Corn syrup is just what the name implies, a liquid derivative of corn starch, that is primarily the sugar called glucose. It is used extensively in the manufacture of processed foods and beverages in the US, because it does not crystallize as readily as sugar and is generally less expensive (although it is also not as sweet as sugar).

It is available to consumers in the US in two forms – light, which has been clarified to remove all color (and which is essentially flavorless), and dark, to which caramel color and molasses have been added. Because of its tendency not to crystallize, it is often called for in recipes for frostings, candies, jam, and jellies.

If light corn syrup is not available, you can substitute a sugar syrup made with 1-1/4 cups sugar and 1/3 cup water, boiled together until syrupy. If your recipe calls for dark corn syrup, we’d suggest using a sugar syrup with a dash of dark treacle or unsulfured molasses, both of which are derived from sugar cane.