THE LOSS OF COLOUR IN WINE 239 



174. The Loss of Colour (Umschlagen, Brechen) in Wine 



was first examined chemically by G. MULDER (II.) in 1855. Of this complaint, 

 which is known in France as vin taurne, and in Italy as vino girato, he gives the 

 following explanation : " This alteration of wine consists in a decomposition 

 of the tartaric acid, but how this decomposition is induced is unknown. The 

 cream of tartar is converted into potassium carbonate, whereby the colour of red 

 wine is altered and becomes brown. The decomposition begins at the bottom of 

 the cask, and is hence undoubtedly a result of the decomposition of the organic 

 matter of wine-yeast, which contains a substance acting destructively on the 

 tartaric acid, and, in co-operation with air, oxidising it to carbon dioxide and 

 water. As the malady progresses, the alcohol is converted into acetic acid, and 

 a putrefactive fermentation ensues." The commencement of this malady, which 

 appears more frequently in red wines than in white ones, manifests itself by a 

 slight evolution of carbon dioxide, which preliminary symptom is known in 

 practice as " boiling away " (versieden). Tartaric acid is not the only substance 

 eliminated, glycerin also according to the researches of P. CARLES (I.) being 

 slowly decomposed. Simultaneously, the amount of volatile acids increases to an 

 unusual extent (up to 4 grams per litre), a fact observed by SCHULTZ (I.), and 

 afterwards confirmed by J. MACAGNO (I.). 



Ten years after Mulder's observations, PASTEUR (XII.) undertook the task of 

 discovering the cause of this malady and proving that here also the activity of a 

 still unknown micro-organism was in question. He showed that in wines 

 affected with this complaint bacteria are always detectable in large numbers, 

 their length being 3-5 /*, with a breadth of 1-1.5 V- Greater probability was 

 imparted to this assumption by the observation made by SCHULTZ (I.), who, in 

 1877, succeeded in artificially imparting the malady to sound wine by inoculating 

 it with a small portion of a wine already infected. A closer study of the 

 organism could not at that time be made, owing to the lack of methods of pure 

 culture, a defect that, in this connection, was first overcome by E. KRAMER (I.) 

 with the organisms from a number of samples of Styrian and Croatian wines 

 affected with loss of colour. This malady, as is well known, is exceedingly 

 prevalent in southern countries, and causes great loss to the agricultural interest 

 every year. Kramer examined nine various species, all aerobic and liquefying 

 gelatin. The first seven of them he named Bacillus saprogenes vini I. VII., and 

 the other two Micrococcus saprogenes vini I. and II. Details and experiments 

 to prove whether these species are capable of producing loss of colour in sound 

 wines are still wanting, and consequently the Schizomycetes in question possess a 

 merely morphological interest. The actively motile Bacillus saprogenes vini /., 

 which is found in nearly every sample examined, is probably identical with 

 Pasteur's " Bacillus du vin tourne." It attains a breadth of i p. and a length of 

 2.5-6 n ; and bands composed of two or three cells are not rare. Bacillus sapr. 

 v. III. and VI. form endospores, and the cells of Micrococcus saprogenes vini II. 

 have a diameter of 1-1.4 /* A pure culture of a bacillus, which, however, was 

 recognised as innocuous, was obtained, from Italian wine suffering from loss of 

 colour, by J. GALEAZZI (I.) in 1894. 



These remarks sum up all that has hitherto been discovered by fermentation 

 physiologists respecting the loss of colour in wines. Consequently, knowledge of 

 the subject is still only in a very early stage, and we can only hope that future 

 researches will succeed in affording us f urther^enlightenment. This wine malady 

 is so diversified in its mode of development and so changeable in its course, that 

 we are obliged to ascribe it to a very fine example of metabiosis, i.e. that a single 

 bacterial species is insufficent to occasion the complaint, the successive action of 



