The conversion of the watery nectar to syrupy honey takes between days. Honey also has a low water activity; this is a measure of the amount of water in a substance that is available to support microbial growth.
Water activity is on a scale of 0 to 1, with most moulds and bacteria being unable to grow under a water activity of 0. Honey has a water activity of 0. This, combined with the fact that its low water content dehydrates bacteria, makes it resistant to spoiling. Another factor that helps honey avoid spoiling is its acidity.
Its average pH is around 4; this acidity is contributed to by a number of acids, including formic acid and citric acid, but the dominant acid is gluconic acid, produced by the action of bee enzymes on some of the glucose molecules in the honey. Hydrogen peroxide is also produce by the production of gluconic acid — this too can inhibit the growth of bacteria. On a final note, you might also notice that, over time, honey tends to crystallise and solidify.
Over time, glucose will precipitate out of the solution, forming solid crystals. Hungry for more food and drink chemistry? Check out the Compound Interest book! This is why honey is effective as a quick dressing on a cut. Because the water content of honey is so low, the sugar glucose eventually comes out of solution as solid crystals. The glucose is said to be a precipitate.
Even though this happens, the honey is still fine to eat and not technically spoiled. All you have to do to get it back to the form you want is immerse it in a little warm water for a few minutes. This is also the same reason you should not leave a jar of honey uncovered. The solution will absorb moisture from the air. As it does, it gradually loses its antibacterial properties and will then spoil.
One last note. You may know that infants should never be given honey. The reason is that honey sometimes contains inactive spores of the bacterium that causes botulism.
Botulism is a food-borne illness can be life-threatening. 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.
As with honey, the key to a long shelf-life is processing and storage. Also, any enzymes that would naturally break down the product after harvest are put into suspended animation. If the container is airtight, they will last for years and still be a great source of protein. If you allow water in, however, then they will only last a few months. Soy sauce has the potential to last at least three years.
Does Honey Go Bad or Expire? By Kait Hanson Updated February 04, Pin FB Share. When it's stored properly, honey never goes bad, Grad said in an interview with Allrecipes. Credit: Big Island Bees. All rights reserved.
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