238 Jgricnlfural Gazette of N.SJF. [J/^rrr. 2, 190«. 



All otlicr conditions hciiiif e(|ual tlio yeast works Ix^ttor in a <ii';i]>c juice, 

 say, wit!) 8 parts of ui'ape acids for cNcry IJIUO parts of nuist tlian in the 

 same i^rape juice with only 6 pai-ts per 1,000. 



All or nearlv all viirnerons nuist he under llir impn'^sicm thai in ura])e 

 picking all unripe and second crop hunches, w liicli arc ^our. ^hoidd he carcf iplv 

 avoided. This is another of those pi-cjiidices which I am det rniiiiicd to lii^dit- 

 against. The sourness of the second cro}) of grapes is due to nothing else hut 

 to a deficiency of grape sugar and to an excess of acids. Then there you have 

 th(> most natural corrective of the bulk of your crop, which is too sweet and 

 contains little acidity. When this couiitry will teem with millions, and 

 wine growing will he carried on on evei\' patch that is unsuitable for an\ thing 

 else, and the sides of iMount Kosciusko will he terraced up to 3,000 feet, and 

 planted with vines, then tin; Government Viticulturist will tell the wine 

 growers of the mountain that they nuist avoid picking uji umijie grapes. But 

 now in the Albury district, I say pvit them altogether, your wine will be all the 

 better. It is much easier to do this than to make an earlier vintage such as i.s 

 often advised in hot countries. An early \intage would give grapes that are 

 not over ripe, but how can a vigneron decide l)y sim])ly tasting the grapes, 

 and judge of their acidity, and say whether it is 7, S, oi- 9 parts per 1,000 ? 

 Were he skilled in chemical work, he could take daily samples of grapes and 

 test them, but, even if he could do that, there is nothing so misleading as the 

 tests on samples of grapes, which are made hy four or live liunches jiicked 

 on different j^oints of the vineyard, representing anything hut tie- hulk. 

 Why even the ])osition of the berries on the same bunch will make adiil'eience,. 

 and those on the shoulder are usually less acid than those on the point of the 

 bunch. Besides, when grapes are well on the way of i-i))ening, every day 

 makes a great difference ; therefore the last to be i)icked would always be over 

 ripe for wine-making ))urpose, and in most cases a vigneron would begin 

 picking grajjes when they contain, say, '.) jiarts of acid in l.OdO parts of must, 

 and the grapes picked last would finally contain much less. 



Now as to the Temperature. 



Fermentation is a complex phenomenon. It is physiological in so far as 

 a live organism, viz., the yeast is concerned, hut the yeast exudes a substance 

 called diastase, which acts chemically on the grape sugar and transforms it 

 into alcohol, carbonic acid, i^'c, as ahoxe stat(nl. JM'rmentation, therefore, is 

 a chemical phenomenon as well, and like in all such phenonu'iia there is 

 always loss or production of heat. Fermentation, however, always provides 

 heat; every particle of sugar that is S|>lit up in the various bodies already 

 enumerated juoduces heat. You niav easilv imagine the amount of lieat 

 generated by o cwt. of gi'ape sugar which is contained in a ton of grapes with 

 25 per centum of that ingredient. 



Tf the grapes come in hot, and after being crushed they mark 75' Fahr., 

 you will find that such temperature will steadily rise, and after foi-ty-eight 

 hours or so the li(piid will be so hot as to disturb the normal conditions of 

 life of the leaven, that is, of the yeast. 



