In 2015, archaeologists reported that they'd found 3,000-year-old honey while excavating tombs in Egypt, and it was perfectly edible .

This durability is thanks to the unique features of honey: it is low in water and high in sugar, so bacteria cannot grow on it.

Honey also contains small amounts of hydrogen peroxide, which inhibits growth of microbes. This is partly why bees produce it for the young in their hives – it is both food and protection.

Processing honey also helps as the sugars in honey are hygroscopic and tend to draw in atmospheric water, which is not ideal. However, during processing and packaging, the heat treatment first removes water and then airtight lids keeps the water out, helping it keep for longer.

Although honey can go cloudy and crystallise when opened as the sugars draw in water again, this physical change can be reversed by simply warming the honey.