4i8 Ac'iDii \ Mj- wiNi:. 



whether the wine is sound or unsound. A bacteriological exam- 

 ination and tasting by a connoisseur should be added to the chemi- 

 cal determination of the volatile acidity of a wine. 



With regard to the \alue of fastiiuj, Mathieu (11) points out 

 that the volatile acids influence both the bouquet and the ta'^te of 

 a wine. He says further : 



A connoisseur can soon icll \vlutlRr a (lisoasocl wine suffers Ironi 

 an acetic fermentation, or " tourne " ( act-tic and propionic acid), or rancid- 

 ness (butyric acid). If the wine contains carlxm dioxide, the volatile acid 

 will seem more on tasting' that it is in realit\. Tliis is very noticeal)le 

 before and after imprei-natint; a wine wiih carl)on dioxide. On tastinii, 

 the impression obtained about the volatile acid dep>nd>- ri))on — 



( 1 ) The amount of volatile acid present ; 



(2) The nature of the volatile acids; 



(3) Certain other constituents of the wine, of whicli alcohol and 



saccharine substances tend to (Hminisli or cover it, whilst 

 the fixed acids and carbonic acid tend to cxa,a:gcrate it. 



Hence tasting alone is not sufficient. Chemical analysis alone Avill not 

 do ciilier. lloth coinl)incd must he used. Tasting will show: ia) Whether 

 the wine is perfectly sound: (/') whetlier its soundness is douhtful ; 

 (r) whetlier it lias decidedly gone wrong, .\nalysis will discover ;iny 

 deception under (a), decide (h), or conlirm (<). if a comparison is made 

 between the wine in question with sound wines of the same nature. // is 

 not possible to hiy doicii definite limits far llic roIcitHc acidity as a means 

 of dcterniiniir^ the soundness of all %i.'ines. (The italics are mine. — 

 A. ]. P.) In douhtful cases a comparison should he nvide with sound 

 wines of the same class. 



Wortmann (8) also points out how alcohol and stigar cover 

 the volatile acidity on tasting, hut differs from Mathieu, where he 

 ascribes a covering efifect to a high total acidity of a wine, whilst 

 the latter maintains that it tends to magni fy the impression gained 

 alxHU the volatile acidity of the wine on tasting. Worttiiann 

 points out how easily a fairly low volatile acidity is noticeable on 

 tasting a thin and light wine. i ie therefore recommends that. 

 in douhtful cases, the wine be somewhat diltited with water so 

 as to be able to detect the volatile acids more easily. 



We shall now briefly consider what limits of volatile acidity 

 in -ii'iiies have been proposed by different people to classify wines 

 as sound or unsound according to this criterion. Mathieti (11) 

 states that, in wines with a normal taste, the volatile acidity varies 

 from 0.21 to 1 .22 per mille, according to districts, years and age. 

 Possetto (3) quotes 2 to 2.5 per cent, as general limits for the 

 volatile acidity of wine. l^ottger (lOj states the following: 

 "The free 'Vereinigung bayrischer Vertreter der angew^andten 

 Chemie ' in 1897 adopted the following standards for the volatile 

 acidity of wines, on the pro]x>sal of W. Moslinger: 



((/) As normal are to be considered a volatile acidity of 0.9 

 per mille for (jerman white wines and 1.2 per mille for 

 German red wines. 



ih) As no more normal, but not yet to be condemned, are 

 German white wines with a volatile acidity between o.O 

 per mille. and i .2 per mille., and German red wines with 

 a volatile acidity betweeti i .2 and i .6 per mille. 



