Generally sugar solutions when opened and left standing becomes “spoiled” in time. Why can honey be left unrefrigerated and not spoil?
I think it has to due with the honey’s source. Honey isn’t just sugar water, it’s bee vomit! Because of this, it has all sorts of enzymes and such that inhibit bacteria and mold from growing.
Weird, I just got done copy editing a story about honey. Here’s what I learned:
During the honey-making process, honeybees produce enzymes that convert some of the sugar in the nectar into hydrogen peroxide and gluconic acid. Peroxide kills off bacteria and other microbes that might attack the honey while it’s still in the hive, while gluconic acid lowers the pH of the final product. Since molds and such don’t grow well in acidic environments, this helps keep honey fresh after it’s ripened and sent to its final resting place inside the plastic squeezy bear on your breakfast table.
-alan
Honey is a ~60-65% solution of sugars. This puts a tremendous osmotic stress on any bacteria/molds that find their way into it. The cells are killed by the loss of internal fluids to the “dry” environment. Diluting the honey 1:1 with water will allow all sorts of microscopic beasties to thrive in it.
Thanks one and all for the above info. Fascinating!
I might add that the osmotic pressure of the high sugar concentration is why jelly and jam keep so well, even if you don’t refrigerate them. Sure, there’s a lot of nutrients in smashed fruit, but that’s a lot of sugar there, too much for most micro-organisms to live in.
However honey can contain C. botulinum spores which isn’t dangerous for children or adults, but can cause infant botulism. Honey should never be fed to babies under a year old for this reason.
So that’s why you shouldn’t feed honey to hummingbirds in their feeder… Squink’s post mentions diluting it (so the little birds can lick it up) will lower the osmotic gradient enough so that the fungus or mold that is dangerous to hummingbirds can grow. I was somewhat confused by idea that mold grows in honey-water and is bad for hummingbirds while at the same time honey it’s self doesn’t grow bacteria or mold - Neat!