Fermentation organisms : a laboratory handbook / by Alb. Klöcker; translated from the german by G. E. Allan and J. H. Millar.

Date:
1903
Catalogue details

Licence: In copyright

Credit: Fermentation organisms : a laboratory handbook / by Alb. Klöcker; translated from the german by G. E. Allan and J. H. Millar. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    only exceptionally used. If a clear wort is desired, filtered wort, i.e., wort which has been passed through the filter bags in the brewery, can be used. An absolutely clear wort is obtained by setting this aside and allowing it to take up oxygen from the air; a deposit forms at the same time. If the method of boiling on the sand bath is employed for sterilisation of the wort, the latter must be diluted with sterile water on account of the great evaporation which takes place, so that the concentration may be approximately the same after sterilising as before ; usually a mixture of 7 parts of wort and I of water will be found most suitable. The dilution is unnecessary when steam heating is used for sterilising. Wort contained in Pasteur flasks is sterilised on the sand batli in the following manner : The wort is boiled t*or an hour ; during the first three-quarters of an hour the steam is allowed to pass out of the side tube through the open rubber tubing; the glass plug after being sterilised in the flame is then put into the tube so that during the remaining time the steam only passes through the bent tube. As soon as the flask is removed from the sand bath, the tube is closed with the asbestos plug. The air which passes in as the flask cools is sterilised by its passage through the hot tube. Later on, after the tube has cooled, the current of air passes very slowly through the tube and is thus filtered by the asbestos. The wort in the diflerent flasks is sterilised by means of steam at ordinary pressure for a half to three-quarters of an hour, large flasks with 70 c.c. of wort requiring three- quarters of an hour, the smaller flasks, e.g., the Freuden- reich, half an hour. After sterilisation it is advisable to let the flasks remain at least fourteen days before use in order to be able to judge to what extent the wort is sterile. During this time the