Why does Honey Crystalize? The truth is that the crystallization of honey is a natural and uncontrolled process. Containing more than 70% sugars and less than 20% (18% or lower is optimal) water, honey is naturally an unstable super-saturated sugar solution. Hence, over time, almost all pure raw honey crystallizes.
The composition ratio of glucose and fructose in a floral nectar source is one way to determine how fast the honey crystallizes. Honey varieties with a low fructose to glucose ratio, such as Dandelion, Aster, Clover, and Goldenrod honey crystallize swiftly in days and weeks, while honey varietals with a high fructose to glucose ratios such as, Tupelo, Acacia, Longan, Eucalyptus, Sourwood, crystallize slowly and stay liquid for years. During crystallization, glucose separates from water and become crystals, while fructose remains as a liquid. The honey thickens and becomes more viscous. The size of the crystals formed varies from honey to honey; some varietals form fine crystals while others large ones. (This is the reason why some honey varietals crystallize to form a coarse sugary texture, and some varietals crystallize to form a smooth creamy consistency.) Even though the formation of crystals has absolutely no bearing on the quality of honey, most people still reject honey that is sugary and coarse in texture.
Besides, floral sources, pollen content or other particles will make honey crystalize faster. Think back to elementary school and the experiment of mixing sugar water in a jar, then inserting a string. The string gave something for the sugar to attach to and voila' ROCK CANDY is born. So even, though pollen is good for the health benefits of honey, it will give the sugars something to attach to and hence crystalize quicker.
Moisture content is another factor in crystallization. The higher over 18% moisture, the faster the crystals will form. Take that moisture into the 20's % and fermentation may even take place.
Yet another factor is temperature, cooler temps will hasten the crystallization process. Honey stored in a refrigerator or cooler basement or cold garage in winter will turn your liquid gold into a sweet treat that is hard as a rock. However; honey may be frozen, seems like the flash freezing of honey in frames doesn't quite have the same effect as prolonged cool temperatures, it may be thawed and extracted and bottled without effecting the time to crystallization.