Honey Keeps for Years Because It Is Thirsty
Honey is one of the few foods that can sit in a cupboard for a very long time without spoiling. A jar opened years ago can still be safe to eat, which surprises many people. The secret is in what honey is made of.
Honey is mostly sugar, with only a small amount of water. Germs that spoil food, such as bacteria and molds, need water to grow. In honey the sugar holds on to the water so tightly that very little is left for them to use. A germ that lands in honey tends to dry out and stop growing.
Bees help, too. When they turn nectar into honey, they fan it with their wings so extra water evaporates, and they add a substance from their bodies that changes the nectar. Then they seal the finished honey inside wax cells.
Honey does change with age. It may darken, or form crystals that make it look cloudy and grainy. That is only the sugar settling into solid grains, and warming the jar gently in a bowl of warm water makes the honey smooth again. The one important rule is to keep the lid on tight. Honey soaks up water from damp air, and if it takes in too much, it can begin to ferment.