APPENDIX B. 



JOHANN CARL LEUCHS ON WINE-MAKING. 



I. Fermentation. The After Fermentation. — 11. Implements used in Wine-making: 

 The Thermometer. Table of Scales of different Thermometers. The Areometer. 

 The Acid Scale. — III. MunvfacturiiHj Grape Wines: General Observations GatL- 

 cring the Grapes. Crushing and rressing. Fermentation. Filling in the Musi. 

 Making Sweet Wine. Making Frozen Wine. Making new Wines appear old. — 

 IV. Classification of Wines. — V. Drawing off the Wine. — VI. Treatment of bot- 

 tled Wines. Filling up and Wasting. — VII. Clarifying Wines. — VIII. Giving 

 Color to Wines. — IX. Mi.xing and judging of Wines. — X. The principal Diseases 

 o/" TFtnes; Sudden Changes. Souring. Becoming Glutinous. Woody, mouldy, 

 and bitter Taste. Cloudiness and Muddiness. — XI. Adulterations of Wines. — 

 XII. Uses for the Husks and Sediment. — XIII. The Cellars, Casks, Bottles, and 

 Implements. — XIV. Wine Measures of all Countries. 



FERMENTATION. 



In the process of fermentation, carbonic acid is produced by a 

 cbemical process which is explained in all l^ooks upon chemistry. 

 In the formation of carbonic acid caloric is liberated, and the fer- 

 menting liquid becomes heated. The more active the fermenta- 

 tion, the greater is the amount of heat produced. When large 

 quantities of grape-juice are fermented together, care must be taken 

 that it is carried on at a reduced temperature, otherwise the heat 

 would become too great. The general rule is, that if a vessel 

 containing five hectolitres requires from 25° to 28°, one contain- 

 ing ten hectolitres requires from 15° to 20°, and one containing 

 thirty or more hectolitres requires from 12° to 15°.* The heat 

 of fermentation appears to be mainly produced by the formation 

 of the carbonic acid, as it is in ordinary combustion, in which this 

 gas is likewise developed and heat produced. In fermentation, 

 however, the increase of temperature is not so perceptible as in 

 combustion, for the process goes on but slowly, and the heat de- 

 veloped is dispersed by radiation and conduction ; and, moreover, 

 a considerable part of the heat becomes latent by the evaporation 

 of the water contained in the juice. When large quantities of 

 juice are fermented together, the increase of temperature, howev- 

 er, becomes quite perceptible. It decreases as the fermentation 

 lessens, and also when the larger part of the sugar is decomposed. 

 It has been calculated that, in the fermentation of a mash of malt 



* The degrees of temperature given here, as elsewhere in this treatise, are those 

 of Reaumur, whose thermometer is generally used in Germany. These may be con, 

 verted into their equivalents of Fahrenheit and Celsius by the table on page 196. 



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