108 



AGRICULTURE HANDBOOK 184. U.S. DEPT. OF AGRICULTURE 



Always bring the hand to the nose; do not bend 

 over the kettle. 



At the end of the cooking period, the thick, 

 supersaturated sirup is cooled to I8(f F. Ap- 

 proximately 3 pints of water is added for each 

 gallon of sirup originally used to replace the 

 water lost in evaporation and restore the sirup 

 to standard density. Extreme caution must be 

 exercised in adding the water because the 

 water will be converted to steam with explosive 

 violence if the sirup has not cooled to a temper- 

 ature below the boiling point of water. 



After addition of the water, the sirup is again 

 brought to a boil and heating is continued until 

 the temperature reaches that of standard-den- 

 sity sirup (7 F. above the boiling point of 

 water). 



As flavor and color in sirup develop initially 

 to the same degi'ee, flavor development in the 

 treated sirup may be measured indirectly by 

 measuring the increase in its color. A sample of 

 the high-flavored, standard-density sirup is 

 weighed and then diluted with a colorless cane 

 sugar sirup having a density of 66° Brix as 

 measured with a hydrometer or refractometer. 

 The colorless sirup is added slowly to the high- 

 flavored sirup, with thorough stirring, until the 

 mbcture matches the color of the original maple 

 sirup. Then the mixture is weighed. The in- 

 crease in color and flavor is determined by the 

 ratio. 



Weight of mixed sirup 



Weight of high-flavored sirup 



= Increase in flavor 



This procedure can be used to follow the 

 progi-ess of the high-flavoring process, since 

 different lots of sirup of the same grade develop 

 flavor at slightly different rates. A sample is 

 removed periodically from the cooking sirup 

 and weighed. Enough water is added to restore 

 the sample to standard density (66' BrLx), and 

 its increase in color and flavor is determined. 

 The tests are easy to make; the 2-ounce French 

 squai-e bottle supplied with the U.S. color com- 

 parator (described on p. 89) is used. The high- 

 flavor process and its end uses are shown in 

 figure 121. 



l'rfssiir<'-( DoLiiifi I'rnifss 



Many maple producers do not have higli- 

 pressure Steam equipment. They may make 



A NEW MAPLE PRODUCT 



■IJ^ 



PN"-48n 



Figure 121.— A schematic drawing showing the high- 

 flavoring process and its use in making blended sirup 

 and as a food flavoring. 



high-flavored sirup by the pressure-cooking 

 process {139}. In this process, standard-density 

 sirup is heated in a closed vessel, such as an 

 autoclave or ordinaiy pressure cooker, at 15 

 pounds' pressure. Best results are obtained 

 when the sirup is heated to a temperature of 

 25(f to 253° F. as in the atmospheric process. 



In the pressure-cooking process, the water 

 content of the sirup is 34 percent during 

 heating rather than 10 percent, as in the at- 

 mospheric process. The higher water content 

 favors formation of caramel. However, the rate 

 at which caramel forms depends on the original 

 caramel content of the sirup. The higher the 

 caramel content in the original sirup, the 

 greater the amount formed in the product. 

 Since the amount of caramel in sirup is related 

 to the amount of color, only U.S. Grade AA 

 (Fancy) or U.S. Grade A (No. 1) sirup should be 

 used to make high-flavored sirup by the pres- 

 sure-cooking process. Darker grades usually re- 

 sult in an unpalatable product. 



The sirup is heated almost to boiling and 

 immediately is transferred to jars, which are 

 filled to vvithin '., inch of the top. The lids are 



