248 LACTIC ACID BACTERIA IN DISTILLING, ETC. 



ing 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 intro- 

 duced 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 souring 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 mis- 

 chance (unskilfulness 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. Morphological differences are also apparent at the first 

 glance, the cells of the distillery-bacillus being long, almost in- 

 variably more than 2.5 /x, 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 satis- 

 factory yeast-mash prepared by the old souring method in the 

 Lietzen Distillery (in the Mark Brandenburg), and received the 

 name of Bacillus acidificans longissimus. 



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 fermentation is 

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

 decomposing the calcium lactate formed. G. JACQUEMIN (I.) pro- 

 posed a similar method, but gave no precise information concerning 

 the nature of the ferment, and it is therefore uncertain whether 



