Everyday
Does honey ever go bad?
The short answer
Sealed honey does not spoil. Archaeologists have recovered pots of honey from ancient Egyptian tombs, sealed for over 3,000 years, still edible. Three things do it: almost no water, an acidic pH, and hydrogen peroxide produced by an enzyme from the bees.
The first defence is dryness. Honey is essentially sugar, and sugar is hygroscopic — it pulls moisture out of everything around it, including any bacterium unwise enough to land in it. Untouched honey contains almost no free water, and very little can live in that.
The second is acidity: honey's pH sits somewhere between 3 and 4.5, low enough to see off most of what survives the dryness. The third comes from the bees themselves. An enzyme in the bee's stomach, glucose oxidase, converts nectar into gluconic acid and small amounts of hydrogen peroxide.
The seal is the condition everyone skips. Honey stays good as long as the lid is on and no water gets in. Leave it open in a humid kitchen and it will happily absorb moisture from the air and ferment. The Egyptian pots were sealed — that is why they are still lunch.
Source
- The Science Behind Honey's Eternal Shelf LifeSmithsonian Magazine