Honey is sometimes used as a liquid sugar substitute. However, "substitute" is not quite accurate because honey gets its sweetness from sugar; in fact, several types of sugar. What we think of as sugar is a combination of carbohydrates linked together in different structures. Honey can contain up to 24 different sugars.
In its granulated form, sucrose is simply table sugar, the sweet white crystals you sprinkle in coffee and use in recipes. Sucrose is a disaccharide, formed when fructose and glucose, which Georgia State University defines as “simple” sugars or monosaccharides, link up. An oxygen atom connects the two monosaccharides, and the Exploratorium website notes that an acidic substance like lemon juice can break that bond.
Fructose and Glucose
Honey contains additional loose molecules of fructose and glucose. Fructose is better known as the sugar found in fruit, and glucose is the same simple sugar that the body needs for energy. A 1980 article by J. W. White, Jr., and Landis W. Doner in the USDA Agriculture Handbook Number 335 says that fructose and glucose, also known as levulose and dextrose, respectively, form about 85 percent of the sugar content in honey.
Maltose is also called malt sugar. It is a disaccharide that contains two glucose molecules. Elmhurst College says maltose is the same sugar formed when grain is allowed to reach its highest starch content and then heated when making beer. It is used as a sweetener in foods in its own right, and is sometimes used to coat food such as duck skin to make it crispy.
White and Doner state that honey contains several other sugars, many of which occur from chemical and enzyme reactions or are added during processing. Honey was originally considered a mix of sucrose, fructose, glucose and what White and Doner call honey dextrin, which they say was not well-defined. Honey dextrin was later revealed to be a mix of several di- and trisaccharides, including maltose, maltotriose, theanderose, kojibiose, isopanose, centose, erlose, panose, maltulose, gentiobiose and turanose; plus two more complex sugars, isomaltotetraose and isomaltopentaose.