190 LACTIC ACID BACTERIA IN DISTILLING, ETC. 



We are indebted to Morawsky for the first improvement on this point. 

 Instead of waiting for the yeast-mash to become infected spontaneously by lactic 

 acid bacteria, as in the ordinary course, he proposed to set aside about one-tenth 

 of the soured mash before applying heat, and to add this mother-acid to the next 

 day's mash as soon as the latter has been saccharified and cooled down to 50 C. 

 This modification, although constituting a valuable improvement on the older 

 method when once operations are in full swing, nevertheless does not positively 

 guarantee good souring ; and its deficiencies are most apparent at a time when 

 help is most essential, viz., at the commencement of a new season. During the 

 first few days after work is resumed, it often becomes apparent from the odour 

 permeating the yeast-room that the souring is not progressing satisfactorily, but 

 that the mash is rich in butyric acid. This is due to the fact that the lactic acid 

 bacteria in the distillery have more or less completely perished during the 

 summer while the works were shut down. 



To completely overcome the difficulty, nothing must be left to chance, and 

 the souring must be properly regulated by inoculating the sterilised and cooled 

 yeast-mash with a sufficiency of a pure culture of lactic acid bacteria. Such a 

 method was first introduced by the author at the Hohenheim Distillery, where it 

 was tried with great success. The further treatment of this artificially inoculated 

 mash differs in no wise from the procedure already described, i.e. when the sour- 

 ing is completed the mother-acid is removed, the bulk of the mash is heated up 

 to 70 C., then cooled, and pitched with the prepared mother-yeast. Next day 

 a portion is taken to serve as mother-yeast for a succeeding mash, and the 

 remainder is added to the principal mash. If, through any mischance (unskil- 

 fulness or carelessness on the part of the distiller), the souring of a given mash 

 proves defective, then no mother-acid is reserved from it, but a pure culture is 

 used for pitching the yeast-mash on the following day. 



Although the species of bacterium now in question shares with the milk-souring 

 bacteria the property of decomposing sugar and forming lactic acid, it nevertheless 

 differs from them in more than one respect. For example, the various species of 

 the lactic acid bacteria in milk, so far as they have been examined, are incapable 

 of developing in mashes and worts under the conditions prescribed above. Mor- 

 phological differences are also apparent at the first glance, the cells of the 

 distillery-bacillus being long, almost invariably more than 2.5 j*, and very 

 frequently attaining ten times this length, whilst the breadth remains uniformly 

 about i p. This microbe was isolated by the author in 1896 from a satisfactory 

 yeast-mash prepared by the old souring method in the Lietzen Distillery (in the 

 Mark Brandenburg), and received the name of Bacillus acidificans longissimits. 



On account of its powerful fermentative activity, this bacillus can also be 

 utilised to advantage in the preparation of lactic acid for technical purposes. The 

 dyeing and cloth -printing industries in particular require continually increasing 

 quantities of this acid, the preparation of which by purely chemical means is at 

 present a rather costly process, and can be more cheaply effected by means of 

 lactic acid bacteria. For this purpose a sterilised unhopped beer wort, rich in 

 maltose and qualified with a sufficient addition of calcium carbonate, is inoculated 

 with a pure culture of the bacillus and maintained at 50 C. When the fermen- 

 tation is ended the liquid is concentrated, and the lactic acid separated by 

 decomposing the calcium lactate formed. G. JACQUEMIN (I.) proposed a similar 

 method, but gave no precise information concerning the nature of the ferment, 

 and it is therefore uncertain whether the organism is allied to, or identical with, 

 the above-mentioned bacillus. The method described by E. DELACROIX (I.) 

 utilises, by a similar course of treatment, the sweet whey formed as a waste 

 product in dairies. 



