Most pure honey will, in time, go solid or semi-solid. This is known as granulated or crystallized honey. It has not gone bad! The wonderful thing about good quality honey is that it never spoils honey over 2000 years old has been removed from the Egyptian Pyramids and was still edible!
Granulation is natural. It happens when glucose, one of three main sugars in honey, precipitates out of the supersaturated honey solution. The glucose loses water and takes the form of crystals. These crystals then form a lattice which immobilizes other components of honey in a suspension and so creating the semi-solid state.
Granulation is influenced by many things.
1) It depends primarily on the glucose content and moisture level. Honeys with a moisture content of less than 17% are more likely to granulate than those with content closer to 20%.
2) Floral source of honey has a great deal to do with the process. Ivy honey granulates rapidly (a few weeks), heather honey never. The overall composition of honey, which includes sugars other than glucose and more than 180 identified substances such as minerals, acids and proteins, influences crystallization.
3) Temperature plays a major role. Honey granulates most rapidly between 55 and 65 degrees and temperature changes accelerate the process.
4) Crystallization can also be stimulated by any small particles of dust, pollen, bits of wax, propolis or air bubbles that are present in the honey.
5) The more honey is moved around (agitated) the more rapidly granulation will occur.
6) How the honey is handled and processed, storage conditions, temperature, relative humidity and type of container may also influence the tendency of honey to crystallize.
Store honey in a freezer if it is not to be used for a long period of time (months) as this will keep it fresher and reduce the chances of granulation. Otherwise, store and use honey at room temperature.
To return granulated honey to a liquid state
The secret is to use a little heat, enough to re-liquefy it without overheating 130 degrees is all it takes.
Avoid overheating as heat can adversely affect the flavour of honey.
There are two ways to do this:
1) Microwave open the container and use short bursts (30 seconds), wait 20 seconds between bursts, this will keep it from overheating and give you a chance to see the affect. Once honey starts warming up closing the container and shaking will help to dissolve the crystals.
2) Warm water open the container and place in a water bath of 130 degree water (as warm as you can keep a finger in it). Let it stand for about an hour. Repeat if needed.