MAPLE SIRUP PRODUCERS MANUAL 



89 



(6) Hold the can so the top is at eye level and 

 read the value on the hydrometer scale at 

 the surface of the sirup. The value is the 

 observed or apparent density of the sirup. 



(7) To determine the true density of the sirup 



from the observed hydrometer reading, 

 measure the precise temperature of the sir- 

 up and add to, or subtract from, the ob- 

 served hydrometer reading, depending on 

 how much warmer or cooler than 68" F. the 

 sirup is, using table 14. 



GRADING SIRUP BY COLOR 



Color Standards 



Sirup should be graded before it is packaged. 

 Vermont producers are required to state on the 

 label the grade of sirup they are offering for 

 sale to consumers (131). Color is the principal 

 grade-determining factor of table sirup that 

 meets other requirements, such as density, fla- 

 vor, and cloudiness. 



The U.S. Department of Agriculture color 

 standards are designated "Light Amber," "Me- 

 dium Amber," and "Dark Amber." These corre- 

 spond to Bryan Color Nos. 6, 8, and 10. 



The original U.S. color standards were solu- 

 tions of caramel in glycerin made according to 

 Balch's U) revised spectrophotometric specifica- 

 tions for Bryan color Nos. 6, 8, and 10. Master 

 sets of these three solutions were supplied each 

 year for Federal and State inspection of maple 

 sirup. Unfortunately, these caramel solutions 

 tend to fade. They should not be kept for use as 

 standards for more than 1 year. 



U.S. Color Comparator 



The U.S. Department of Agriculture has de- 

 veloped a simple type of color comparator with 

 permanent standards of colored glass (9, 10). 

 These standards became the official U.S. De- 

 partment of Agriculture color standards for 

 maple sirup in 1950 and were adopted by the 

 Association of Official Agricultural Chemists 

 (153). The colors of the different gi-ades of sirup 

 are given in table 16. A thick layer of the sirup 

 to be tested is placed in the comparator (fig. 

 100). This aids in precise grading because the 

 standards are widely spaced on a color scale 

 when viewed in this thickness. The square con- 

 tainer provides a field of view of uniform thick- 

 ness and color, a feature that was not possible 

 with the cylindrical bottles formerly used. 



The three clear blanks supplied with the 

 color-grading kit are placed in the compart- 



PN-n96 



Figure 100. — Color-grading kit. The kit consists of the 

 official USDA permanent glass color standard mounted 

 in a comparator. The three clear blanks are in position 

 in the compai-ator. For viewing, the sirup sample in the 

 bottle to the right of the comparator is mounted in one 

 of the two openings in the comparator. 



Table 16. — Grade designations of maple sirup, 

 as determined by color 



Grade designation 



Color 



Color index 

 range ' 



U.S. Grade AA 



(New York 



Fancy or 



Vermont Fancy). 

 U.S. Grade A (New 



York No. 1 or 



Vermont A). 



U.S. Grade B (New 

 York No. 2 or 

 Vermont B). 



Unclassified (New 

 York No. 3 or 

 Vermont C). 



As light as or lighter 

 than Light Amber. 



Darker than Light 

 Amber but as light 

 as or lighter than 

 Medium Amber. 



Darker than Medium 

 Amber but as light 

 as or lighter than 

 Dark Amber. 



Darker than Dark 

 Amber. 



■ For description of color index, see p. 45. 



ments in back of the three standard glasses: 

 Light; Medium; and Dark Amber. 



The sirup to be graded is poured into one of 

 the clean square glass bottles and placed in one 

 of the two open compartments. The comparator 

 is held at a convenient distance from the eye 



