852 
On the Cultivation of the Vine , 
even be converted into sugar : but the present is not the 
moment for discussing this important point. 
Grapes, then, may be very sweet and very agreeable to 
the taste, yet produce very bad wine : because sugar may 
exist only in very small quantity in grapes which to ap- 
pearance are highly saccharine. This is the reason why 
grapes exceedingly sweet to the taste do not always fur-* 
nish the most spiritous wines. In a word, a very little 
practice is sufficient to enable us to distinguish the really 
saccharine savour from the sweet taste which some 
grapes possess. Thus the mouth habituated to taste the 
highly saccharine grapes of the south, will not confound 
with them the chasselas , though very sweet, of Fontaine- 
bleau. 
We ought therefore to consider sugar as the principle 
which gives rise to the formation of alcohol by its decom- 
position, and sweet and saccharine bodies as the real leaven 
of spiritous fermentation. That must, then, may be pro- 
per for undergoing a good fermentation, it ought to con- 
tain these two principles in proper proportions : sugar 
alone does not ferment, or at least the fermentation of it 
is slow and incomplete. Pure mucilage does not furnish 
alcohol ; it is only to the union of these two substances 
that we are indebted for good spiritous fermentation.^ 
&d, Very aqueous must, as well as too thick must, ex- 
periences fermentation with difficulty. A proper degree 
of fluidity, then, is necessary to obtain good fermenta- 
tion ; and this is presented by the expressed juice of 
grapes which have come to perfect maturity. 
When the must is very aqueous the fermentation is 
slow and difficult, and the wine arising from it is weak, 
and very susceptible of decomposition. In this case the 
* There are some mucous bodies capable of undergoing spiritous fermenta- 
tion ; but it is probable that these mucous bodies contain sugar 3 which is more 
difficult to be extracted in proportion as the quantity is less. 
