Crystallization
Lexikon
Honey crystallizes as soon as a sugar exceeds its saturation limit and precipitates out of the supersaturated solution.
Honey crystallizes as soon as a sugar exceeds its saturation limit and precipitates out of the supersaturated solution. The decisive factor is glucose, which is already saturated at around 32 grams per 100 grams of honey. Fructose practically never crystallizes out in honey.
How quickly a honey sets therefore depends above all on the ratio of the two sugars. Rapeseed honey has a very high glucose content and sets within days, while robinia, sweet chestnut and fir honey stay liquid for a long time. Honeydew honey additionally contains melezitose, a trisaccharide that crystallizes strongly and, in extreme cases, produces the well-known cement honey.
Water content and temperature also play a role. The tendency to crystallize is strongest at a water content between 14 and 18 percent. The Celle Bee Institute distinguishes two temperature ranges: crystal nuclei form preferentially at around 4 to 5 degrees, and crystals grow fastest at 14 to 16 degrees. From about 25 degrees crystallization decreases, and above 30 degrees the crystals melt again.
For liquefying there is a hard limit: the honey itself must never exceed 40 degrees, otherwise enzymes and aroma suffer and the HMF content rises. A warming cabinet at around 35 degrees has proven effective. Customers often think crystallized honey has gone bad or been adulterated. The opposite is true, because only heavily heated or filtered honey stays liquid permanently.