Jump to content

Recommended Posts

Hey all, I'm a complete newbie to this, can anyone help me understand the C4 testing requirements of honey...does anyone have a good easy to read article or website on the subject? Just trying to understand the practical implications of feeding too much sugar syrup and it being left in the frames come the nectar flow ... how do you manage this and what are the costs for not getting it right.

Thanks

Share this post


Link to post
Share on other sites
Posted (edited)

We've written a bunch of articles about C4 for the Beekeeper, you can find these all here: https://analytica.co.nz/News-Resources/tag/c4-sugars This one here is probably the best 'C4 101' article: C4 Sugars Answers to Commonly Asked Questions (have also attached). Happy to answer any further Qs you have. 

 

This segment of an article written by Karyne Rogers for the Journal of Agricultural and Food Chemistry explains the overfeeding/nectar flow issue well: 

 

Excess Cane Sugar Contamination (Genuine Fail).
Sugar syrups are fed to bees as a supplementary carbohydrate
source in times of winter nectar dearth or to prevent starvation
during poor weather. Sugar syrups are also used to retain bees
in specific areas such as orchards or fields to provide pollination
services or to boost hives into breeding mode several weeks
prior to nectar flow. However, supplementary syrup feeding
also risks overuse, resulting in bees storing excess sugar syrups
into brood boxes, which can later be uncapped and
redistributed into collection boxes by the bees as they make
more room for brood. Cane sugar (a C-4 plant, with a more
positive carbon isotope value than C-3 plants) is the sole bulk
sugar product available in New Zealand for commercial
beekeepers. Addition or mixing of C-4 sugar syrups (which
has a stable carbon isotope or δ13C value of ∼−10‰) with
plant nectar will shift the δ13C honey isotope values to more
positive isotope values than the δ13C values of available C-3
plant nectar sources, which range from −24 to −27‰.

 

Article is: Investigating C‑4 Sugar Contamination of Manuka Honey and Other New Zealand Honey Varieties Using Carbon Isotopes (dx.doi.org/10.1021/jf404766f | J. Agric. Food Chem. 2014, 62, 2605−2614)

C4 Sugars Answers to Commonly Asked Questions_Jul 2018.pdf

Edited by Kate R
added in an extra comment
  • Like 1

Share this post


Link to post
Share on other sites

Thanks, Kate, that explains a lot. I Appreciate the response.

Share this post


Link to post
Share on other sites

No worries. If you're producing non-manuka, overfeeding is the main thing you need to be careful of to keep your C4 sugar levels below the 7% threshold. There are complications with high-grade manuka where the apparent C4 levels in the honey shift over time (increase), and this shift has nothing to do with any addition of sugars to the honey. However, regardless of the grade of manuka, the baseline C4 levels will be higher if overfeeding has occurred. 

Share this post


Link to post
Share on other sites

keep in mind its not just about you feeding the hives.

plenty of cases around of bees robbing other hives that have been fed, spilt sugar or even sweets that have been fed to stock or dumped.

one of the many downsides to over stocking.

  • Agree 1

Share this post


Link to post
Share on other sites
1 hour ago, tristan said:

keep in mind its not just about you feeding the hives.

plenty of cases around of bees robbing other hives that have been fed, spilt sugar or even sweets that have been fed to stock or dumped.

one of the many downsides to over stocking.

Our bees love the Woodstock cans at the recycling depot. 

  • Haha 3

Share this post


Link to post
Share on other sites
Posted (edited)
10 hours ago, Kate R said:

 the main thing you need to be careful of to keep your C4 sugar levels below the 7% threshold. 

 

Katie i was told (from an unreliable source), that this number 7 is not a percent, but some other kind of calculation. Could you confirm as an expert, that it is definately 7% ?

 

IE, 7% of what? Would it be of the honey in the sample jar, 7% of it is sugar syrup? Or 7% of total sugar is C4 sugar, or what?

