Short answer: Honey crystallises when some of its natural glucose separates from the liquid and forms crystals. It is a normal physical change influenced by sugar balance, temperature and tiny natural particles such as pollen—not evidence that the honey has spoiled.
The natural crystallisation process
Honey is a concentrated solution of natural sugars. Over time, glucose can come out of solution and form crystals. Different floral honeys crystallise at different speeds because their natural sugar ratios and composition vary.
The crystals may be fine and creamy or larger and more noticeable. Both can occur in genuine honey.
Does crystallisation mean poor quality?
No. Crystallisation is not, by itself, a sign of spoilage or adulteration. It changes texture and appearance, but many people enjoy crystallised honey as a spread because it is less likely to drip.
Unusual fermentation odours, pressure or other signs of contamination are separate issues. If a jar seems damaged or abnormal, contact the seller rather than relying on crystallisation alone.
How to gently liquefy crystallised honey
Place the closed jar in warm water and allow the crystals to soften gradually. Avoid intense direct heat or boiling the honey, which can darken it and change its flavour. Stir gently with a clean, dry utensil if the package instructions permit.
Storage habits that help
Keep the lid tightly closed, avoid introducing water, and store honey in a stable, cool and dry place away from direct sunlight. Refrigeration is generally unnecessary and can encourage crystallisation in many honeys.
Sources and further reading
Information notice: This article provides general food and product information, not medical advice. Honey is not suitable for infants under 12 months; see Healthdirect's infant safety information.