96 



AGRICULTURE HANDBOOK 134, U.S. DEPT. OF AGRICULTURE 



F'N-IK(I1 



Figure 105. — A separate room built in the evaporator 

 house makes an ideal candv kitchen. 



PN-4802 



Figure 106. — Gas, whether supplied from tanks or mains, 

 is a good source of heat for cooking maple products. The 

 heat is.easily controlled and can be stopped the instant 

 cooking is completed. Here, sirup is being cooked for 

 maple cream. 



hold scale. Provision should be made for cooling 

 the sugar products. This is especially desirable 

 when making maple cream, fondant, or crystal- 

 coating sirup. The cooler for cream can be a 

 trough with circulating cold water into which 

 the pans of cooked sirup are placed. A pan of 

 chipped ice or ice water may also be used. For 

 crystal-coating sirup, an insulated box, such as 

 a used refrigerator from which the cooling unit 

 has been removed, may be used. 



Mapir .Siifiar 

 ('ln'ini.ttry of Mii/ilf Siifiar 



Maple sirup is essentially a solution of su- 

 crose in water. The amount of sugar that can 

 be in true solution in a given volume of water 

 varies with the temperature of the solution ill, 

 12, 51, 82). Hot solutions can contain more sugar 

 and cool solutions less sugar. 



Maple sirup solutions containing 67 percent 

 of sugar (67° Brix) are saturated at room tem- 

 perature (68° F.). That is, no more sugar can be 

 dissolved in the solution at that temperature. 

 Sirup that has been heated to raise the boiling 

 point of the sirup to 7.5° F. or more above the 

 boiling point of water will be supersaturated 

 when it cools to room temjierature; it will con- 

 tain more than 67 percent of sugar. This super- 

 saturated sirup, with its excessive sugar con- 

 tent, is in an unnatural or abnormal condition, 

 and it tends to return to normal by ridding 

 itself of the excess sugar so that the sirup will 

 again contain only 67 percent of sugar. The 

 excess sugar is forced out of solution (precipi- 

 tated), and sugar crystals are formed. The 

 slower this occurs, the larger the sugar crys- 

 tals. 



To make any of the maple sugar products, it 

 is necessary first to make supersaturated sirup. 

 The degree of supersaturation is increased as 

 the boiling temperature of the sirup is in- 

 creased and more water is evaporated from the 

 sirup. When the amount of supersaturation is 

 small and cooling is slow and is accompanied by 

 little or no agitation, the state of supersatura- 

 tion may persist for a longtime; and little sugar 

 will be precipitated. When the amount of super- 

 saturation is appreciable, as when sirup is 

 boiled 'to 18° F. or more above the boiling }X)int 

 of water (11° or more above that of standard- 