 

I would just like to know how this works.

.

Just to explain the question better and in the way a beekeeper would see it. If there is a super full of honey, but 7% of it is actually sugar syrup that the bees have processed and stored, would that equal 7% C4 in the test? In non manuka honey.

Edited by Alastair

Share this post


Link to post
Share on other sites
Posted (edited)
Quote


The C4 sugar test analyses the ratio of the two most common isotopes of carbon (12C and 13C) in both the whole honey and the protein which is precipitated out of the honey using isotope ratio mass spectroscopy (IRMS).
The ratio of 13C/12C is different in honey produced from nectar (which comes from
C3 plants) compared to cane sugar or high fructose corn syrup (which come from C4 plants). The basic principle of the C4 sugar test is that if honey has not been adulterated with additional sugar, the ratio of 13C/12C in the whole honey and the protein precipitated from that honey will be very close. However, if sugar has been added, the ratio of 13C/12C will be different in the whole honey and the protein. Internationally it is accepted that
the difference in the ratio of 13C/12C between whole honey and protein (also called δ13C)
in unadulterated honey will be less than or equal to 7%.

 

@Alastair An article that was in the Beekeeper magazine by Megan Grainger from Analytica.

I figure If I can understand it then most people can understand it.

 

I read somewhere recently that  invert sugar syrup has a much greater c4 than regular syrup like up in the high 20’s. I imagine that could cause a few headaches. 

Edited by frazzledfozzle
  • Thanks 1

Share this post


Link to post
Share on other sites
Posted (edited)
On 31/05/2019 at 6:50 PM, Alastair said:

 

Katie i was told (from an unreliable source), that this number 7 is not a percent, but some other kind of calculation. Could you confirm as an expert, that it is definately 7% ?

 

IE, 7% of what? Would it be of the honey in the sample jar, 7% of it is sugar syrup? Or 7% of total sugar is C4 sugar, or what?

 

I would just like to know how this works.

.

Just to explain the question better and in the way a beekeeper would see it. If there is a super full of honey, but 7% of it is actually sugar syrup that the bees have processed and stored, would that equal 7% C4 in the test? In non manuka honey.

 

The result is a percentage but it's not a direct measurement of the sugar as a concentration in the same way you'd interpret, for example, a 3in1 result. Unfortunately it's a bit more complicated than that. As frazzled has explained in that excerpt from one of our Beekeeper articles, the C4 test is comparing ratios of two different carbon isotopes (carbon-12 and carbon-13) in the honey and also in a measurement of the protein in the honey. The basis of this is that carbon ratios in sugars from nectar (C3 sugars) will be different from carbon ratios in sugars from other sources such as sugarcane, corn, etc. (C4 sugars).  When you calculate the difference between the honey and the protein measurements this gives you the % C4 Sugars.

 

If no C4 sugars have been added to the honey, you can expect the carbon ratios in the protein and the honey to be almost exactly the same. If C4 sugars have been added, the carbon ratio in the honey will differ from the protein (think of the protein as an indicator of the "true" carbon ratio of the honey). The AOAC standard for C4 sugars allows for a %C4 Sugars of up to 7% to allow for natural variation in that protein measurement (it's biology, so the protein won't be the same from honey to honey.) It's for this reason that you can get results in the negatives e.g. -7% C4 Sugar - which doesn't make sense. This is probably what your source was referring to where, less than 7% C4 is an indicator of 'apparent' C4 sugars i.e. regardless of a result between 0 - 7%, there could be no C4 sugar, and where greater than 7% C4 sugars according to the AOAC standard indicates adulteration.

 

On 1/06/2019 at 8:04 AM, frazzledfozzle said:

I read somewhere recently that  invert sugar syrup has a much greater c4 than regular syrup like up in the high 20’s. I imagine that could cause a few headaches. 

