Honey does not expand when it freezes in the way that water does. Its high concentration of sugar, typically around 80%, and low water content prevents it from forming the rigid, crystalline ice structure that causes expansion in pure water. When subjected to cold, honey simply becomes extremely thick and viscous, turning into a semi-solid or glass-like mass rather than a true solid ice block.
The Science of Honey at Low Temperatures
Honey’s resistance to freezing is explained by freezing point depression. The large quantity of dissolved sugars, primarily fructose and glucose, acts like a natural antifreeze, drastically lowering the temperature required for solidification. While pure water freezes at 0°C (32°F), honey’s freezing point can be as low as -40°C (-40°F), a temperature far colder than a standard home freezer can achieve.
The small amount of water present in honey is not free to form a typical ice lattice because it is chemically bonded to the sugar molecules. Instead of freezing, honey becomes highly viscous and may enter a supercooled state or a glassy, amorphous solid state at very low temperatures. At standard freezer temperatures, usually around -18°C (0°F), honey will solidify into a thick, tacky texture that remains scoopable. This thickening is a change in viscosity, not a phase change to a crystalline solid like frozen water.
Volume Change and Density When Chilled
A defining feature of water is that it expands when it freezes, which is why a bottle of water can burst in a freezer. Honey, conversely, behaves like most other liquids when cooled, meaning it contracts slightly and becomes denser as its temperature drops. Any expansion that occurs due to the freezing of its minor water content is negligible and does not pose a threat to its container.
The slight contraction of the sugar solution usually counteracts the minor expansion of the water component, resulting in virtually no overall volume increase. This lack of expansion is why beekeepers and manufacturers can safely freeze honey in glass jars without concern for breakage. Crystallization, or granulation, is often confused with freezing, but this process involves the glucose separating from the water and forming small sugar crystals, which also does not cause significant container expansion.
Optimal Storage Practices for Honey
While freezing honey is safe and an excellent method for long-term preservation, it is not necessary for short-term storage. Honey’s low water content and natural acidity give it an indefinite shelf life at room temperature. The ideal range for everyday storage is generally between 18°C and 24°C (64°F and 75°F). Refrigeration is typically discouraged because temperatures between 10°C and 15°C (50°F and 59°F) accelerate the undesirable process of crystallization.
If honey does crystallize, it is still perfectly safe to consume and can be easily returned to a liquid state. The best method is to gently warm the sealed container in a water bath kept below 40°C (104°F) until the crystals dissolve. When choosing a container for any storage method, it is important to use an airtight seal, as honey is hygroscopic and will absorb moisture and odors from the surrounding environment.