J. Nicklés on Changes in Wine. 251 
Although this acid may arise from fermentation of bitartrate 
of potassa, it has never, for a wonder, been found in wine which 
has lost its tartaric acid by means of adulteration. This fact 
confirms the observation, made long since in the practice of wine 
making, viz: that when the wine became changed in this man- 
her, all the crude tartar which had settled at the bottom of the 
casks disappeared little by little, an observation which confirms 
this other fact demonstrated by chemistry, to wit, that “changed 
Wine” contains more potassa than is found in normal wine. This 
is evidently due to bitartrate of potassa originally deposited in 
the bottom of the cask, which by redissolving and fermentation 
has furnished this excess of potassa now dissolved by the aid of 
the lactic acid and of the butyro-acetic acid produced during 
fermentation. : 
_ The “ turning” of wine which is characterized by the designa- 
hon changed wine (vin tourné), and which follows when the wine 
becomes bitter, consists essentially in a transformation of sugar 
into lactic acid, and tartaric acid into an acid containing the ele- 
ments of acetic and butyric acids, that is to say of butyro-acetic 
acid. Under the influence of this change the metamorphism of 
tartaric acid takes place not only when it is free and in solution, 
uteven when it is combined with potassa and is deposited at 
tne bottom of the cask in the condition of an iasoluble bitar- 
e: 
* The notation of Gerhardt shows clearly the difference hetween the two acids 
called propionic and butyro-acetic, Take for example the salt of baryta, the erys- 
talline form of which is identical for the two acids (Rammelsberg, Arystallograph- 
teche Chemie, ii, p. 161). ‘ 
e €,1,6 
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pine coment —oereentiny 
Propionate of baryta. Butyro-acetate of baryta. : 
To obtain the but etic acid, it is onl to pass a solution of acetate 
yro-acetic acid, it is only necessary 188 A 
and butyrate into a retort containing hot and dilute sulphuric acid, and to condense 
i 4 Convenient vessel the vapors which are disengaged. The condensed liquid ae 
tains an acid which being neutralized by baryta gives beautiful flat tees ian 
rytas’ er 
In this ease the t 
Combines to form the butyro-acetic acid in question. 
