Refractometer calibration using golden syrup

I would like to humbly suggest the use of golden syrup (you know who makes it…) for calibration of refractometers.

Olive oil is all very well, but how do I know that my bottle of olive oil is quite as virginal as yours? More likely it is from a completely different country, a very different optical index, and possibly a very different definition of 'virgin'!
My point is that golden syrup (partially inverted refiners syrup if you prefer the full name) is subject to extensive quality control and should be the same from Lands End to John O'Groats.
It's also cheap, readily available in most kitchens, and nicer to lick off your fingers than olive oil.

My refractometer measured several samples at a uniform 79.5 Brix.
I accept that because my refractometer was calibrated using olive oil that this value is rather arbitrary, so I would invite anyone who has a refractometer they believe is properly calibrated to test some golden syrup and report back.

I think there was one poster who was ecstatically besotted with calibrating with distilled water. HM Honey IIRC. Perhaps a PM to him would cast some authority on the subject.

Here is a link to the thread:

http://www.beekeepingforum.co.uk/showthread.php?t=29464&page=2

There again, perhaps it wouldn't.

Invert syrup is probably as good as anything - just work to the analysis on the actual jar, but nothing wrong with olive oil - it is quite a stable standard. Honey water content to the nearest half percent is close enough for me.

Syrup is certainly easier to wash off the refractometer plate and cover.

RAB

A large supplier (T*****s) says...
An aid to calibration. Using medicinal liquid paraffin smear a small amount on the prism. This should calibrate to 24.5% on the water scale. Once the refractomter is set/adjusted to this figure all honey samples will also show the correct water content.
Haven't got one yet but this is the only readily available thing I have seen suggested.

Ray

Ah - I think the problem with distilled water is that the cheap flea bay refractometers only go down to 58 Brix (or 27% water) so it does not register on the scale.

I tried some liquid paraffin I found in the shed the other day (not internally) and got some very strange results… hence the search for other standards. I believe T*****'s specify medicinal paraffin - I might have the greenhouse sort!

I would still contend there are enough types of paraffin (and olive oil) of different refractive indexes around to mean that golden syrup could be used as a sensible alternative (especially within the fairly broad limits we require for honey).

If even a few beeks could give us their own readings for golden syrup, a sample mean could be calculated (fairly reflective of a true value) which would be entirely adequate for our purposes.

And you can put it on your porridge.

barneyward said:

And you can put it on your porridge.

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I only put honey on mine

Ah - I think the problem with distilled water is that the cheap flea bay refractometers only go down to 58 Brix (or 27% water) so it does not register on the scale.

Well done, you spotted the flaw!

It works for my 0 - 20 degrees Brix, but not for the honey version.

Other people's results will not really help any individual using invert sugar as a standard. You either accept the nutrition label on the jar or not.

The reason for the oil standard is that it is stable, nothing more. If it gives a result of 'x' now, it should give that same result in two years time. Then, assuming it is correct now, it will be correct when checked in the future. Nothing ore, nothing less. If it were wrong now, it would be wrong in the future, so simply a stable standard, nothing else.

There are different invert syrups out there with different sugar contents. Even 'late & tyle' values are different for tins and squeezy tubes of the stuff.

I would suggest there are innumerably more versions of olive oil out there than there are golden syrup. Each individual oil may be totally stable long-term, but which one do you have to begin with?

On a serious note I agree with you, but it would be useful to know what values others get for golden syrup.

but which one do you have to begin with?

ANY, it doesn't matter a .... hoot. As long as it is stable.

I don't think you really understand the reason for the standard oil.

82.5 but can't guarantee mine is calibrated right! Worth a try!
E

Barneyward,

The idea is that you buy some oil when the device is shiny and new. You hope that the device has been correctly calibrated at the factory and that the courier has not dropped it.

You KEEP some of that original oil for as long as you keep the instrument. You look after it as it is your only way of calibrating your device.

You check the calibration of the new, shiny device and write down the reading.

When you need to re-calibrate you use some of that ORIGINAL oil and calibrate to the reading you wrote down.

That is the importance of the stability of olive oil.

Of course, if you run out of that original oil you are out of luck. Other oil will give a different (wrong) reading. (You could then buy some proper calibration oil... or follow RAB's iterative process.)

You could try golden syrup, but it is not stable (as it is hygroscopic). Different batches of golden syrup will differ, too. Better off on the breakfast cereals, but not as good as honey.

I would have to respectfully disagree. I believe we have different reasons for choosing a 'standard'.

You pointed out that "assuming it is correct now" the same 'standard' will give the same result in two years time… well what if your original sample wasn't correct? Sure it will read the same in two years, just the same amount of wrong…

My point is that all I wish to know is if the honey i'm bottling now is too watery, I don't care if the honey I bottle in a year's time has the same moisture reading or not. The important thing is whether that reading is correct or not.

If our reference sample is inaccurate, but stable (as I suggest a random sample of supermarket olive oil may be) we will keep on resetting our instrument to the the wrong value time after time.

What I want is not a stable solution, I want an easily available accurate solution I can check my refractometer against every season.

That's what I was asking for help with from the forum in terms of other users values for golden syrup.

Regards,

Thanks Enrico - No one can guarantee their calibration is any better than yours (or mine) but the more values are reported the more accurate the final average value will be. All those little calibration errors (be they plus or minus) will average out and we'll have a useful reading.

oliver90owner said:

but which one do you have to begin with?

