AIR AN\ WATER FOR MICRO-ORGANISMS. m 



which are mainly of practical interest, belong the investiga- 

 tions of the micro-organisms which occur in brewers' "grains? 

 and in the air of the different portions of a brewery. 



As is known, "grains" contain numerous bacteria which 

 give rise to acid fermentations which are readily noticeable 

 by the odour produced. Should these bacteria be carried 

 into the air with the vapours arising from the grains, the 

 presence of the latter in the brewery yards would become 

 very dangerous. It is, therefore, quite natural that these 

 vapours have always been regarded with mistrust. Experi- 

 ments which I made at Mr. Kogsbolle's suggestion showed, 

 however, that these vapours did not carry away any bacteria. 

 If, on the other hand, the grains are allowed to become so 

 dry that the wind can blow them about as dust, they become 

 highly dangerous. As a rule, however, they are left for so 

 short a time that the whole mass remains moist, and danger 

 only occurs when the main bulk is removed, and small 

 quantities are left behind in the yard in thin layers. If 

 these are not carefully swept up and removed, they may 

 give rise to bacterial diseases.* 



A point of practical interest is shown especially in the dif- 

 ferent analytical results obtained at the same time, but in 

 different parts of the Old Carlsberg brewery. The atmosphere 

 in the fermenting room was found to be the purest. This 

 is due not only to the strict order which is always maintained, 



* I must not omit to call attention to the great danger in the drying machines 

 for grains which have been employed in recent years, especially in Germany. In 

 cases where I had the opportunity of examining grains dried in this manner, it 

 was found that the micro-organisms which they contained were by no means 

 killed, and this was especially noticeable in the case of the bacteria. If brewers 

 had studied with more attention than they have done my investigations on 

 grains in the brewery yards referred to above, they would certainly have shown 

 more hesitation than has often been the case before fitting up a drying machine 

 in such a manner that coolers and fermenting rooms are liable to become daily 

 infected by the dust teeming with bacteria which such a machine will produce. 

 In drying the grains, they are brought into the very condition in which they are 

 highly dangerous for the fermentations in the brewery. The brewer ought to 

 take all this into account when he is considering the question of putting up a 

 grains drying machine. 



