440 On the Cultivation of the Vine } 
thing that can pave the way for acetous decomposition 
Hence the practice of putting a little sugar into the bottle 
to preserve the wine without alteration ; and hence the 
very general method of baking a part of the must at a 
slow and moderate heat, and of mixing some of it in the 
casks intended for embarkation. In some places of Spain 
and Italy all the must is baked ; and Bellon says that the 
wines of Crete would not keep at sea unless the precaution 
were taken to boil them. 
3d, The least spiritous wines are those which soonest 
become sour. We know, by experience, that when the 
season is rainy, if the grapes be little saccharine, which 
consequently give little alcohol, the wines readily turn 
Sour. The weak wines of the north become sour with 
great ease; while the strong, generous, spiritous wines ob- 
stinately resist acidity. 
It is however no less true, that the most spiritous wines 
furnish the strongest vinegar, though their acetification is 
more difficult, because alcohol is necessary to the forma 
tion of vinegar. 
3d, Wine perfectly free from all extractive matter, ei 
ther in consequence of its being deposited naturally by 
time or by clarification, is not susceptible of turning sour. 
I have exposed old wine in uncorked bottles to the ardour 
of the sun of July and August for more than forty days 
without the wine losing its quality ; only the colouring 
principle was constantly precipitated under the form of a 
membrane, which covered the bottom of the bottle. The 
same wine in which I infused vine-leaves, became sour 
in a few days. It is known that old wines, well purified, 
do not turn sour. 
4th, Wine does not acidify, or become sour, but when 
in contact with the air : atmospheric air mixed with wine 
is a real leaven of acidity. When wine grows fiat (se 
jjousse) it suffers to escape, or exhales, the gas it con- 
tains, and the external air then enters to assume its place. 
