What is the deal with honey crystallization and bubbling
Introduction: In daily life, it is common to encounter a situation where honey purchased and stored for a period of time will crystallize. Sometimes, you may also see a layer of white foam on the surface of the honey. Many people suspect that this is due to spoilage or poor quality honey. Don't worry, the following will explain what causes honey to crystallize and foam.
What is honey crystallization?
Honey crystallization is a common issue encountered when consuming honey. As time passes and the temperature changes, honey often transitions from a liquid state to a crystalline one, with its color lightening. This change in honey often leads to some misunderstandings, with people believing it is caused by the addition of white sugar. In reality, this is a natural change in honey, not the result of added sugar.
Honey is a supersaturated solution of glucose and fructose, containing a variety of nutrients. Due to the crystalline nature of glucose, separated honey will gradually crystallize when stored for a period at a lower temperature. The speed of its crystallization is related to the number of glucose crystallization nuclei, temperature, moisture content, and the nectar source.
The speed of honey crystallization is also affected by temperature. It crystallizes most easily at 13-14°C. If the temperature is below this, the increased viscosity of the honey slows down crystallization. If the temperature is above this, the increased solubility of the sugar reduces the supersaturation of the solution, also slowing down crystallization. Crystallization is not an immediate process upon placing honey in the refrigerator; it is a long-term physical process.
Honey crystallization is also related to the type of honey and its water content. For instance, acacia honey, pagoda tree honey, and raw wild honey are less prone to crystallization, while rapeseed honey, cotton honey, and sunflower honey are more likely to crystallize, sometimes even when freshly produced. Fully crystallized honey generally has a low water content, making it suitable for long-term storage without spoilage. Unripe honey with a high water content has a lower degree of supersaturation, which can slow down or prevent complete crystallization. In this case, the crystallized glucose settles at the bottom, while the thinner honey remains on top. The nutritional content of this semi-crystallized honey remains unchanged; however, the uncrystallized portion has a higher water content, so it is not suitable for long-term storage and should be consumed promptly. There is no issue with its quality. Therefore, it is not necessary for honey to either crystallize or not crystallize!
In summary, honey crystallization is a physical phenomenon. Its chemical composition and nutritional value remain unchanged, and it does not affect the quality of the honey. The crystals are glucose, not added white sugar, and crystallization does not impact the honey's quality.
However, it is true that adulterated honey with added white sugar can also crystallize. The difference is that white sugar crystals are hard and do not crush easily when rubbed, whereas honey crystals crush easily when rubbed.
What is the white foam on the surface of honey?
The foaming of honey is actually one of the signs and a test method to determine if it is raw, unprocessed, and pure honey.
The reasons why pure, unprocessed honey with no additives or concentration is prone to foaming when shaken:
1. Honey contains 4-7 types of proteins, typically existing as colloidal substances. These are particles in honey that are between molecules and suspended particles and cannot be removed by filtration. The content of this colloidal substance is about 0.2% in light-colored honey and around 1% in dark-colored honey. It affects the color and turbidity of the honey and can cause foaming, but it does not change the honey's quality.
2. Unprocessed honey has strong antibacterial properties. The antibacterial effect of honey is generally believed to be due not only to its high concentration of sugar and low pH value, which inhibit microbial growth, but more importantly, to the production of an antibacterial substance—hydrogen peroxide—from glucose in honey under the action of glucose oxidase! Hydrogen peroxide easily decomposes into oxygen at high temperatures, causing a layer of white foam to appear on the surface of the honey!