58 PURE CULTURES OF 



no back-suction of impure air can occur. That the different 

 operations must further be executed with care cannot be 

 too strongly enforced. If the above instructions are closely 

 and intelligently followed, no difficulties will be encountered. 

 During the years in which the apparatus has been in use in 

 the fermenting cellar of Old Carlsberg, it was occasionally 

 submitted to a thorough examination, but it was always 

 found to be in order. 



It has been mentioned that the apparatus as fitted up at 

 New Carlsberg, requires to be modified in certain directions 

 to suit local conditions. Another modification subsequently 

 introduced by Dr. Elion, consists essentially in the addition 

 of a steriliser. In the above description it was assumed that 

 the boiling-hot, and, therefore, sterile wort was taken from 

 the brewery main before it reached the cooler. This is, 

 indeed, the most practical way of charging the wort cylinder 

 with sterile wort, and this method will, therefore, be selected 

 even in those breweries as for example the Tuborg brewery 

 at Copenhagen where the pipe for this purpose has to be 

 made rather long. There are, in fact, not many breweries 

 in which this arrangement cannot be adopted. When, how- 

 ever, local circumstances do not readily permit of this, the 

 wort must be sterilised by boiling after it has been run into 

 the cylinder, and it is then cooled and aerated in the manner 

 previously described. Working in this manner is more 

 troublesome, and it also takes more time, but the difficulties 

 are not insurmountable. With the view to sterilise the wort 

 in the cylinder, Dr. Elion has surrounded the latter with 

 a steam-jacket. Mr. W. E. Jensen, on the other hand, 

 employs a spiral steam pipe, which he places inside the 

 wort cylinder. 



Somewhat different from the above is the pure culture 

 apparatus devised by Louis Marx, which, however, is so 

 constructed as to furnish only sufficient yeast for I hecto- 

 liter of wort. Several other forms were subsequently 



