and the Method of making Wines. 217 



3d, Wine perfectly free from all extractive matter, either 

 10 confequence of its being depofited naturally by time or 

 by clarification, is not fufceptible of turning four. I have 

 expofed old wine in uncorked bottles to the ardour of the fun 

 of July and Auguft for more than forty days without the 

 wine lofing its quality ; only the colouring principle was con- 

 flantly precipitated under the form of a membrane, which 

 covered the bottom of the bottle. The fame wine in which 

 I infufcd vine-leaves, became four in a few days. It is known 

 that old wines, well purified, do not turn four. 



4th, Wine does not acidify, or become four, but when in 

 contact with the air: atmofpheric air mixed with wine is a 

 real leaven of acidity. When wine grows flat (fe poufle) it 

 fufTers to efcape, or exhales, the gas it contains, and the ex- 

 ternal air then enters to aflume its place. Rozier propofes 

 to adapt a bladder to a pipe inferted in the vcfl'cl, in order to 

 afcertain the abforption of the air and the difengagcment of 

 the gas. When the bladder fills, the wine tends to flatten; 

 if it empties itfelf, it is a fign of its turning four. 



When wine flattens, the cafk fufFers the wine to ooze 

 through the fides, and if a hole be made with a gimblet, the 

 wine efcapes with a hiding noife and foam : on the other 

 hand, when wine turns four, the fides of the cafk, the bung, 

 and the luting, are drv, and the air ruflies in with violence 

 as foon as it is un (topped. 



From this circumltance it may be concluded that wine 

 (hut up in very clofe veflels is not fufceptible of becoming 

 four. 



5th, There are certain times of the year when the wine 

 turns more readily four. Thefe periods are, the moment 

 when the fap rifes fh the vine, when it flowers, or when the 

 grapes aflume a reddifh tint. It is during thefe periods, in 

 particular, that precautions mud be taken to prevent its be- 

 coming acid. 



6th, Change in the temperature alfo promotes acidity, 

 efpecially when the heat rifes tq 80 or 90 degrees. The de- 

 generation is then rapid, and almovt unavoidable. 



The acidity of wine may be eafily prevented by removing 

 all thofe caufes before mentioned which tend to produce this 

 alteration ; and when it has begun, it mav be remedied by 

 the means, more or lei's effectual, which we are going to 

 mention. 



Baked muft, honey, or liquorice, are diflblved in wine in 

 which acidity has manifested itfelf: by thefe means its four 

 talte is corrected, being concealed by the fweetifh favour of 

 thefe ingredients. 



The 



