394 



The following table gives the composition of fresh grape must 

 and of the resulting fermented wine : 



Must. 



Wine. 



Water 



A Ibuminoid matters 



10 



73-86 



Glucose (chiefly dextrose) 12-24 



Gum 



Vegetable mucus 



Colouring matters (traces 



only) 



Tannin (traces) 

 Malic acid (in bad seasons) 



Patassium hydrogen tar- 

 trate 



Calcium tartrate 

 Other salts of 



matters 

 Mineral matters 



organic 



Water 



Residues of albuminoid 



matters 



f Glucose chiefly laevulose 

 | Alcohol ...... ... 



j Glycerine ... ... .:'. 



1 Succinic acid 



Acetic acid 

 ^Ethers 

 Gum 



Colouring matters 



Tannin 



Malic acid (in bad seasons) 

 f Tartaric acid 

 j Potassium hydrogen tar- 

 1 trate 



I^Calcium tartrate 

 Other salts of organic 



matter 

 Mineral matters 



6-14 

 O'o-l-o 



Total dry 



residue 



1065-1107 

 14-27 



Sp.gr 



Total residue 



.. -991--996 



INGREDIENTS OF MUST. 

 It is thus seen that grape must is a complex liquid. 



Water stands foremost at the head of the list as regards 

 quantity. In must of average composition it enters for about three- 

 quarters to eight-tenths of its weight. It acts as a vehicle of the 

 other constituents of must, diluting them to the required degree, 

 and bringing them all intimately together. 



Sugar, for instance, produces alcohol in fermenting, but in 

 order to ferment it must be considerably diluted, as, if too much 

 concentrated, it acts on the reverse as an anti-ferment, as is illustrated 

 in the case of fruits preserved in syrup. No liquid will ferment that 

 contains more than half its weight of sugar. 



Sugar. Next to water, sugar is the ingredient found in largest 

 proportions in the grape mash. It enters for about one-fifth to a 

 quarter of its weight, and sometimes more, running up in dry 

 seasons, and in over-ripe grapes, to nearly a third of the weight of 

 the must. 



That sugar is of a peculiar kind called "glucose," and consists 

 of a mixture, in about equal proportions, of grape and fruit-sugar, 

 known to chemists under the names of " dextrose " and " laevulose." 



