36 
TOPULAR SCIENCE REVIEW. 
removal, such changes only occur in it as are brought about by 
fermentation itself; such as, for example, the conversion of the 
sugar into alcohol, &c., the solution of colouring matter, pre- 
cipitation of tartar, &c. &c. The wine, moreover, having once 
thoroughly fermented, is not very liable to further change in 
that direction, and is therefore wholesome and of excellent 
keeping quality. In fortified wine, on the other hand, fer- 
mentation has not been allowed to run its regular course, but 
has been checked prematurely by the addition of spirit, by 
which the strength of the wine is brought above the limit 
within which, as we have learned, vinous fermentation is pos- 
sible. The wine, therefore, although of good keeping quality 
as long as its strength is unimpaired, is liable to ferment when- 
ever the preserving power of the spirit added may be destroyed 
by dilution, as, for example, when the wine is drunk.* It is 
on this account less wholesome than the pure wine. The con- 
centration of the wine also is lessened by the addition of the 
spirit, in consequence of which it contains relatively less con- 
stituents of the grape than the natural wine. The fortified 
wine certainly often contains no inconsiderable amount of sugar 
which has been preserved from fermentation, and this induces 
the belief that greater concentration exists ; but this sugar has 
only been preserved at the cost of a great addition of spirit, 
whereby all the other constituents have been diluted.f This 
sugar, moreover, if required, could be obtained much more 
cheaply as cane sugar. A bottle of port wine with 4% of sugar 
(and this is a sweet port) contains about 1^ of sugar, of the 
value of one-third of a penny. 
* Medical men will probably find in this an explanation of the fact that 
even good fortified wines are liable to produce flatulency and dyspepsia in 
persons with weak digestion. The wine is drunk, either already diluted 
with water, or is subsequently diluted by the gastric juice ; the protecting 
power of the spirit is destroyed, and fermentation and consequent acidity are 
the necessary result. 
t An example will, perhaps, make the case more clear. Supposing a 
mud from which port is to be made to contain 28° 0 of sugar — and this would 
be a very good must — it would be capable of producing a wine having a 
strength of about 13%. If now 4% of sugar are to be retained in the forti- 
fied wine, the strength produced by fermentation will barely reach 10%, 
and, as the wine has to be brought up to say 19% (42 degrees proof spirit), 
about 30 bottles of proof spirit have to be added to every 100 bottles of 
wine. All the vinous qualities before contained in 100 bottles are now dis- 
tributed through 130 bottles, or one bottle of the fortified wine contains only 
about three-fourths of a bottle of real wine. The dilution will be somewhat 
loss if stronger spirit is employed, but the general fact will remain the same. 
If, as is frequently the case, grain spirit or even potato spirit is used for ad- 
mixture, dilution is not the only drawback, inasmuch as substances quite 
foreign to the genuine wine are, in that case, introduced in addition. 