 

If the invert sugar syrup is from a C4 plant (e.g. sugarcane), regardless of whether it is invert or not, the sugar will be 100% C4 sugar. The difference in result you get when you test the honey is likely due to how much the bees have stored from the hives you've collected the honey from. 

 

I've attached that Karyne Rogers article I mentioned that you might find interesting. It discusses causes for C4 sugar fails including excess cane sugar contamination (e.g. overfeeding), supplementary protein feeding, brood box contribution, etc.  

Investigating C‑4 Sugar Contamination of Manuka Honey and Other New Zealand Honey Varieties Using Carbon Isotopes, Rogers 2014.pdf

Edited by Kate R
font sizes were all different..!
  • Good Info 1

Share this post


Link to post
Share on other sites

Thanks Kate, appreciate your full explanation. 🙂

Share this post


Link to post
Share on other sites
Posted (edited)
On 5/06/2019 at 9:37 AM, Kate R said:

 When you calculate the difference between the honey and the protein measurements this gives you the % C4 Sugars.

 

Actually the original research on this by Johnathon White determined this relationship by blending known concentrations of C3 and C4 sugars and measuring the differences between the protein C13 levels and the blended honey and C4 sugar values.  The calculations in the current method are based on this calibration work and are not a result of the actual measurements.

 

In the real World there is some significant difference at times between the protein C13 and total honey C13 ratios, the most obvious is when the measurements deliver a negative value for C4 sugars.

 

Different C3 plants can have a wide range of C13 values and this is enough of a range for the single C13 measurement to be of little value for spotting adulteration.  e.g. a 50:50 blend of some C3 and C4 sugars could pass as a C3 signature.  Hence the development of using the protein as an internal standard.  The original paper posits that the protein in honey is mostly enzymes from the bees, and the bees have fed on the same source material that the nectar is produced from, so this protein should have the same C13 signature as the nectar/honey.  Over a whole season of honey production this is likely to be mostly true, but for crops in the early spring like manuka, the bees have fed and grown on pollen prior to the manuka nectar flow that may have a different C13 signature.

 

And Karyne Rogers showed (The Unique Manuka Effect: Why New Zealand Manuka Honey Fails the AOAC 998.12 C‑4 Sugar Method) that when you added DHA to clover honey, the C13 signature of the protein (the internal standard) changed with time.  It is probable that the MG in the resulting mix chopped up some of the protein.  This meant that the apparent C4 sugars increased, i.e. an impossibility and thus an artifact and failure of the test.

 

But because economic adulteration of honey by other syrups is (in some quarters) considered the number one problem causing an oversupply of honey in the World, don't expect the C4 sugar test (SCIRA - Stable Carbon Isotope Ratio Analysis) to be cast on the scrap heap any time soon.

Edited by Emissary
  • Good Info 4

Share this post


Link to post
Share on other sites

@Emissary Ah yes, all good info thanks for sharing! Thanks for elaborating more RE my comment on the percentage difference, I didn't intend to simplify it down too much but thank you for clarifying. Absolutely the apparent C4 sugars is a real issue of the test and its suitability for use on manuka. I know that work funded by UMFHA using radiocative 14C isotopes showed that DHA and MG bind in significant amount to the protein, not sure if it's been proven that the protein is getting broken down in anyway. This particular work suggested a 'factor X' with a negative δ13C may also be binding to the protein and causing this shift in the protein measurement. 

  • Good Info 1

Share this post


Link to post
Share on other sites

The big question i would like to know, is this.

 

Last spring i over fed some hives with sugar then the flow immediately started, i added boxes, and some hives moved sugar up into the honey supers to clear room for brood. The syrup could be seen in some of the combs. So i marked the suspect supers and at harvest time took them all as a seperate batch, to not contaminate any of the other honey.

 

I was fully expecting this batch of honey to have a C4 of over 7, but it was under. Is it possible to eyeball an amount of sugar syrup in a super, and roughly translate that into what it would translate into at the C4 test?

