SIMPLE PURITY' AND ADULTERATION TESTS 243 



during the drying operation in its preparation for the market. Compare with 

 a sample of coffee. 



Coffee substitutes generally contain starch which may be easily 

 detected by its giving a characteristic blue with iodine. 



Moisten one tablespoonful of the coffee with cold water, add one cup of warm 

 water, bring to the boiling point, and boil for two minutes. Filter through 

 a funnel lined with cotton. The coloring may be removed by passing the 

 liquid through charcoal. When cold, add a few drops of weak iodine; a blue 

 color will appear if cereals, peas, beans or other starch-containing substances 

 are present. 



Vinegar. Vinegar has been very largely subject to substitution 

 and imitation. The best varieties on our market are cider, wine, 

 and malt vinegar. 



Substitution may be detected by slowly evaporating almost to dryness 

 one-half cup of vinegar in a small saucepan and examining the warm residue. 

 If there is a distinct odor of baked apples, it is cider vinegar; of grapes, it is wine; 

 of malt, it is malt vinegar. Distilled vinegar gives a burnt sugar odor. No 

 residue indicates synthetic vinegar. 



All these products are harmless. Synthetic vinegar is the near- 

 est approach to pure a.cetic acid, but, as it contains less dissolved ma- 

 terial, it lacks flavor. As a rule, cider or wine vinegar is preferred 

 in this country, though in England malt vinegar is largely used. 



Extracts of Lemon and Vanilla. Oil of lemon is soluble only 

 in strong alcohol. 



Dilute a portion of the suspected extract with water. If it becomes cloudy, 

 it is oil of lemon, being thrown out of solution by the weakened alcohol. 



If the sample remains clear after the addition of water, a sub- 

 stitute has been used. Oil of lemon is much preferred to any sub- 

 stitute. 



Vanilla extract: The substitution of a synthetic product, arti- 

 ficial vanillin, is frequently practiced. 



As it is usually colored with caramel, it may be easily detected by thor- 

 oughly shaking the mixture and observing the foam. If caramel is present, the 

 color remains at the point of contact of the bubbles with the liquid until the 

 bubbles disappear. The foam of the pure extract is colorless. 



