Honey keeps for years because its low water content makes it a poor home for bacteria.

The longer version

Bacteria and mould need water to grow and reproduce. Honey contains very little of it, and the sugar dissolved in it binds what moisture there is, leaving microbes with nothing usable. Any cell that lands in the jar loses water through its own membrane and cannot multiply.

The liquid is also mildly acidic and contains small amounts of hydrogen peroxide, both of which discourage growth further. Over long storage it may darken or crystallise, but those changes are harmless. Sealed containers matter as well, because honey left open slowly absorbs water from the air and then loses that protection.

Where this entry sits

Everyday physics and chemistry hide small wonders in plain sight, from kitchen reactions to the light in the sky. These short facts explain matter, energy, electricity, magnets, sound, and the simple units we use to measure the world. The full list sits on the Science and Physics page, where every entry is listed in order.

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Pressure cookers raise the boiling point of water so food cooks faster than usual.

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