54 WINE AND THE ART OF WINE TASTING. 



This malady occurs oftener in white than in red wines; in late years, 

 however, it has been found often in red wines on account of the unfavor- 

 able conditions for the grapes attaining a complete maturity, such, for 

 instance, as the damages done by insects, cryptogams, and bad weather. 

 It occurs easily, too, in red wines made from grapes grown on very 

 fertile soil rich in albuminoid substances. 



Very probably this deterioration is much more complex than is 

 usually supposed. 



Peligot was the first to establish the presence of a micro-organism, of 

 a bacterium. Pasteur, later, demonstrated that this bacterium has the 

 property of transforming the sugar that remains in the wine into a 

 mucilaginous or viscid substance.* 



Bechamp calls the active ferment of this process Micrococcus viscosus, 

 and the gum which is formed viscosio. 



Tannin and alcohol, in certain proportions, prevent the development 

 and action of this bacterium; the conclusion, therefore, is that wines 

 poor in alcohol and tannin, and containing sugar, are subject, especially 

 if white, to become " filant." This explains also the use of tannin, as 

 proposed by M. Frangois, of Chalons, to arrest or prevent this malady. 



Francois attributes this malady to a peculiar nitrogenous substance, 

 gliandin, a kind of glutin, which seems to have the property of being 

 precipitated by tannin. Nessler affirms, however, that we do not know 

 yet how the tannin acts. 



I have already remarked on the complex nature of the malady under 

 discussion. Usually it is held to be owing to a lack or deficiency of 

 tannin. This, however, is not invariably true, since Francisco Selmi 

 has found it in wine made from Lambrusca grapes, and therefore rich 

 in tannin. It seems that in this malady the tartaric acid also suffers 

 changes. Probably on account of these changes Bizzari proposes the 

 use of tartaric acid, 200 to 250 grammes per 100 gallons, as a cure or 

 preventive of the malady. 



*The bacterium of "La Graisse" put into a solution of sugar containing albuminoid 

 and mineral substances acts upon the sugar and transforms it into a kind of gum, man- 

 nite, water, and carbonic acid. Thus, 100 parts of cane sugar will give 50.09 parts of man- 

 nite, 43.5 of gum, besides water and carbonic acid. 



Monoyer proposed to account for this transformation by two chemical equations, the 

 first of which would give mannite and carbonic acid, the second gum and water, as 

 formed from the glucose. 



Schmidt-Mulheim is about of the same opinion, he believing that the viscous fermen- 

 tation consisted of two processes, the first of which gave mannite and carbonic acid, 

 and the second the viscid substance. 



Kramer has studied this ferment. He examined three wines afflicted by it, and besides 

 Saccharomyces ellipsoideus, Saccharomyces mycoderma, etc., he found an extremely minute 

 bacillus 2 to 6 // long, and .6 to .8 /J, thick. He failed to cultivate this bacillus on potato, 

 agar agar, etc., but by putting a little of the infected wine into a new (three months) 

 white sterilized wine and with 3 per cent of glucose, he found that the bacillus devel- 

 oped well and rendered the wine "filant," but only when the air was completely excluded 

 by covering the wine with a layer of oil. With access of air there was very little devel- 

 opment of the bacillus, and instead an increase of the other ferments of the wine. 

 Kramer has called this ferment Bacillus viscus vini. 



The peculiar kind of gum produced by the viscous fermentation of the sugar renders 

 the wine viscid and glutinous. In its properties it resembles dextrine more than it does 

 gum arabic. 



The viscid substance, according to Kramer, appears to be a product of assimilation of 

 the organism, whilst the carbonic acid and mannite, which are formed contemporane- 

 ously, are products of the fermentation; a constant proportion between the first and the 

 last substances does not exist. 



The bacillus multiplies very well in its own viscid product. 



forms a kind of glue. It has no acid reaction. 



