Brewing Yeasts

Branke, /. (Brewing) yeast tub. brannte, pret. (of brennen) burned, etc. 

Timmins, E. M. Quain, D. E. Goodacre, R. Differentiation of brewing yeast strains by pyrolysis mass spectrometry and Fourier transform infrared spectroscopy. Yeast 1998,14,885-893. 

Joubert R et al. Two-dimensional gel analysis of the proteome of lager brewing yeasts. Yeast 2000 16 511-522. 

Supplemental vitamins shall originate from geminated grains, fish liver oil, or brewing yeast. When natural vitamin sources cannot be provided, synthesized vitamin products can be used if they are approved by OFDC. 

Daenen, L., Saison. D., Sterckx, F., Delvaux, E.R., Verachtert, H. DerdeUnckx, G. (2007). Scrre-nening and evaluationof the glucoside hydorlase activity of Saccharomyces and Brettanomyces brewing yeasts. J.Appl. Miocrobiol. doi 10.1111/J.1365-2672.2007.03566.X... 

Duan, W., Roddick, F. A., Higgins, V. J., Rogers, P. J. (2004) A parallel analysis of H2S and SO2 formation by brewing yeast in response to sulfur-containing amino acids and ammonium ions. Journal of the American Society of Brewing Chemists, 62, 35 1. 

Oshita, K., Kubota, M., Uchida, M., Ono, M. (1995) Clarification of the relationship between fusel alcohol formation and amino acid assimilation by brewing yeast using C-labelled amino... 

Derivation A ferment obtained in brewing. Yeasts induce fermentation by enzymes (zymases) that convert glucose and other carbohydrates into carbon dioxide and water in the presence of oxygen or into alcohol and carbon dioxide (or lactic acid) in the absence of oxygen. 

Joubert, R., Strub, J.-M., Zugmeyer, S., Kobi, D., Carte, N., Van Dorsselaer, A., Boucherie, H., and Jaquet-Gutfreund, L. 2001. Identification by mass spectrometry of two-dimensional gel electrophoresis-separated proteins extracted from lager brewing yeasts. Electrophoresis 22, 2969-2982. 

V. A. Nedovic, B. Obradovic, I. LeskoSek-Cukalovi, O. Trifunovic, R. Pesic, and B. Bugarski. Electrostatic generation of alginate microbeads loaded with brewing yeast. Process Biochemistry, 37(l) 17-22, September 2001. 

Classification of brewing yeasts and selection of suitable strains for brewing receive some treatment in Chapters 18 and 19. 

The membrane is composed of lipid and phospholipid and contains proteins and sterols. The absolute requirement for unsaturated fats and sterols in membranes accounts for much of the oxygen requirement of brewing yeast strains (see Chapter 18). The nature of the unsaturated fats in the cell membrane affects its properties, e.g. in relation to ethanol tolerance [30]. 

The yeast cell wall confers certain important properties from the point of view of brewing. Thus, some brewing yeasts rise to the surface of the fermenting wort towards the end of fermentation (top yeasts) while others sediment (bottom yeasts). This distinction is a reflection of differences in composition of the yeast cell wall, although the chemical nature of these differences is not known. The ability of top yeasts to accumulate at the liquid-air interface can be demonstrated in water [51]. Shaken in a very clean tube, the yeast persists so well at the interface that what appears to be a type of skin is visible at the meniscus. Bottom yeasts fail to form such a skin and this simple test is therefore valuable in practice for distinguishing between top and bottom yeasts. Other factors are undoubtedly involved in head-formation such as the transport of yeast clusters to the surface on the interfaces of carbon dioxide bubbles. Chains of cells or loosely-packed floes are particularly favoured by such flotation. 

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