THE BITTERING OF WINE. 405 



Respecting the cause of this incurable disease of wine, nothing 

 reliable can as yet be stated. PASTEUR (XVI.) attributed it to the 

 activity of a rod-shaped fission fungus, without, however, being 

 able to throw any further light on the matter. The bacteria found 

 in large numbers in bitter wine are for the most part covered with 

 flakes and fragments of the precipitated brownish-red colouring 

 matter, and hence very often assume remarkable shapes. They 

 may be freed from these incrustations by the addition of a droplet 

 of a solvent mixture of alcohol and tartaric acid to the preparation. 

 R. ADERHOLD (I.) unsuccessfully attempted to prepare pure cul- 

 tures of the organism suspected of causing this malady, but PER- 

 RONCITO and MAGGIORA (I.) were able to artificially induce the 

 complaint in sound wines by inoculating them with a bouillon 

 culture of microbes discovered in bitter wine ; the infection, how- 

 ever, succeeding only in such samples as contained less than 8.5 

 per cent, of alcohol. The attempts at inoculation made by E. 

 Kramer with a bittered white wine from the province of Kiisten- 

 land (Austria) did not prove satisfactory. At present, uncertainty 

 prevails not only with regard to the organism causing this com- 

 plaint and the external conditions influencing its development, but 

 also as to the nature of the bitter principle itself. The opinion 

 expressed by Mulder, that citric ether is in question, was refuted 

 by C. NEUBAUER (I.), who proved that this (still uninvestigated) 

 bitter principle is a compound that is not volatilised by boiling the 

 wine. From experiments made by J. BERSCH (I.), it is permissible 

 to conclude that the tannin present is decomposed and consumed by 

 the organisms here in question. This observation would suffice to 

 explain the fact mentioned at the commencement of this paragraph, 

 that bittering is almost exclusively confined to red wines, these 

 containing, as is well known, a somewhat large amount of tannin 

 absorbed from the skins and kernels of the grape during the 

 primary fermentation. 



It may be useful to casually mention, in conclusion, that the 

 bittering of alcoholic beverages, beer in particular, may also be 

 occasioned by higher fungi (yeasts). Fuller particulars will be 

 found in a subsequent chapter in the second volume, dealing with 

 Saccharomyces Pastorianus, and to which the reader is hereby 

 referred. 



END OF VOL. I. 



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 Edinburgh & London 



