390 GRAPE CULTURE AND WINE-MAKING. 



mains after this process is tlie impurities, wliich will serve to form 

 an estimate of the goodness of the starch-flour. 



Steam is used to boil the sugar ; and to complete the fabrication 

 of from 1000 to 1500 pounds of sugar, it will require an engine of 

 four atmospheres proof. The vessel in which the starch is boiled 

 may be of good oak staves, 1^ inches thick, or of pine staves, lined 

 on the inside with lead. For the fabrication of 1500 pounds of 

 grape-sugar daily, the size of this vessel may be : the height, four 

 feet nine inches ; upper width, four feet three ; and the diameter 

 of the bottom, the same. The steam-pipe enters the bottom of 

 this vat, and is coiled there in a few turns. The upper side of 

 the coil is supplied with many small holes for the escape of steam ; 

 the end of the pipe is closed. 



The starch, destined for grape-sugar is mixed witli water to a 

 thickness of molasses, in a vat used for the purpose. At the same 

 time, 18 gallons of water are poured into the boiler. For every 

 1000 pounds of starch-flour, 2-1 pounds of English vitriol are added. 



The steam is let on, and when boiling, portions of thinned 

 starch, consisting of two gallons, are added slowly. Care must 

 be taken that this fluid does not cease boiling, and also that the 

 addition of the starcb is done very regularly, to prevent it from 

 forming paste ; and also the fluid must not boil too much, for oth- 

 erwise it may run over. During the boiling of the substance 4t 

 may be often skimmed. 



Starch-flour boiled with vitriol will first form dextrine, and after- 

 ward grape-sugar. The complete transformation into sugar will 

 require about ten hours. 



2. Neutralization of the Acid and Clarifying of the Sugar. — For 

 the neutralization of the acid will be taken carboniferous lime- 

 stone, in form of ground limestone. One third of the substance 

 required will be put in the neutralization vat ; at the same time, 

 put into the vat 24 pounds of ground bone-black. Now the sugar 

 solution may run slowly into this vat, and be kept well stirred, 

 to help the generation of carbonic acid and the forming of gyp- 

 sum. If the lime is exhausted, more must be added, until the 

 last of the sugar is drawn off. To know when the process is fin- 

 ished, the following experiment may be tried: After the solu- 

 tion has been stirred a quarter of an hour, take out a small por- 

 tion and filter it. Take strips of blue litmus paper, and moisten 

 them with the filtered fluid. If the paper, after being completely 

 dry, turns reddish, then the acid is not fully absorbed, and lime 

 in smaller quantities may be added, until this process will show 

 the litmus paper in its original blue color. 



After the neutralization of acid, it is necessary to free the solu- 

 tion of sugar immediately from the gypsum, otherwise the sugar 

 would become of a bitter taste, and its color would be dark. 



3. Filtration through Bone-black. — For this work arc required a 

 good press and a wooden frame containing about ten small linen 



