WINE AND THE ART OF WINE TASTING. 33 



the wine loses its limpidity, becomes cloudy, and a black precipitate is 

 formed; meanwhile the taste of the wine often changes. The black 

 substance may be decolorized by sulphurous acid; the use of this sub- 

 stance arrests or retards the blackenfhg of the wine. 



Wines made from grapes poor in tartaric, malic acid, etc., like those 

 which have been gathered when wet with dew or rain, or those which 

 have been injured by cryptogams, are liable, when exposed to the air, to 

 become cloudy and dark in color. 



The presence of an excess of iron in the white wines of certain locali- 

 ties of the southern provinces is the reason why, when they are at all 

 exposed to the air, their color changes to a blackish green. 



Not southern wines alone, but also those from northern provinces, 

 when they do not contain a sufficient quantity of acid, and more espe- 

 cially of tartaric acid, acquire this color. Chemists explain this phe- 

 nomenon in different ways, though all admit that it is due to the presence 

 of some of the compounds of iron. Nessler tells us that wines produced 

 on soils rich in the salts of iron, and even wines which have been for 

 any length of time in contact with iron, as happens when there is an 

 iron rod between the heads of the cask, or when there are nails in the 

 cask, etc., if they become exposed to the air, turn black, for then the 

 protoxide or ferrous oxide contained in the wine changes in contact with 

 the air to sesquioxide or ferric oxide. A black compound is then formed 

 by the combination of the ferric oxide with the tannin; this black color 

 is not obtained with the protoxide. Other chemists explain the phenom- 

 enon by supposing that there occur or are formed in the wine certain 

 humic products analogous to those which are formed by the decomposi- 

 tion of vegetable substances. These substances are feebly acid, and have 

 a considerable dissolving power on the iron. Thus there are formed in 

 the wine certain of the lower compounds of iron, which, on exposure to 

 the air, change to the higher compounds, and give the wine the black- 

 ish tint before spoken of. The wine then becomes turbid, and the flavor 

 undergoes certain peculiar changes. 



Formerly some sparkling wines were made of this color, but now it is 

 no longer found but as a defect. 



DIRTY (Sporco, It.; Terne, Fr.). A diseased, badly made, or badly 

 kept wine sometimes becomes turbid, and its natural color is masked 

 by other colors, giving the impression of something soiled or dirty. 



Among red wines the following are the colors most generally recognized; 

 they may be of more or less intensity: 



VERY LIGHT RED (Claretto, Chiarello, Chiaretto, It.; Clairet, Fr.). 

 These terms are used to describe a class of wines which contain the 

 least color of any red wines; the cause of this poverty of color may be 

 in the nature of the grape, the mode of preparation, or it may be that 

 the wine has been diluted with water. 



These wines form the connecting link between white and red wines. 



Trinci, writing of these wines, says: "The French 'claretto' is a 

 smooth, vinous, lightly colored wine, with little aroma; slow and long 

 in maturing, and not pleasing when drunk alone; blended, however, in 

 proper proportion, it is extremely good." 



The "claretto" drunk by Redi, however, must have been very differ- 

 ent from this, or he would not have written : 



" Benedetto 

 Ouel claretto 

 Che si spilla in Avignone." 



