Three main factors may be involved in the control of fermentation: (i) yeast type (ii) wort composition (iii) process parameters. Yeast viability needs to be determined in order that the pitching rate can be adjusted. The pitching rate must be sufficient to ensure a rapid start to fermentation. The actual behaviour of yeast during fermentation is difficult to control. The microbiological purity of yeast is essential to avoid off-flavours and flavour variations. The wort composition is important for the course of fermentation. Methods available do not give a complete picture of the quality of malt and its suitability for present methods of brewing. Better information is also necessary to control carbohydrate composition, wort nitrogen and content of micronutrients, and metals in wort. Control of wort aeration is important to control fermentation, together with pitching rate and temperature of fermentation ion, it controls yeast growth and thus, the flavour of beer. Microbiological control is essential to ensure absence of undesirable microorganisms and the microbiological control system should be developed in such a way that (i) it gives results rapidly (ii) it covers control of bacterial infection (iii) it covers control of wild yeast infections. Equipment for automatic control of a number of process parameters has been introduced, including the Platometer for control of temperature and degree of fermentation.
Keywords: aeration brewers' yeast brewing equipment fermentation process control survey temperature viability