A teaspoon of honey sweetens hot tea at a near-boil, but boiling honey itself is not a good idea. High temperatures exert a negative impact on almost every aspect of what makes honey such a delicious and nutritious gift of nature. Aside from lessening the appeal of its color, fragrance and flavor, boiling honey destroys the natural properties that can allow it remain unspoiled for literally thousands of years.
Visible Crystals Dissolve
Honey is made mostly of glucose, fructose and water. The proportion of glucose to fructose determines how quickly honey will crystallize. Honey with higher levels of glucose crystallizes more quickly, because glucose molecules tend to separate from water molecules faster than fructose molecules do. Once crystals start to form, they keep forming throughout the honey, making it cloudy and giving it a grainy or paste-like texture. Boiling honey dissolves the crystals, though they actually start to dissolve long before the honey reaches its boiling point.
Texture and Color Change
Water evaporates from boiling honey. Since honey contains approximately 70 percent sugar and less than 20 percent water, there isn't much to spare. As the water evaporates, the honey thickens as does any syrup when liquids boil off. Because boiling concentrates the honey, doing so will also cause it to become darker and less translucent.
Raw and unfiltered honeys contain useful enzymes that break down sugars. This is why honey has been used since ancient times as a digestive aid. Honey also contains potent antimicrobial, antibacterial and antifungal properties. Some types of honey, such as Manuka honey, are so valuable in fighting bacteria that hospitals are testing it to fight methicillin-resistant staphylococcus aureus, or MRSA, the superbug that has become resistant to penicillin and other antibiotics. Boiling honey can weaken or destroy these powerful enzymes, not only lessening their health properties but making the honey more likely to develop bacteria or mold, and become unsafe to consume.
Flavor Intensity Lessens
Much of the flavor in honey comes from the volatile oils in the nectar of the plants sampled by the bees that created it, which is why clover honey has a different flavor from lavender, orange blossom or Tupelo honey. These essential oils are delicate and easily broken down, so boiling honey can weaken the aroma and lessen its luscious, natural flavor.