This section is from the book "A Treatise On Beverages or The Complete Practical Bottler", by Charles Herman Sulz. Also available from Amazon: A Treatise On Beverages.
The coarse adulteration with starchy substances is easily recognized in the soluble matter left on treating with alcohol, and by the blue color produced on the addition of solution of iodine. Adulterations with artificial grape-sugar prepared from starch by boiling with sulphuric acid are difficult to establish; aside from the physical properties, the presence of soluble sulphate (of calcium) affords the best criterion. Beet-root molasses contains chlorides, and if used for adulterating honey causes a white precipitate with silver nitrate. Starch-paste added with the view of rendering honey thick is deposited as a jelly-like, stringy mass on dilution with water. Neither crude honey or honey clarified by the process of the United States Pharmacopoeia yields with water an absolutely clear solution. The test given by the Pharmacopoeias are as follows: "If one part of honey be dissolved in four parts of water, a clear solution should result, which should not be rendered more than faintly opalescent by a few drops of test solution of nitrate of silver1 (chloride) or of nitrate of barium (sulphate). If a small portion of honey be diluted with one volume of water, and then gradually mixed with five volumes of absolute alcohol, it should not become more than faintly opalescent, and should neither become opaque nor deposit a slimy substance at the bottom and along the sides of the test-tube (starch, dextrine). When incinerated in small portions at a time in a platinum crucible, it should not leave more than two per cent of ash (any larger percentage of ash and failure to respond to the preceding tests indicating the presence of glucose or other foreign admixtures). Water boiled with honey and allowed to cool should not be rendered blue or green on the addition of test solution of iodine1 (absence of starch)". - U. S. "It mixed with an equal bulk of ammonia-water, the color of honey should not be altered (absence of turmeric, aniline colors, etc.)". - P. G.
1Nitrate of silver dissolved in 20 parts of water.
1Iodine 1 part and potassium iodide 3 parts, dissolved in water 50 parts.