MAPLE SIRUP PRODUCERS MANUAL 



115 



Figure 123. 



PN-1S19 

 -Testing sirup for invert sugar. 



Write down in order the values you have 

 griven the five dilutions, starting with the 1-and- 

 12 dilution at the left. 



Special Note. — If the first sirup you test 

 proves positive in some dilutions and negative 

 in others, you will quickly see the difference 

 between a positive and a negative color reac- 

 tion. 



It is possible, however, that the sirup you test 

 will give a positive or a negative test in all 

 dilutions. If this happens and you ai'e doubtful 

 about your interpretation of the results, it will 

 be helpful to have a solution that you know will 

 give a jx)sitive test. 



To prepare such a solution, add three drops of 

 corn sirup to the 4-ounce glass containing the 

 sample of the l-and-60 dilution. Stir the com 

 sirup into the dilute sirup. 



In a clean test tube place five drops of this 

 solution. Add 10 drops of water, then one Clini- 

 test tablet. After boiling has stopped add water 

 until the test tube is two-thirds full. 



The color that develops will indicate a posi- 

 tive reaction. 



(6) Fifteen seconds after the boiling stops, add 

 water to the test tube marked "60" imtil the 

 tube is two-thirds full. Add the same amount of 

 water to the other four test tubes, in order, 

 from right to left. 



(7) Compare the colors in the test tubes with 

 the two colors of the color scale marked "trace" 

 and "-f^". Disregard everything else on the 

 scale; the other colors and the labels on all the 

 colors have no relation to this test. 



Make this comparison in a room lighted with 

 an incandescent bulb. You cannot judge the 

 colors of the solutions for this test with fluores- 

 cent light or with sunlight only. 



Assign to the mixture in each tube one of 

 three values — positive (+ ) for invert sugar, neg- 

 ative (-) for invert sugar, or doubtful (±) ac- 

 cording to the following standard: 



Color of solution Value 



Same as or more blue than color on scale 



labeled "trace" Negative (-) 



Same as or more yellow than color on 



scale labeled " + " Positive ( + ) 



Between "trace" and " + " colors on scale Doubtful (± ) 



Detorniiiiiiig In>ei't Siiftar Content of 

 Sirup 



To find the invert sugar content of the sirup 

 you are testing, find the line in table 17 that 

 contains the same combination of values for the 

 five dilutions that you obtained in the color 

 test. 



As the table shows, the sirups that are most 

 suitable for making into cream are those that 

 are negative in all dilutions or positive in the 

 first (l-and-12) dilution and negative in all the 

 others. 



Suniniaiy 



(1) Test the sirup for its invert sugar content 

 before attempting to make maple cream. 



(2) Use the simple or shortcut test, page 113. 



(3) To check the color, positive or negative, use 

 a test .solution consisting of the 1- and 60- 

 solution to which is added com sirup, page 

 115. This will give a positive test. 



(4) Sirup containing more than 3 percent of 

 invert sugar is unsuitable for creaming. 



