24 PURE CULTURES OF 



use could it be to have sterile wort when the pitching yeast was 

 contaminated with disease germs ? Moreover, the construction 

 of Velten's apparatus was in several respects defective ; this 

 was especially the case with the method adopted for sterilising 

 the air, which was effected by heat in accordance with 

 Schwann's method. The present director of the brewery, 

 Captain Kuhle, introduced cotton-wool filters, in accordance 

 with my suggestion ; and through his experiments, extending 

 over several years, the Old Carlsberg apparatus has been 

 gradually brought to its present highly practical form.* It 

 was only after the yeast question had been solved that the 

 question of the abolition of open coolers was justified, and it 

 was only then that Jacobsen introduced the apparatus 

 mentioned above. An apparatus constructed on the same 

 principle, but differing in several respects from the above, has 

 been erected in New Carlsberg by C. Jacobsen. In the 

 second German edition of this book I expressed myself as 

 follows in connection with this subject : " The time has now 

 come, and there is therefore no doubt that this improvement 

 will gradually find its way into several of the breweries where 

 pure yeast has stood the test, and it will thus serve to perfect 

 the new system." This has also been fulfilled ; the Old 

 Carlsberg apparatus has served as a model for a number 

 of imitations and modifications brought out especially in 

 Germany. A. Bergh's centrifugal machine has also recently 

 been adopted for the same purpose.! 



In the foregoing account I have in the main only referred 

 to low-fermentation breweries. That my work, however, 

 with suitable modifications is also profitably adapted to the 

 requirements of high-fermentation breweries and the other 



* A description of this apparatus and its employment will be found in 

 J. C. Hollm's paper, " Die Vorrichtungen in der Brauerei zur Kuhlung und 

 Lliftung der Wiirze " (Zeitschr. f. das ges. Brauw., 1887, No. 20), and in " Einige 

 Bemerkungen liber das Liiften der Wiirze," by A. Petersen (ibid., 1888, No. 3). 



t See the paper by Jorgensen and P. Poulsen, in Zeitschr. f. d. ges. Brauw., 

 1890. 



