429 
The reading of the tests taken during vintage, duly recorded 
in a register, will supply valuable information respecting the 
character of the must of grapes grown from different varieties on 
different soils in different districts, and will permit of interesting 
comparisons being drawn with the must of previous years. 
Chemical Test—As already seen, the empirical as well as the 
physical means we have of ascertaining the richness of grape must 
is in practice found sufficiently correct, although not absolutely 
so. It is to laboratory tests we must rely for an exact determina- 
tion of the contents of a must in either sugar or acids, and as these 
tests are not readily made by the majority of wine makers, I re- 
frain from referring to them at length. 
Acipiry in WINE. 
In hot countries particularly, ripe grapes very often lack some- 
what in acidity, and it is not unlawful but even advisable to bring 
this acidity up to what it should be by the addition of tartaric acid. 
This ensures a healthy fermentation when that other important 
question of temperature is carefully regulated. The more natural 
acidity in a grape must, the greater difficulty ferments other than 
alcoholic will find in developing. Experience shows that 7 to 10 
grammes of tartaric acid per litre (.7 to 1 per cent.) will aid in this 
respect. If it is considered necessary to add tartaric acid to a 
wine, it should be done, as already explained, before and not after 
fermentation, or else a harsh wine will result which will set the 
teeth on edge. For that purpose the quantity of crystals of tartaric 
acid to be added to a given vat is distributed by hand over the 
grapes in the crusher, or else it is put in a bucket of must, dis- 
solved, and added gradually to the vat in process of being filled 
with freshly crushed grapes. 
The measurement of the acidity of the must is expeditiously 
done by means of a cheap apparatus called “acidimeter” but, on 
account of the small quantities of liquid operated on, any error in 
measurement is greatly increased when caleulated to one vatting. 
In wine analysis the acidity is usually expressed in terms of 
sulphurie acid. This is a conventional arrangement, but when deal- 
ing with musts it is preferable to express the acidity as tartaric 
acid. To ealeulate the acidity as tartaric acid, the figures express- 
ing it as sulphuric acid must be multiplied by 1.53 (page 422). 
The acidification of the vintage is so rarely necessary in Aus- 
tralia that it is not practised. 
