Technical mycology : the utilization of micro-organisms in the arts and manufactures a practical handbook on fermentation and fermentative processes, for the use of brewers and distillers, analysts, technical and agricultural chemists, pharmacists, and all interested in the industries dependent on fermentation / by Franz Lafar ; translated by Charles T.C. Salter.

  • Lafar, Franz, 1865-1938.
Date:
1910-1911
Catalogue details

Licence: In copyright

Credit: Technical mycology : the utilization of micro-organisms in the arts and manufactures a practical handbook on fermentation and fermentative processes, for the use of brewers and distillers, analysts, technical and agricultural chemists, pharmacists, and all interested in the industries dependent on fermentation / by Franz Lafar ; translated by Charles T.C. Salter. Source: Wellcome Collection.

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    (XXIV., V.) retained their vitality for many years (up to seven- teen). Sacch. Ludwigii proved less hardy, some of the samples dying within one-two years, though others lasted six years; and Carlsburg bottom yeast No. 2 behaved in a similar manner. To these exceptions must be added the Sacch. theobromce isolated by A. Preyer (I.) from putrefying cocoa, and also—according to J. C. Holm (II.)—a few species of Schizosaccharomyces, one of which perished within a year in saccharose solution, though found to be still living in wort after two and a half years. Beer wort, on the other hand, proved unreliable with all the others tested for this purpose. True, in not a few instances, living cells were found in it after ten or even eleven years, but just as frequently none could be detected at the end of a single year. This liquid is subject to considerable variations in constitution which cannot be influenced or ascertained by the experimenter. In countries where the summer is hot, provision must be made at that season for artifi- cially cooling the cultures (in an ice-chest of special construction); otherwise, as was observed by H. Will (XIX.) in Munich, and by A. Kukla (I.) in Prague, degeneration and death will occur even with saccharose solution. I11 consequence of unfavourable expe- riences, A. Jorgensen (IX.) recommends that streak cultures on wort gelatin should not be employed for storage purposes. The tendency to and results of the formation of films on ageing cultures have been already referred to on p. 120, vol. ii. The colour of beer wort is ameliorated by the fermenting yeast, not solely (as is known to every brewer) during primary fer- mentation, but also, and to a far greater extent, when the fer- mented beer is left for a long time in contact with the sedimental yeast, as is the case when yeast cultures are stored in wort. A gradual and extensive decoloration of the nutrient medium occurs (see p. 126, vol. ii.); so much so, in fact, that the colour may be changed from brown to pale straw-yellow. The experiments con- ducted on this point by H. Will (XXV. and XXII.) showed that the wild yeasts generally are more powerful decolorants than the culture yeasts. When a pure culture has to be transferred from one laboratory to another, which possesses the necessary equipment for further reproduction, a small quantity of the culture—even a couple of vigorous cells will suffice—is placed on a little cotton-wool and inserted in a previously sterilised Freudenreich or Freudenreich- Hansen flask. The cotton should not have been freed from fat, and will then be hygroscopic enough to supply the yeast with the requisite minimum of moisture to prolong its vitality. The Hansen modification of the Freudenreich flask (Fig. 162) differs from the original type by the provision of a slanting tube at the side to facilitate connection with a Pasteur flask, both for intro- ducing a drop of the transferred culture on to the cotton (e) and also for inoculating it into a fresh nutrient solution, A coating