no Journal of Agriculture. Victoria. [lo Feb.. 1911. 



advantage over the natural yeasts which find their way into the juice ia 

 the spore state. More reliance has been placed on this point than was 

 justified. 



In this connexion the use of sulphurous acid (see article on Sulphiting 

 in January Journal) constitutes a very considerable advance. Its antiseptic 

 action on the spontaneous organisms prevents their development, whilst 

 it does not hinder that of the added yeast, previously accustomed, in a 

 .separate culture, to life in its presence. Sulphiting has thus very power- 

 fully contributed to the 



Increase in the Use of Pure Veasts in France. 



That this is becoming more and more general is amply proved by the 

 increased attention the subject receives in French viticultural literature. 

 Even the advertisements show the increasing interest which is now being 

 taken in the question in France where numerous institutions now devote them- 

 selves to the propagation and sale of pure cultures of selected varieties of 

 yeast. There is also a decided tendency for the trader to pay a higher 

 piice for '" Levured ' wines. The extension of sulphiting and the better 

 understanding of the laws governing the development of yeast are respon- 

 sible for this marii^ed increase. The object of the present article is to 

 give some idea of the position the pure yeast question now occupies in 

 France, to sum up as briefly as possible the leading opinions held on the 

 subject, and to endeavour to explain some of the difficulties yet to be faced 

 in connexion with it, and which have been responsible for its slow spread. 



Though progress has been slow it is none the less sure. Professor 

 Astruc describes how numerous comparative tastings have proved wines 

 made with the aid of selected yeasts to he generally superior to those made 

 in the ordinary way. One of the causes responsible for its slow adoption 

 is that too much was expected from the new method at first. It was 

 thought that it was only necessary to ferment a common must with a yeast 

 derived from a celebrated vineyard in order to obtain a product resembling 

 closely the wine from which the ferment was derived. The bouquet was 

 at first thought to be largely due to the yeast, but it has proved itself to 

 be a very elusive quality and little permanent result has been obtained in 

 this direction. Disappointment of these first extravagant expectations 

 led to the neglect from which the method has only recently recovered. 



Reasonable Expectations. 



It is now abundantly proved that decided advantages are to be gained 

 from the use of culjtivated yeasts, especially in the following directions : — 



Increase in Alcoholic Strength. — This may amount to i or even 2 per 

 cent, proof. It is due to two causes, viz.. the use of a yeast of higher 

 fermental power ; in other words, one which can transform a larger quantity 

 of sugar for the production of a smaller weight of yeast substance, and 

 to the elimination of organisms which transform the sugar into other 

 substances than alcohol — what M. Astruc terms sugar eaters {Mangeurs de 

 Sucre), as opposed to ferments in the strict sense of the word.* 



Improved Condition. — Wines fermented with pure yeasts, as a rule, 

 clear themselves more rapidly than those resulting from spontaneous fer- 

 mentation. Marked differences are to be observed in the behaviour 

 of different varieties of yeast after the close of fermentation. Some possess 

 the property of uniting together into small masses, thus bringing about 



• The maximum production of alcohol possible would entail the transformation of 16.4 grammes of 

 Sugar per degree of alcohol (absolute by volume) and per litre. 



