Glucose, also called dextrose, is a simple sugar, and the most common sugar from which living cells directly extract chemical energy. Glucose is found in many fruits and in honey, but always in a mixture with other sugars. It’s the building block from which starch chains are constructed. Cooks encounter it most often as the sweet substance in corn syrup, which is made by breaking starch down into individual glucose molecules and small glucose chains. A chain of two glucoses is called maltose. Compared to table sugar, or sucrose, glucose is less sweet, less soluble in water, and produces a thinner solution. It melts and begins to caramelize at around 300°F/150°C.