated medium. It functions as both a growth medium to develop new yeast cells and as a fermentation medium for the yeast to produce ethanol, carbon dioxide and other metabolic products, many of which influence the flavour of the beer and spirits (47). Later it will be discussed that, without the correct genetic make-up (genomic aspects), the yeast strain cannot conduct effective growth (proteomic aspects) and complete wort fermentation will not occur.…”

“…Gibson (130) reviewed the area of high-gravity brewing and wort enrichment and supplementation in 2011 as one of the 125th anniversary reviews. In addition, very high-gravity brewing (VHGB) has also recently been reviewed (47). Highgravity brewing was developed in the 1960s, 1970s and 1980s primarily to reduce capital expenditure.…”

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

“…In contrast, Dekoninck et al (9) pointed out the difficulties in obtaining an acceptable level of diacetyl in beer produced from a concentrated wort (HBG -High Gravity 15.5°P) with the use of high doses of yeast. Similar results were obtained by Nguyen and Viet Man (6), who stated that an increase in the concentration of diacetyl is the result of the introduction of higher doses of inoculum.…”

The Microbiology of Malting and Brewing

“…Most brewers simply regulate the strength of the wort (degrees Plato) and pitch on that basis, assuming that the relative balance of the diverse nutrients within the feedstock is consistent and modulated by the malt selection and how that malt is processed in the brewhouse. To a first approximation, this seems to be a reasonable situation on an experiential basis, although there are two variables that many brewers do seek to regulate more closely, i.e., the clarity of the wort and the concentration of zinc ions (89,90), although other additions to promote fermentations, particularly those with higher-strength wort, may be employed (91,92). The presence of insoluble particles in wort (which are derived in the brewhouse and are present at a level in inverse proportion to the extent that they are removed in clarification stages prior to fermentation) promotes yeast action by their ability to nucleate carbon dioxide, thereby releasing bubbles (93).…”