THE LACTIC ACIDIFICATION OF WINE 193 



the succeeding mash. The residual four-fifths are incorporated with the fresh, 

 saccharified principal mash, previously mixed with enough hydrofluoric acid (or 

 ammonium fluoride) to make the (percentage) content thereof equal to one-half 

 that of the yeast-mash. This proportion has been found to be suificient ; and 

 since high patent royalties have to be paid to the " Societe Generate de Maltose 

 a Bruxelles," of which M. Effront is director for the use of hydrofluoric acid for 

 this purpose, the distiller will naturally avoid employing more than is absolutely 

 necessary. 



Although hydrofluoric acid undoubtedly affords a reliable means for com- 

 bating bacteria, and can be used with advantage to keep yeast free from these 

 objectionable organisms, the case is different when the purification of a yeast 

 from contaminating wild yeasts is in question. EFFJRONT (V.) prescribed a 

 method which he thought could effect this latter purpose, but the same was 

 shown by A. JORGENSEN and J. CH. HOLM to be unreliable. Some further 

 particulars on this point will be given in a suitable place in the second volume. 

 At present we will merely state that the hydrofluoric acid process in nowise 

 supersedes the employment of pure culture yeast ; on the contrary, the value of 

 such yeast has here been revealed in a new light. 



151. The Lactic Acidification ("Ziekendwerden ") of Wine. 



The souring of wine and beer is by no means a uniform phenomenon, but 

 may, on the contrary, appear in many forms. The most frequent is the vinegar 

 taint, i.e. a partial conversion of the alcohol into acetic acid by acetic acid 

 bacteria. Fuller particulars of this evil will be given in chapter xxxvii. The 

 subject of the present paragraph is the lactic; acid taint, i.e. the production of 

 acidity by lactic acid bacteria, and which is generally known in Germany as 

 " Ziekendwerden." This is a not infrequent malady, and usually makes its 

 appearance in company with other injurious changes. Even Pasteur classed it 

 along with the so-called turning or breaking of wine, and the expression " Vin 

 tourn6 " is still applied in France to both phenomena, other terms being " Vin 

 monte " and " Vin qui a la pousse." The course and characteristics of the 

 malady are as follows : It mostly attacks young vintages, occasionally appearing 

 even in the first year. The wine turns turbid, and the odour and flavour 

 gradually become irritating, like rancid butter. The turbidity increases by 

 degrees to such an extent that the wine has the appearance of diluted milk, this 

 white break passing over finally, in many instances, into the stage of black 

 break, the wine then being in the condition of a brown to inky black liquid. 

 Concurrently with this change of colour occurs a gradually increasing precipi- 

 tation of dark slimy masses a phenomenon characteristic of this malady. The 

 presence of lactic acid in " Vins tournes " was detected by A. BALLARD (I.) 

 in 1861. J. BERSCH (I.) examined four samples of broken ("zickender ") wine 

 for their acid-content, and obtained the subjoined results : 



The production of the two last-named acids was ascribed by PASTEUR (XII.) 

 in 1866 to the action of fission fungi. Experience shows that vintages poor in 



