Fermentation - the "black box" of the brewing process.

Stewart, G.G. and Russell, I.

Abstract
Current knowledge of fermentation (which is less well understood than either wort production or post fermentation beer processing) is reviewed. Different aspects of the subject are discussed separately according to whether they are well understood (e.g. diacetyl metabolism), in the process of becoming better understood (e.g. the factors influencing the uptake of fermentable sugars from wort) or still poorly understood at the time of writing (e.g. the toxic effects of excessive ethanol concentrations and the factors limiting the ability of yeast to ferment very high gravity worts). The improvements in the efficiency and controllability of the fermentation process, with consequent benefits in terms of economic performance and product quality, arising from the knowledge already gained, are also discussed together with the further improvements to be expected from continuing discoveries relating to aspects which are still not well understood and the problems arising from areas where knowledge remains inadequate. The probable future direction of research into brewers' yeast and brewery fermentation is also briefly discussed.
Keywords : brewers' yeast fermentation research development survey