674 FOODS AND FOOD ADULTERANTS. 



sugar beet. No discrimination in such cases can be made by analysis. 

 If tbe ethereal substance which gives to maple sugar its peculiar flavor 

 could be detected and quantitatively determined, then adulteration 

 with a sugar containing none of this substance might be detected. 

 Extract of hickory- bark is said to contain the same flavor as maple 

 sap, and, therefore, even in case of being able to measure the quantity 

 of this substance, it might be added as an adulterant. 



In regard to the price of the sugars, molasses, etc., it sbould be re- 

 membered that they were purchased early in the year 1891, before 

 sugar was admitted to our ports free of duty. 



THE COLORING OP SUGARS. 



White and yellow sugars usually receive a special treatment, either 

 in the vacuum pan or the centrifugal, in order to prevent a gray or 

 " dead " appearance. In tbe case of white sugars blue ultramarine is 

 tbe substance usually employed' for tbis purpose. The coloring matter 

 is suspended in water and is applied as final wash in the centrifugal 

 immediately before stopping the macbine. This process is termed 

 "bluing." A very small amount of the color adheres to the crystals, 

 giving the sugar a whiter and brighter appearance. Some sugar 

 makers suspend a small amount of ultramarine in water and draw it 

 into the vacuum pan a few minutes before the strike is finished. In 

 addition to this treatment in the pan the sugar is also blued in the cen- 

 trifugal. It is not unusual to find sugars which have been excessively 

 blued, and which, on solution, yield a blue sirup. Fortunately ultra- 

 marine is not poisonous and no injury to health can result from its use. 



The yellow clarified sugars of the plantations are always treated 

 with a wash containing chloride of tin, commercially known as tin 

 crystal. The yellow sugars not treated with tin, soon after leaving the 

 centrifugal, lose their bright color and become a dead or grayish yellow. 

 Such sugars are only manufactured for tbe refiner, and do not enter 

 directly into the consumption. The tin crystal is dissolved in water 

 and, as in tbe case of ultramarine, is employed as a final wash shortly 

 before stopping the centrifugal. The depth of the yellow color of tbe 

 sugar depends largely upon the strength of the tin solution and is 

 modified by the manufacturers to suit the demands of the market. 



The principal constituent of the various sugar colors known as " rock 

 compound," " Smith's sugar color," etc., is chloride of tin. Tbe tin 

 chloride is not in itself a coloring matter. Tin can rarely be detected 

 in sugars known to have been colored by means of tin chloride. The 

 yellow color produced by this substance is probably a result of its ac- 

 tion on the sugar itself. 



Tin crystal is also employed in the vacuum pan, but not generally in 

 this country. In the manufacture of the beautiful sugar known as 

 " Demerara crystals," chloride of tin is employed in the vacuum pan. 

 Sulphuric acid was formerly used for this purpose, but it has been su- 

 perseded by the tin compound. 