Share this post


Link to post
Share on other sites

In other words, literally seeing what you can get away with ?  😀

Share this post


Link to post
Share on other sites

One way of putting it.

 

Share this post


Link to post
Share on other sites

how many kilo's of sugar can we get away with in our honey?

thats the main question we need answered.

 

 

Share this post


Link to post
Share on other sites

I think Apimondia would contest none..! https://www.apimondia.com/documents/apimondia_statement_on_honey_fraud.pdf  Although the sugars may not be detected with the C4 test, the risk is it could be picked up with other tests available internationally. 

 

See under: Table 1: Modes of honey production that violate the Codex Alimentarius Standard

 

Feeding bees during a nectar flow. - Honey can only be produced by honey bees from the nectar of plants or from secretions of living parts of plants or excretions of plant-sucking insects on the living parts of plants.

  • Good Info 1

Share this post


Link to post
Share on other sites
22 minutes ago, Kate R said:

I think Apimondia would contest none..!

the reality is some frames of sugar feed get moved into supers and is not always consumed before honey flow starts. to avoid that your often feeding up to the start of the honey flow which is easy to be caught out. however the sites that we have had fail on sugar (and others reported the same) is sites that have been robbing out other beeks feeding operations. thats the downside of high density beekeeping. 

  • Agree 1

Share this post


Link to post
Share on other sites

Seems to me this feeding business is fraught with risk, and best avoided, particularly when most honey crops aren't worth much.

  • Haha 1

Share this post


Link to post
Share on other sites
Posted (edited)
1 hour ago, tristan said:

the reality is some frames of sugar feed get moved into supers and is not always consumed before honey flow starts. to avoid that your often feeding up to the start of the honey flow which is easy to be caught out.

 

Karyne Rogers tested over 700 samples of "pasture" honey and virtually none failed the C4 test.  The circumstance of feeding right up to the flow waiting for the hive to become self sufficient is common or routine, and certainly not peculiar to manuka production.  Strong hives quickly starve without feed, and broken weather can cause that in less time than it takes to get round your operation.  So why do only manuka samples fail? 

 

This quote from the orignal paper "Honey Protein as Internal Standard for Stable Carbon Isotope Ratio Detection of Adulteration of Honey" JONATHANW. WHITE, KENNETH WINTERS is perhaps an explanation as to why all those pasture samples passed.

 

"Before a honey flow, particularly in early spring, it is common practice to built up colony strength by feeding sugar syrup; HFCS as well as sucrose or invert sugar is used. The protein  (enzymes) added by the bees to stores during this period would reflect the isotopic composition of that feed." (sic)

 

This implies that the C13 signature of the bees and their protein moves to that of the carbohydrate feed (in this case C4 sugars) and thus not produce a "fail".   I have some question about this hypothesis because the protein from bees is mostly produced from their pollen source and not the carbohydrate source.  Perhaps in metabolising the protein, they are incorporating C13 from the supplemenatry feed.

 

Another consideration is the dilution effect.  Bees consume 90-95% of the carbohydrates they collect annually.  So a hive producing 30kgs of honey (national average) will have collected and consumed an additional 270-570 kgs of carbohydrate  - including sugar fed syrup.  5 - 10 kilos of sugar is a small proportion of that amount.

 

It would seem that non manuka honey has always passed and manuka routinely fails.  And the manuka is known to fail from the DHA/MG mechanism.

I'm not saying you couldn't do something to make non manuka fail with prodigious amounts of sugar feeding on a flow, but the question here is about fails with "normal" beekeeping practises.  If you feed your bees with a safety margin of sugar right up to a flow like most all do in the country (and the US), then for non manuka you are very unlikely to have a problem.

 

For manuka you will have a problem regardless of your sugar feeding regime.  And likely more of a problem with more sugar feeding, but why this is exactly is not well understood.

