Crystallization of honey is a natural process that does not indicate spoilage. Nearly all kinds of liquid honey will crystallize in time. The rate of crystallization is related to honey composition, storage conditions, and the amount of heating and filtering. Some honeys granulate uniformly throughout, while others will leave a liquid portion at the top. The faster honey granulates, the smaller the crystals will be. Slow granulation produces large, coarse crystals.

Honey is a supersaturated solution (containing more dissolved material than can normally remain in solution) composed primarily of two sugars, dextrose (glucose) and levulose (fructose), dissolved in about 17 percent water. Such solutions are more or less unstable and in time will return to the stable saturated condition with the excess material coming out of solution. During granulation, dextrose separates from the liquid phase as crystals, while the other sugars remain in solution. As crystallization proceeds, the moisture content of the liquid phase increases, producing a favorable medium for fermentation. Honeys high in dextrose crystallize rapidly; those high in levulose granulate very slowly. The ratio of dextrose to levulose reflects that of the floral sources worked by the bees.

Crystallization is delayed by heating and filtering. Heating dissolves sugar crystals that may be present in the honey, and filtering removes tiny particles (pollen grains, wax, impurities, etc.) on which crystals form. Low-moisture honeys granulate more slowly than high-moisture honeys.

The most favorable temperature for granulation is 57° F (14° C). Storage of honey at room temperature will delay granulation. Small quantities may be frozen for several years before crystallization takes place.

Reliquefying Granulated Honey
Honey with coarse, gritty crystals is undesirable to the consumer. To reliquefy, containers of crystallized honey can be placed in a hot, dry chamber or in a hot-water bath until all crystals are completely liquefied. If a dry chamber is used, there will be no damage to the labels on the containers. Do not heat the honey higher than 145° F (63° C) since it scorches easily. Buckwheat honey may burn at 140° F (60° C). Honey must be cooled as soon as it becomes clear to prevent discoloration and loss of flavor. When heated in 60-pound cans with the cans kept right side up, the honey must be stirred every hour; otherwise, the honey next to the outside of the can will be overheated before the center is liquid. If the container is placed in hot water, the water should come near the top of the container.