Honey and Spoilage
Name: George A. J.
Date: 2/19/2003 - Up-dated Fall 2009
I have been told that raw honey will never spoil because
it is hydroscopic. Yet, there apparently is no such word as hydroscopic.
There is hygroscopic, the tendency to absorb water.
Therefore, why does raw honey not spoil? What chemical properties does it
contain that prevents spoilage?
Hydroscopic refers to using lenses in photography under water. Hygroscopic deals
with absorbing moisture.
The nectar brought to the hive by the bees is about 60% water. The bees
"cure" it to about 18-19% water. At this level of water and with a pH of
3-4, the honey is very stable and can last for literally centuries. (It
was found in Egyptian tombs.) However, it is - as you mention -
hydroscopic. (I believe there is such a word.) If it is left exposed to
the air, it will absorb water from the air. The greater concentration of
water allows yeast (that is found naturally in the environment) to
multiply. A by product of the yeast is alcohol - the honey ferments. If
the correct yeast is present (and naturally occurring yeast is not such)
is produces a drink known as mead. If allowed to ferment naturally, honey
develops an unpalatable taste... though it is still sometimes used in
baking where the alcohol is evaporated from the honey.
The bees prevent the fermentation of the honey by sealing the honey in the
honey comb. When we harvest the honey, we can leave it in the comb or
extract it and seal it in jars, like the shelves of your local grocery store.
Because honey is hygroscopic, it is extends the shelf-life of baked
goods. They are less likely to dry out because the honey absorbs moisture
from the surrounding air. If you want to try this out, bake a batch of
cookies using sugar. Then make a second batch replacing half of the sugar
with honey. To do this you need to reduce the liquids in the recipe by
1/4 cup for each cup of honey (because of the water in the honey...
remember, about 19%) and reduce the cooking temperature by 25
degrees. See which batch survives longer.
If you are interested in knowing more, check out - http://honey.com/
Right you are -- the word is hygroscopic. Nevertheless, that is only part of
the story regarding honey's ability to resist spoilage. The high
concentration of sugar in honey -- and its attractiveness to moisture --
makes honey (raw or otherwise) a kind of dehydrating agent. Molds and
bacteria that land on the honey lose their own moisture to the honey, Thus
their growth cycle is compromised and spoilage is reduced.
I do not know why honey does not spoil -- good question -- but there is a
technical word "hygroscopic".
Raw honey can ferment. See this site for some further details.
I am not a honey expert in any way but I will hazard a guess and hope that if
a biologist sees this question, you will get another answer as well. I have
never had honey go bad. I have had it crystallize and have to heat it to get
it liquid again. I would imagine that because honey is mainly sugar, it
will not spoil just like granulated sugar does not spoil. It might get
lumpy, but not moldy or rancid. Perhaps because it is a complex carbohydrate
the bacteria in the air cannot process it.
Anyway that is an answer from a physics person.
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