When we say food has spoiled, what we really mean is that microscopic invaders have gotten there first. Bacteria, fungi, and moulds are almost always present in small amounts, and much of food preservation is really about keeping these organisms at bay. By that logic, honey should be an easy target—it’s packed with natural sugars that bacteria would normally love. Yet honey defies the rule. Thanks to its unique chemistry, it creates an environment so inhospitable that spoilage microbes simply can’t survive.
So, what makes honey endure for centuries? Let’s break it down.
Reasons Why Honey Never Expires
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Low Water Content
One of the most important reasons honey never spoils is its low moisture content. Most foods contain enough water to allow bacteria and fungi to grow, but honey is different. With typically less than 18% water, it’s simply too dry to support microbial life.
Microorganisms rely on water to survive and multiply. Without it, they become inactive or die off. In this way, honey acts like a desert for microbes—dense, inhospitable, and offering no chance for bacteria or fungi to thrive. This low water activity essentially starves spoilage organisms before they ever get the chance to cause trouble.
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Natural Enzymes and Antioxidants
Honey owes much of its staying power to natural compounds added and preserved by the bees themselves. One key player is an enzyme called glucose oxidase, which bees introduce during the honey-making process. This enzyme slowly generates small amounts of hydrogen peroxide, the same substance we use to disinfect cuts. In honey, it acts as a gentle preservative, discouraging the growth of harmful microbes without affecting the flavour.
But that’s not all. Honey is also loaded with antioxidants such as flavonoids and phenolic acids. These compounds protect honey from oxidation—a chemical process that can make foods lose their flavour, colour, and nutritional value over time. By neutralising free radicals, antioxidants not only help honey retain its golden colour and rich taste but also play a role in preventing it from going bad.
Together, these natural defences—from enzymes to antioxidants—form a powerful shield, keeping honey fresh and stable for years, even centuries.
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High Acidity
Another reason honey resists spoilage is its naturally acidic environment. With a pH that typically falls between 3.2 and 4.5, honey is far more acidic than most foods. This level of acidity is too harsh for the majority of bacteria, fungi, and moulds, which generally thrive in neutral conditions closer to a pH of 7.
The source of this acidity comes from several organic acids within honey, the most notable being gluconic acid. This acid forms as a byproduct of glucose oxidation—a process triggered by the enzyme glucose oxidase that bees add during honey production. The result is a protective environment where spoilage organisms cannot grow or multiply.
By creating conditions that are simply too sour for microbes, honey’s acidity serves as a natural safeguard, ensuring it remains edible and safe for consumption even after years of storage.
How Honey Differs from Other Foods
Most sugary foods—like fruits, syrups, or jams—spoil quickly because they contain enough water for microbes to grow. A ripe fruit, for example, is full of moisture, making it a perfect breeding ground for bacteria and mould. Even jams and syrups, though preserved with added sugar, often need refrigeration or extra preservatives to stop them from fermenting or moulding.
Honey is different. Its low moisture, high acidity, and natural compounds keep microbes at bay, letting it stay safe and edible for centuries.
Misconceptions About Honey
Although honey doesn’t go bad, it can crystallise as its sugars naturally solidify. This is normal and doesn’t indicate spoilage. To restore its smooth, liquid texture, gently warm the jar in hot water or heat it briefly in a microwave—its taste and quality will remain intact.
Tips for Using and Storing Honey
Keep honey at its best by storing it in a cool, dry spot with the lid tightly closed, away from moisture and direct sunlight. Not only does honey last longer this way, but it’s also a healthier alternative to refined sugar, providing natural sweetness along with beneficial enzymes, antioxidants, and nutrients.
Conclusion
Honey’s ability to last for centuries isn’t luck—it’s science. Its low moisture, acidity, natural enzymes, and antioxidants work together to keep bacteria and moulds away. Stored properly, honey remains safe, delicious, and a healthier alternative to sugar.
The fact that honey can last for centuries isn’t magic—it’s the remarkable chemistry perfected by bees.
References:
OneQueen. (no date) Why honey never spoils: the science. Available at: https://onequeen.ro/blog/everything-about-honey/why-honey-never-spoils-the-science/ (Accessed: 15 October 2025).
BBC. (2025) The chemical secrets that help keep honey fresh for so long, BBC Future. Available at: https://www.bbc.com/future/article/20250701-the-chemical-secrets-that-help-keep-honey-fresh-for-so-long (Accessed: 15 October 2025).
Compound Interest. (2014, August 21) The chemistry of honey. Available at: https://www.compoundchem.com/2014/08/21/chemistryofhoney/amp/ (Accessed: 15 October 2025).