272 PROCEEDINGS OF SECTION B. 
SECTION B. 
CHEMISTRY AND MINERALOGY. 
No. 1—ON THE COLOURING MATTERS OF WINES. 
M. Biunno (Licenziato in Scienze), New South Wales Depart- 
ment of Agriculture. 
(Read, Friday, January 7, 1898.) 
[ Abstract. | 
Tue author refers to and discusses recent investigations in this 
subject by M. Rosensthiel and Gautier. 
It is well known that the juice, even of red grapes, is nearly 
always colourless. This was attributed to the insolubility of the 
colouring matter in water. Rosensthiel’s experiments have how- 
ever shown that at a temperature between 50° and 70° Centigrade 
the unfermented juice is capable of dissolving colouring matter. 
These colouring matters are very unstable and are attacked by 
nearly all metals. At such a temperature air is a remarkably 
powerful decolouriser, and is capable of rendering the red colouring 
matter insoluble in alcohol. 
If unbroken grapes be heated to 50° Centigrade in a hermetically 
closed vessel, the wine produced in crushing and fermenting these 
grapes will not be red. 
It is therefore necessary to exclude the air if the colouring 
matters are to be kept unaltered. 
These experiments are of practical importance, because the treat- 
ment above described not only renders the colouring matters 
soluble and stable in the must, but destroys the Saccharomyces, 
while germs of mould and bacteria are hindered from developing. 
It would from this appear quite possible to destroy the natural 
ferments by pasteurizing must and skins together at 50° centigrade, 
such treatment being without effect upon the colour and taste of 
the resulting wine. 
Rosensthiel recommends heating three times to 50° when all 
natural ferments are destroyed and fermentation may be brought 
about by means of selected yeasts. 
