Why honey crystallizes?

Honey is a highly concentrated sugar solution. It contains more than 70%

sugars and less than 20% water. There is much sugar in honey relative to

the water content. This means that the water in honey contains an extra

amount of sugar than it could naturally hold. The overabundance of sugar

makes honey unstable. 

It is natural for honey to crystallize since it is an over-saturated sugar

solution. The two principal sugars in honey are fructose (fruit sugar) and

glucose (grape sugar). The content of fructose and glucose in honey

varies from one type of honey to the other. Generally, the fructose ranges

from 30- 44 % and glucose from 25- 40 %. The balance of these two

major sugars is the main reason that leads to crystallization of honey, and

the relative percentage of each determines whether it crystallizes rapidly

or slowly. What crystallizes is the glucose, due to its lower solubility.

Fructose is more soluble in water than glucose and will remain fluid.

When glucose crystallizes, it separates from water and takes the form of

tiny crystals. As the crystallization progresses and more glucose

crystallizes, those crystals spread throughout the honey. The solution

changes to a stable saturated form, and ultimately the honey becomes

thick or crystallized.

Some honeys crystallize uniformly; some will be partially crystallized and

form two layers, with the crystallized layer on the bottom of the jar and a

liquid on top. Honeys also vary in the size of the crystals formed. Some

form fine crystals and others large, gritty ones. The more rapid honey

crystallizes, the finer the texture will be. Crystallized honey tends to set a

lighter/paler colour than when liquid. This is due to the fact that glucose

sugar tends to separate out in dehydrating crystals form, and that glucose

crystals are naturally pure white. Darker honeys retain a brownish

appear.