358 
POPULAE SCIENCE EEVIEW. 
necessary to check it altogether by the addition of spirit, thus 
bringing the alcoholic strength above the limit within which 
fermentation can take place. Such wines, therefore, retain part 
of the sugar* unaltered, as well as of the albuminous compounds; 
moreover, sufficient time not having been allowed for that 
gradual and slow action of the atmospheric oxygen necessary for 
the production of the odoriferous principles, these wines when 
young are almost devoid of the bouquet that distinguishes the 
■wines of more temperate climates. 
Unfortunately little or nothing is known concerning the tem- 
perature most suitable for fermentation, with a view to bringing 
all the good qualities of a wine to perfection, the temperature 
being left practically to the chances of weather and climate. It 
would seem, however, that a temperature approaching the lower 
limit at which fermentation is possible yields the most fragrant 
and the most durable -wine; and there is little doubt that if the 
wine producers in Spain and Portugal allowed their must to 
ferment in cellars, the temperature of which was artificially 
kept low, by being in connection with ice pits,f a wine might be 
obtained which would keep without the addition of spirit, and 
would then really be a natural Sherry or Port, and at the same 
time be an excellent wine. On the Ehine, on the other hand, the 
temperature during vintage is frequently too low to allow of the 
thorough fermentation of a rich must before the cold of winter 
checks it entirely ; and such wines have to be kept sometimes 
five or even more years in a cold cellar before they are fit for 
bottling. During the whole of this time a slow chemical 
action proceeds, by reason of which the sugar gradually disap- 
pears, and the albuminous matters are removed either as ferment, 
or by oxydation as above described. If in these cases the first 
fermentation were judiciously stimulated by means of a some- 
what higher temperature, the time necessary for this after 
fermentation might no doubt be considerably shortened. But 
to return to our must. When the first fermentation is com- 
pleted, the greater part of the sugar has disappeared, and in its 
place alcohol, glycerine, and succinic acid are chiefly found ; 100 
parts of sugar yielding about 
48*5 parts of alcohol 
iy glycerine 
0*67 „ succinic acid 
46*4 ,, carbonic acid 
which latter escapes, however, almost completely. 
. * The sugar in the must is frequently increased by evaporating a part, 
and then remixing this with the rest. 
t In many large breweries in Germany the stock of beer is kept during 
the hot season in vaults which are in connection with an ice cellar, by 
