140 Agricultural Gazette of N.S.W. \_Fcb. 3, 1908. 



On the Chemical Composition of some 

 Australian Wines. 



M. BLUNNO, Goveriimeiil Viticultuiist, and L. A. MUSSO, Assistant to the 



Viticuh iiial lirancli. 



The tables l)elow ivfer to the aiialyticsil data of some of the .Vusti'aliaii wines 

 analysed under the AN'ine Adulteration Act, IDOl', with the view of aseertain- 

 ins: whether thev had been submitted to aiiv illicit treatment. 



We are j^dad to say that the statement so often made of Australian wines, 

 or of New South AVales wines at any rate, being adulterated, has little if any 

 foundation at all. in so far in one case only we found one sample of sherry, 

 one of port, and another of sweet red, all sold by the same South Australian 

 tirm, which contained an unchie amount of sodium chloride, \iz., common salt, 

 for which offence the firm in ([uestion was lined. 



Also in four samples of sweet wines recently analysed and not iiuluded in 

 these tables we found an excess of alcohol, ranging from 1 to .5 jjer cent, of proof 

 spirit above the limit of 35 per centum prescribed by the Act for sweet wines. 



It was not thought opportune to lay any infoi-mation against the merchants 

 concerned as it Avas obvious that the slight o\er-fortification was due to a 

 mistake of calculation on the part of the wine-growci' oi' of the merchant, who 

 generally do not possess the knowledge oi- the ajiparatus for an exact estimation 

 of the alcoholic strength of their wines and of the wine-spirit used for fortify- 

 ing. That there couid be no malice in it is evid(Mit when considei ing that wine- 

 spirit is not a cheap substance, and, therefoi'e, no undue advantage would be 

 gained by anyone to increase the alcoholic strength of wine, which would also 

 raise the cost of production at a time when com[)etition is lather keen. 



It is generally said that Australian wines are too acid, and the expression 

 is as co]lo({uial as it is misleading. There are two kinds of acidity in wunes, 

 one which is called fixed acidity, and is that wlii(di is naturally found in 

 grapes, consisting of malic acid (apple acid), tartaric acid, and potassium 

 acid tartrate; the other acidity is volatile and forms during and after fer- 

 mentation of the grape juice. This volatile acidity is higher in wines the 

 fermentation of whidi has been neglected, oi" where the article is not kept 

 with all the diligence and skill such as the keeping of wines in casks or in 

 bottles recjuire. Volatile acidity in wines is mainly due to acetic acid ; with 

 it smaller ])roportions are to be found of formic, propionic, butyric, valeric, 

 caproic, and acids which are responsible for the nasty smell and taste of 

 souie wines. Volatile acids in wines are always the eil'ect of secoiuhiry 

 fei'mentatioiis which take place while the alcoholic fermentation is iu process 

 or after, and natui'allv implies the presence and growth of bacterial life. 



Not even the best of the world s wines are exem])t from traces of volatile 

 acidity ; such traces are howcvei- so negligible that the trained palate, wdiitdi 

 is the finest analyser, fails to detejt because the liompu't of said wines is so 

 marked as to ol)literate any contrasting crgaiiolc]itic sensation. It is when 



