38 THE PRODUCTION OF MAPLE SIRUP AND SUGAR. 



Pure water will hold in solution 66 per cent of pure sucrose at 

 ordinary temperatures. If there is a concentration by evaporating 

 off the water to a point where there is 66 per cent of sucrose in the 

 resulting solution, the solution is holding all the sucrose it can with- 

 out depositing some a*s crystals. In practice, crystallization some- 

 times occurs before this 66 per cent is obtained. The commercial 

 standard gallon of sirup, weighing as it does 11 pounds to the gallon, 

 contains at least 65 per cent solids, of which at best 95 per cent is 

 sucrose, and should not crystallize. If, however, the resulting sirup 

 weighs 12 pounds to the gallon, there is much more chance of crystal- 

 lization. 



Makers vary as to the question of the influence of hot and cold 

 canning on the possibility of crystallization. Some claim that tyy 

 canning hot crystallization is prevented, others vice versa, It seems, 

 however, that it is more a question of the density of the product than 

 of the heat of canning. These crystals may form in small patches 

 or may be large individual ones. Their presence in maple sirup is 

 often considered by some purchasers as an evidence of adulteration 

 by addition of rock candy, which is not true to fact. Once crystalliza- 

 tion is started, these crystals grow until solution equilibrium is 

 attained. 



Crystallization is induced in many cases by changes in tempera- 

 ture, the solutions becoming cold and then warm, hence it is well to 

 store maple sirup in a place of as even temperature as possible. The 

 first runs are more likely to show crystallization than the later ones. 



MANUFACTURE OF SUGAR FROM MAPLE SIRUP. 



" SUGARING-OFF." 



" Sugaring-off " applies to the further treatment of the maple 

 sirup by which it is made into a solid product. In careful manu- 

 facture of sirup, even from sour sap, a solid product may be produced 

 by concentrating to a higher degree. But if during manufacture 

 cleanliness has not been regarded or sour sap has been used, a solid 

 product will not result from any amount of boiling, due to the large 

 amount of inversion of the sucrose. 



The sugar, sucrose, which constitutes about 95 per cent of the 

 solids of the sap and, after evaporation to sirup with care, constitutes 

 from 90 to 96 per cent of the solids of the sirup, is easily broken 

 down or split up into two sugars known as dextrose and levulose. 

 The former of these crystallizes easily, while the latter does not. 

 It is the formation of these sugars from sucrose that tends to prevent 

 the making of sugar from certain sirups. This is also the reason 

 why late runs of sap or burned sirup or sour sirup will not yield 

 sugar and also why some sirups will produce a hard sugar while 

 others produce only a soft mushy sugar provided the finish ing-off 

 points are right. 



Where maple-sugar making is conducted as a side line to the 

 sirup making, the ordinary iron pot of the kitchen is filled nearly 

 half full with the sirup and this concentrated over the kitchen 



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