Edited by Emissary
  • Agree 1
  • Good Info 1

Share this post


Link to post
Share on other sites
Posted (edited)
58 minutes ago, Emissary said:

"Before a honey flow, particularly in early spring, it is common practice to built up colony strength by feeding sugar syrup; HFCS as well as sucrose or invert sugar is used. The protein  (enzymes) added by the bees to stores during this period would reflect the isotopic composition of that feed." (sic)

 

This implies that the C13 signature of the bees and their protein moves to that of the carbohydrate feed (in this case C4 sugars) and thus not produce a "fail".   I have some question about this hypothesis because the protein from bees is mostly produced from their pollen source and not the carbohydrate source.  Perhaps in metabolising the protein, they are incorporating C13 from the supplemenatry feed.

i highly doubt that implication simply due to beeks failing the test on non-manuka honey from sites that are next to nucs sites that are constantly being fed, ie robbed.

 

for us up here manuka is the first crop, so thats the one that has any left over sugar from feeding. 

Edited by tristan

Share this post


Link to post
Share on other sites
Posted (edited)
4 hours ago, Emissary said:

 

Karyne Rogers tested over 700 samples of "pasture" honey and virtually none failed the C4 test.  The circumstance of feeding right up to the flow waiting for the hive to become self sufficient is common or routine, and certainly not peculiar to manuka production.  Strong hives quickly starve without feed, and broken weather can cause that in less time than it takes to get round your operation.  So why do only manuka samples fail? 

 

This quote from the orignal paper "Honey Protein as Internal Standard for Stable Carbon Isotope Ratio Detection of Adulteration of Honey" JONATHANW. WHITE, KENNETH WINTERS is perhaps an explanation as to why all those pasture samples passed.

 

"Before a honey flow, particularly in early spring, it is common practice to built up colony strength by feeding sugar syrup; HFCS as well as sucrose or invert sugar is used. The protein  (enzymes) added by the bees to stores during this period would reflect the isotopic composition of that feed." (sic)

 

This implies that the C13 signature of the bees and their protein moves to that of the carbohydrate feed (in this case C4 sugars) and thus not produce a "fail".   I have some question about this hypothesis because the protein from bees is mostly produced from their pollen source and not the carbohydrate source.  Perhaps in metabolising the protein, they are incorporating C13 from the supplemenatry feed.

 

Another consideration is the dilution effect.  Bees consume 90-95% of the carbohydrates they collect annually.  So a hive producing 30kgs of honey (national average) will have collected and consumed an additional 270-570 kgs of carbohydrate  - including sugar fed syrup.  5 - 10 kilos of sugar is a small proportion of that amount.

 

It would seem that non manuka honey has always passed and manuka routinely fails.  And the manuka is known to fail from the DHA/MG mechanism.

I'm not saying you couldn't do something to make non manuka fail with prodigious amounts of sugar feeding on a flow, but the question here is about fails with "normal" beekeeping practises.  If you feed your bees with a safety margin of sugar right up to a flow like most all do in the country (and the US), then for non manuka you are very unlikely to have a problem.

 

For manuka you will have a problem regardless of your sugar feeding regime.  And likely more of a problem with more sugar feeding, but why this is exactly is not well understood.

I don't understand the mechanism, but I think it is almost certain that some high C4 sugar results in Manuka have little  to do with sugar syrup feeding, and most high C4 for sugar results in Kanuka have little to do with feeding sugar syrup.  For us in the Far North Kanuka is a second, totally separate crop.  Manuka boxes come off, and the Kanuka boxes go on, yet some years, like this year, when we had an amazing Kanuka flow in our area, and ended up with a very big crop, of very pure Kanuka- had a 3-PLA level of 3100mg/kg(3-PLA is an amazing Kanuka marker making it worse than useless as a Manuka Marker IMHO), yet, virtually everyone had highish C4 sugar results, and it is almost impossible for those results to have had anything to do with sugar syrup feeding.

Edited by David Yanke
  • Agree 2
  • Good Info 2

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...