Micro-organisms of Maple Sap 423 



The average water content for the group is 34.06%. This 

 figure is about normal, yet individual sirups vary from 39.78 to 

 29.96%. The sucrose shows the usual variations depending on 

 the moisture content, ranging from 58.46 to 67.89, and averaging 

 63-5 1 %• When calculated to a dry matter basis these large 

 variations are eliminated and the average sucrose content becomes 

 96.32%. The invert sugar varies from 0.13 to 1.05. averaging 

 0.39%. Investigation has shown that there are but very small 

 amounts of invert sugar in the sap of the maple as it comes from 

 the tree, and, consequently, if quickly and properly concentrated, 

 flie resulting sirup should carry only a small amount. When 

 the invert sugar in maple sirup calculated to a moisture free 

 basis is less than 0.60%, it should not be attributed to excessive 

 micro-organic infection. No. 20 was obtained about the 

 middle of the season of 1909 from sap held 3 days in the cold ; 

 and its invert sugar percentage, 1.05, would indicate that the 

 sucrose had suffered a slight decomposition. 



The minimum ash and malic acid value figures estab- 

 lished by the writer for pure Vermont maple sirup of standard 

 weight and density, together with similar data obtained by 

 Bryan for Vermont as well as for the United States-, arc shown 

 in the following table : 



TABLE 17. MINIMUM ASH AND MALIC ACID VALUES FOB PURE MAPLE SIRUP 



Calculated to a moisture-free basis 



The agreement on the Vermont samples is very close. The 

 Jones standard was secured on samples made in 1904 and the 

 Bryan results on those obtained in 1909. Tn both cases they 

 are based on about 50 samples representing all grades of pure 



l Vt. Sta. Rpt. IS, p. 334 (1905). 



a U. S. Dept. Agr., Bu. Chem., Bui. 134, pp. 74-75 (1010). 



