If you hope to create a smooth, creamy, or chewy candy, there is a particular kind of sugar you must add to your mix: glucose. In candy making, glucose creates long carbohydrate molecules that get all tangled up and prevents the other sugars from crystallizing. This is the molecular action that makes hard candies glassy rather than crystalline, and keeps grittiness out of butterscotch, caramels, and taffies.
In the early 1900s Americans were becoming more aware of the techniques of food manufacture in the new food industries. One worry was “adulteration”: were the factories adding cheap or harmful substances to the food they sold?
Commercial candy makers were under special scrutiny. They made chemically complicated concoctions, with strange and unfamiliar colors and flavors and qualities, and they sold them to children. Were the dyes and flavorings and ingredients really safe?
Some weren’t, to be sure. But one that got everybody riled up was “glue.” Glue obviously didn’t belong in candy; yet there it was, right on the list of ingredients: “gluecose.”
Dr. Cutler, a representative of the American Manufacturing Association of Products from Corn, explained the problem in a 1914 address to the National Confectioners Association:
The word ’Glucose’ is derived from that of ’Glukos, ’which was the name given to starch which had been converted into syrup, for the reason that it was sweet. The English spelling of the word was ’Glucose,’ which very easily became misspelled ’Gluecose,’ hence the conclusion by uninformed people that it was a product of ’glue,’ and as glue is made from a variety of objects such as animal hoofs, old bones, fish, etc., ’Glucose’ naturally enough became blacklisted by many. … It was found that even physicians and school teachers were actually teaching and preaching about the dangers and impurities of ’Glucose’.
Confusion about the relation between “glue” and “glucose” became so acute that the corn industry, the primary supplier of glucose, had to act. They went to congress to pass a law allowing glucose to be known henceforth by a name that would forever clear up the “glue” confusion, and would instead imply all that was wholesome and pure. So you won’t find glucose on the list of ingredients any longer. Look for this water-binding simple sugar under its common name: “corn syrup.”
For the story of corn syrup’s rise as a sugar substitute, see my post Corn Into Candy: 1918
Source: “Corn Syrup Education,” International Confectioner June 1914; Harold McGee, On Food and Cooking: The Science and Lore of the Kitchen (1984).
More on the science of Corn Syrup in candy making at Laura’s Candy Science Tuesday on Candy Dish Blog