421 
Components or Must. 
It is thus seen that grape must is a complex liquid. 
Water stands foremost at the head of the list as regards quan- 
tity. 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, diluting them to the required degree, and bring- 
ing them all intimately together. 
Sugar, for instance, produces alcohol in fermenting, but in 
vrder to ferment it must be considerably diluted, as, if too much 
concentracted, it acts on the reverse as an anti-ferment, as is illus- 
trated in the case of fruits preserved in syrups. No liquid will 
ferment that contains more than half its weight of sugar. 
Sugar.—Nest 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 
“leevulose.” 
The chief characteristic of glucose, or unerystallisable sugar, 
compared with cane-sugar, or “saccharose,” is that the former can 
ferment, whereas cane-sugar, in order to ferment, has previously 
to be turned into glucose. 
Another charcateristic is that while cane-sugar can be turned 
into glucose, this latter form of sugar has never yet been changed 
into erystallisable sugar. The invention of a process that would 
achieve this would be worth more than all the mines of this country 
put together. 
During the process of fermentation, “dextrose” is the first to 
be acted upon by the yeast; and if the wine is badly fermented, 
and remains sweetish, it is “levulose,” which is found to have re- 
mained unchanged. 
During the process of fermentation the constituents of glucose, 
properly diluted, are split up into substances differing from it, 
both in their physical and in their chemical properties, the products 
of fermentation being carbonic acid gas and alcohol, besides other 
bodies such as glycerine and succinic acid, which occur in small 
quantities, and which vary in some measure with the vat tempera- 
ture during fermentation: the glycerine giving mellowness to the 
wine, while the s*ccinic acid gives it that peculiar taste known as 
“vinosity.” 
Acids Besides these two important ingredients, viz., water 
and sugar, the must of the grape contains small proportions of 
acids, such as tartaric acid, which oceurs to a large extent in the 
vegetable kingdom; malic acid, or the acid found in apples; and 
tannic acid or “tannin”: and cream of tartar, which is an acid salt. 
