There's been a few problems this year with high C4 sugar readings in manuka honey in the whole industry.
Honey that is exported has to pass a whole raft of tests, including normal food-type tests - does it contain poisons such as tutin, does it contain bacteria, does it contain impurities - plus some special honey tests. And testing for adulteration with sugar is one.
In this blog post I talk about ways that manuka honey fraud might happen. Now I don't really want to give a primer on how to beat the system (and my brain is far too pure to even be good at it, heh!), but one other way that honey fraud can happen is adding sugar to honey.
I think the basic motivation to adding sugar is effectively diluting the honey with sweetness, so you make more jars from the same amount of honey.
And you can test for this with the C4 sugar test. If your honey has more than 7% C4 sugar, it fails. Check out Analytica Laboratories excellent description.
Feeding sugar syrup to hives
One way C4 sugar might show up in honey is if the bees have been fed sugar at the wrong time. Especially if the honey is harvested early in the season. Check out Analytica's more in depth report here, if you like the science.
We've had some manuka honey unexpectedly rejected this year too.
So our first question to ourselves was to review our processes. Were we feeding sugar syrup to our hives too close to nectar flow? Or maybe we were feeding sugar to our nucs and they were too close to our productive hives and some robbing was occurring?
Always room for improvement, right?
But nope, all looks pretty good.
So, what else could be going on? And it is a problem that has affected lots of beekeepers this year too, for some reason.
Special manuka honey properties and C4 sugar
Manuka honey initially contains high levels of DHA. Over time the DHA converts to MGO. And MGO gives manuka honey it's magical properties.
But the chemical process of DHA to MGO also messes with the C4 sugar readings. Or so it seems.
I'm paraphrasing wildly here, and the science is not yet conclusive, but if you really want the down and dirty on all this science try these 2 articles 'The Unique Manuka Effect' and 'Adulteration Identification'.
What is 'C4' sugar anyway? (bonus points for science geeks)
Why not just 'sugar'?
Again, the short answer: there are 3 types of ways that nature stores carbon (C) in plants through photosynthesis. Two of them are called C3 from a system called the Calvin cycle, and it produces nectar.
The other method is for producing cane sugar and high fructose corn sugar, as in maize, and is called C4 sugars (system is called Hatch-Slack cycle, don't you love it?).
And you can test for each type. Using, if you must know, isotope ratio mass spectroscopy (IRMS).
And if you are still with me here, perhaps you'd like to write me a little blog post outlining all the technicalities? Contributions always appreciated!
But what we all really want is our honey to not be rejected unfairly. Currently all you can do is mix it with other honey so the levels drop to below 7%, a bit like you do with tutin honey.
I guess the scientists, and hopefully MPI's review of manuka honey will cover some of these issues. Fingers crossed. I seem to be saying that a bit lately.