How to determine the purity of honey
I received the following from a reader. His comments and questions are so relevant to the discussion of pure honey that I decided to expand on them.
How do you test that the orange blossom honey is really from oranges? Well, you can look at the pollen present in the honey. But that is a very troublesome process. Is there an easier way?
Similarly, corn syrup is very cheap. Honey is much less cheap. How do you detect that corn syrup has not been accidentally added to your honey? I am told that looking at the HMF (hydroxymethylfurfural) profile to identify the changed state of the fructose is the only way. I wonder if there is any other approach?”
As to the first question, as far as I am aware, the only way of positively identifying the source of honey is by analysis of the pollen grains found in the honey. As I mentioned in an earlier post, however, a person accustomed to eating a particular honey variety may simply recognize it by taste.
For example, I can easily recognize a strongly-flavored honey like buckwheat or gallberry. But give me a honey that is very mild or one that I never tried before and the identification is “iffy” at best—and more likely impossible.
This past weekend, my daughter and I bought two varietal honeys that we had never tasted. We were at Pike Place Market in Seattle and a vendor there had many obscure varietals in tiny jars for $3.50 each. Just for fun we selected two: Japanese knotweed and snowberry.
We brought these back home and did a taste test. Hmm. They tasted different from each other, so I guess that’s a good thing. I know Japanese knotweed is a recognized variety and I’ve read about it from time to time. I described this particular sample as “citrusy.” My daughter said it had a minty coolness to it, without the minty taste. But was it knotweed? Who knows? It could be anything.
I was even more skeptical about the snowberry. I see snowberry growing from time to time, but never in large patches. I’ve never heard or read about snowberry providing a harvestable crop of honey either. That’s not to say it doesn’t happen, but I’ve never heard of it.
We both thought the snowberry tasted pleasant but non-descript. Its texture was different from the knotweed, however. It had the high-fructose velvety smoothness that you get in gallberry (or in a spoonful of corn syrup) but without a really distinct flavor. It tasted like . . . well . . . honey.
From my personal honey-tasting experience, I would conclude that both the samples were pure honey, but whether they actually came mainly from knotweed and snowberry is anybody’s guess.
Because I have no intention of trying to identify the pollen in my two samples, I will never really know what is in them. However, having tasted a lot of honey, I trust that they contained no added sugars. In fact, I wouldn’t expect to see added syrup in honey sold as a varietal, but to find it more often in honey that is sold for processing into other products such as breakfast cereal or candy bars—places where it would be very easy to hide a little corn syrup.
As for the second question, corn syrup or cane sugar can be identified in honey samples by looking at the ratio of the stable isotopes of carbon. Most plants that originated in the northern hemisphere are known as C3 plants, whereas many of the grasses, especially those originating in hot, dry climates are known as C4 plants. These two types of plants contain different ratios of carbon-13 and carbon-14 isotopes. So by studying the ratios of carbon isotopes in the honey, you can tell if it has been adulterated by one of the grasses—either corn or cane. However, this method doesn’t work for honey adulterated by beet sugar. Sugar beets, which are not a grass, have a C3 profile.
Although a purchaser of bulk honey may pay for a stable isotope analysis to determine the purity of the honey, the average consumer is not in a position to do so. So, at least for now, you have to trust your beekeeper or your taste buds to determine if your honey is pure.
 An isotope is a form of an element with extra neutrons in the nucleus. These extra neutrons make the element heavier than normal—so they are easily detected. Unstable isotopes decay and are radioactive, whereas stable isotopes do not decay and are not radioactive.