406 



Stalking, moreover, is effected by a mechanical tearing and 

 tossing about of the grape, which result in a thorough aeration of 

 the must, an operation which ensures a more active and healthy 

 fermentation, and reacts favourably on the quality of the wine. 



In the manufacture of white wine the same objections dis- 

 appear, as white wines should not be fermented on either skins or 

 stalks. 



For the easier pressing of the sweet juice out of the glutinous 

 pulp, however, the admixture of stalks are of great assistance, as 

 they prevent the solidification of the soft pulp. 



In that case, the stalking part of the machine should be 

 thrown out of gear and the whole bunch, stalk and all, mangled 

 between the rollers of the grape mill. If the type of machine does 

 not permit of that, the pulp and the stalks should either be mixed 

 together in the cage of the press, or else they should be superposed 

 in alternate layers, as the stalks will prevent the solidification of 

 the glutinous mass and keep it porous and open, thereby favouring 

 the escape of the juice when the pressure is applied. 



White wines fermented apart from skins and stalks are lighter 

 in colour ; it is true that the wine is at times slow in clearing, on 

 account of a deficiency of tannin which the pips and the stalks 

 failed to impart to it ; by pressing the stalks with the pulp this 

 deficiency is in some measure corrected. 



AERATION. The operation of running the grapes through the 

 stemmer and crusher, it has been noticed, results in a better aeration 

 of the must, as the bunches of grapes are vigorously tossed about 

 during that process, with the result that the skins burst, and, after 

 passing through the rollers, the berries are reduced to a state of a 

 pulp. 



Pasteur has demonstrated that one of the main factors in the 

 maturing of the wine is the oxygen, which is readily taken up by 

 its constituents and by them held in a state of loose chemical 

 combination, from which it is readily given up as required. A 

 phenomenon of a similar nature occurs in the case of the grape 

 juice ; under the influence of warmth and the oxygen absorbed by 

 the liquid, the process of maturation of the grape is consummated 

 inside the vat, and the must is thereby enriched by the full amount 

 of fermentable grape sugar it is capable of acquiring. 



Although the must absorbs much air during the operation of 

 crushing, it is often considered advisable to further aerate it previous 

 to setting it to ferment. 



The influence of aeration in quickening the starting of fermen- 

 tation is now well understood by the wine makers of the old world, 

 and various designs, as well as special appliances, are employed in 

 carrying out that process, both in the making of red and of white 