ANY, it doesn't matter a .... hoot. As long as it is stable.

I don't think you really understand the reason for the standard oil.

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I would have to respectfully disagree.

I will just disagree. It is a load of codswollop. Up the creek without a paddle. A few others might come to mind.

What you are suggesting is rubbish all ways round.

By all means use your result for your sample, assuming the label on it is correct. But doing what you are proposing is just sheer crass stupidity on a scientific basis.

Try this. Your result on your syrup, 82%. Enrico' s result on his syrup, 80% average. = 81% if both your instruments were correct you would now be using the wrong value for your standard. Very simple -method is flawed.

Try this. This time both instruments are reading one percent too high and low respectively (due to wrong calibration) but this time you are both using the same syrup. Same result. The average of 81% will be spot on. Now try with both reading either one percent high or low. Do you get the same result? NO! Say the syrup was 81%, the pair of you could either get 80 or 82 percent readings and both would be wrong. Method flawed.

What if 90% of the results from the internet were wrong, for one reason or another, would you arrive at the correct result? Not very likely. Method flawed.

What you are suggesting is out and out rubbish.

You must adopt a standard value syrup and everyone must calibrate their instruments to that value. Full stop. A concensus value is just that, never the real truth.

Your failings (in your 'method') are obviously two-fold.

1). The assumption that all invert sugar samples have the same water content.

2). The assumption that all partaking contributors already have properly calibrated instruments.

Not very scientific that - making assumptions which you know are wrong.

There is a third. That of any results coming in from anyone who wishes to mess up your results.

Here is mine for instance. 70%. Obviously incorrect. But there may be an unknown number out there submitting a less obvious, but still wrong, result.

There is the one thing you have forgotten to check - corroborating evidence.

I advise you to drop your idea of any standardisation by the method you are proposing. The only likely outcome is that nearly everyone would be using an incorrectly calibrated instrument.
Anway, now that everyone else is fore-warned of the likely outcome of following your method, there should be few following down your sticky path.

I rest my case. By all means compare your results with any you might receive. But I can assure you the value on the container will be the correct one, within a tolerance, every time. What that might be is up toyou to guess. Plus or minus 0.5%, perhaps?

You don't, by any chance, use another screen name at times? Beenovice, by any chance?

RAB

I actually think you are onto something barley ward and I would love to see some more results. Come on folks let's give this a try!
E

enrico said:

I actually think you are onto something barley ward and I would love to see some more results. Come on folks let's give this a try!
E

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Possibly, but I'd be more dubious of golden syrup being uniform than the alternatives. Any water+sugar mix is going to change the longer it's open as the water content changes from exposure to the atmosphere. So you'd have to work with fresh packs, and as pointed out there are different brands and different formulations for the "squeezy" packs (more water = runnier?). Is there any reason to think the manufacturers won't change the process, or if the input (and therefore output) varies by source? The contents on the label are from standard tables, they are not calibrated measurements or even particularly accurate. And if you have honey in the house why would you want to keep opening tins of golden syrup?

For calibration you don't need to reproduce the sugar mix, you just need something with the same refractive index. If you really need to work to several decimal places, traceable calibration oil comes in a 5 vial pack (fresh via for each calibration run). It's over 100 quid a pack and has a 12 month expiry. Or there's a glass plate (also over 100 quid) used with a contact liquid (a bargain at 20 something). This is something of a presumption, but I'd expect medicinal liquid paraffin to be far more uniform than syrup, and probably more uniform than extra virgin olive oil given reports of "faking" by dilution with other oils. If you're buying something specially, for a couple of quid, that you don't mind having at the back of the cupboard for 11 months at a time that's probably the one to go for.

alanf said:

Possibly, but I'd be more dubious of golden syrup being uniform than the alternatives. Any water+sugar mix is going to change the longer it's open as the water content changes from exposure to the atmosphere. So you'd have to work with fresh packs, and as pointed out there are different brands and different formulations for the "squeezy" packs (more water = runnier?). Is there any reason to think the manufacturers won't change the process, or if the input (and therefore output) varies by source? The contents on the label are from standard tables, they are not calibrated measurements or even particularly accurate. And if you have honey in the house why would you want to keep opening tins of golden syrup?

For calibration you don't need to reproduce the sugar mix, you just need something with the same refractive index. If you really need to work to several decimal places, traceable calibration oil comes in a 5 vial pack (fresh via for each calibration run). It's over 100 quid a pack and has a 12 month expiry. Or there's a glass plate (also over 100 quid) used with a contact liquid (a bargain at 20 something). This is something of a presumption, but I'd expect medicinal liquid paraffin to be far more uniform than syrup, and probably more uniform than extra virgin olive oil given reports of "faking" by dilution with other oils. If you're buying something specially, for a couple of quid, that you don't mind having at the back of the cupboard for 11 months at a time that's probably the one to go for.

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I wasn't thinking of changing the way the world calibrates it's refractometers. I was just interested in the outcome!
Oh well...... Guess you folks would rather think things through and type loads rather than spend two seconds doing something totally useless for a bit of fun!

All of a sudden I like my 'shake test' that little bit more

Ely said:

All of a sudden I like my 'shake test' that little bit more

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