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Refractometer use

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I know this has been covered at length before, but I'm not sure the correct informatiion is out there yet and I remain a bit confused.

It has been suggested that you can calibrate refractometers using, for example, olive oil, of known water content, but I don't think it is that simple. If the basic refractive index of the calibrating fluid (in this case, the oil) is significantly different from what you want to test...honey in our case, the result might not be correct. That is why seemingly identical refractometers for checking the Brix of grapes for example, are not suitable for use with honey. Ideally you should use commercially available calibrating fluid, but it is very expensive, perhaps for good reason - the makers say you can't just use any liquid or syrup with a known water content for calibration purposes. Of course, how accurate you have to or want to be is another matter...near enough might be good enough for most purposes. And surely you could get a 'near enough' result using a honey-like fluid. For example, Chelsea Maple syrup which you can buy in the supermarket is very like honey in texture and sugar content; - and the factory claims it has a water content of 24%, plus or minus 0.5% guaranteed. Yet when I calibrated using it, I got a surprisngly high result for my honey. Oh dear...what do members think?

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RFs used for Brix (and honey) assume we are dealing with sucrose and water only, at 20C. Using other sugars, or a mixture, or water/alcohol (as in beer) will give you inaccurate results because the refractive indexes are all different, and if you have temperature compensation it won't work. Mine, like many is calibrated with an oil, and the makers general choose things (like oil) which are in the right range, are stable, easy to clean, and non-toxic. The oil used is specified assuming I'm measuring sucrose. Thrifty types use a (pure) olive oil, look up the refractive index, and hope for the best. We are actually measuring, fructose, glucose, sucrose, and a few other sugars, so if you're looking for four decimal places it'd be wrong. But if I check mine against a saturated sugar solution it tells me it's 66.5-67%, and I know that the solubility of sucrose is 2000g/L (25C). (It tells me on Wikipedia!)

To me, the obvious thing, if near enough is good enough, is to calibrate using a saturated sugar solution. Super-saturated is not necessary, just saturated.

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Ok great all calibrated so now how are going to collect that sample, which frame , from where ?????

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how are going to collect that sample, which frame , from where ?????

I don't sample from the frame (but I could), I sample extracted honey. What are you trying to find out?

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Doing lots of small extractions for artisan honeys wondering should we sample from frames prior to extracting, if so how does one establish the mean. Or is that a waste of time just take capped honey and extract then measure result?? If that is then too moist do we run a fan over the buckets till it drops?

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Correct me if I am wrong but I don't think the water content of the honey in the cell will change after it has been capped. Water content changes when the capped honey is uncapped and exposed to air, the water content will only go up after extracting unless you "dry" it using a fan. Assuming you like to know the water content of the honey when you bottle it, doesn't it make more sense to meassure it after extracting?

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wondering should we sample from frames prior to extracting

I must be a bit thick today, why are you wondering about this? I'll say it again, what are you trying to find out?

 

If that is then too moist do we run a fan over the buckets till it drops?

You need to be a bit more sophisticated and set up a suitable dehumidifier, but kind of, yes. It is possible to have the opposite problem - it is too 'dry'. Sell it like that and you're giving money away, so you might actually want to put water back into it.

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Dave i have read several books and articles that talk about checking how dry it is prior to extracting and loads about stacking supers on fans to dry before extracting. I think mostly in reference to the percentage of uncapped per extraction. I shall just ignore all this and extract and sample after?? I have only ever extracted small quantities of capped honey but expect to extract over a tonne this season and as it will be sold i am trying to assess how to ensure the product is right.

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I see @Gavin Smith. I don't know of anyone sampling the honey in supers here, but it can be done. Unlike in the hobby world there is often a mix of honey - mostly sealed but some unsealed or from different places, and that is tested to see the extracted honey is within spec, and 'fixed' if it isn't by blending. When supers are stored in a hot room prior to extraction sometimes the RH is controlled (to less than 60%) as, at this point, unsealed honey neither gains nor looses moisture if it's at the right water content. Clearly you can also control the RH (by blowing in warm dry air for example) or blend it if you want it to be different. It is easier to lower the water content when the honey is in supers that when it is extracted, but raising the water content is pretty easy in extracted honey. I know several beekeepers on this Forum who do alter the water content of the extracted honey and have built special equipment to do it. I also know of plants in Canada who control it in the supers, so I guess it's a choice you make. Maybe in NZ it can still take up water during processing, in Canada it doesn't.

Either way, you are going to need a refractometer and a hygrometer (or wet-bulb) :)

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Doing lots of small extractions for artisan honeys wondering should we sample from frames prior to extracting, if so how does one establish the mean. Or is that a waste of time just take capped honey and extract then measure result?? If that is then too moist do we run a fan over the buckets till it drops?

Notwithstanding @Dave Black 's point about dry honey I cannot see any reason to sample capped honey on the frame. It won't be capped if it's not at the 17-18% range.

 

In the field I have only ever sampled uncapped honey (randomly?!) when >50 % by the eye-o-meter is uncapped to see that the moisture level is around 18% - if it is then I extract the frame. I RF sample once the uncapped frame passes the shake test - no nectar flies out!

 

I also sample the 10litre pail once full of uncapped extracted honey to see it's <+18% moisture across the homogenous sample. It's then passed to filtering and jar filling! To avoid issues I try to combine uncapped with capped frames at extraction so try to average any higher moisture honey down.

 

I have misplaced the calibration oil (Dioptic oil) I got with my refractometer so use extra virgin olive oil to calibrate it. Legit olive oil should be 71-72Bx so I calibrate at 71.5Bx. That is well within the range of honey testing.

 

I bought my refractometer from eBay in Hong Kong - cheap and effective. I am looking for results =<18% so don't need 4 decimal places hence I can use olive oil as the calibration test. One could save their costly dioptic oil by first using it and calibrating the RF then testing a legit olive oil sample - if the olive oil is 71-72Bx then save that actual oil in a bottle and use it as a cheaper source for general calibration testing.

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Thanks guys, with you on all that. Also use extra virgin to calibrate, seems to work well. I have read that shaking an uncapped frame will shake off the wet stuff. The amount of uncapped or percentage wise i was thinking of is probably negligable. So i will shake and extract the test before bottling. Thanks again.

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Thanks guys, with you on all that. Also use extra virgin to calibrate, seems to work well. I have read that shaking an uncapped frame will shake off the wet stuff. The amount of uncapped or percentage wise i was thinking of is probably negligable. So i will shake and extract the test before bottling. Thanks again.

If you see nectar fly out when you shake then it probably needs to stay on the hive.

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well..that's all great guys. Thanks for the comments. I take the point about why we should want to determine the water content of honey...but in my case, I had so much honey being put into a new super in the middle of winter that I decided to extract some of this...and there was a suggestion that this 'winter honey' would be likely to have a higher water content, and therefore be prone to fermenting, due to the cold conditions etc. So I bought the refractometer (under $30 from AliExpress...delivered!) to check this. Still not sure what the exact water content was, but it was the same as my normal summer honey, which was the point of the exercise!

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Just by the by, what sort of honey do you think it is ?

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well..that's all great guys. Thanks for the comments. I take the point about why we should want to determine the water content of honey...but in my case, I had so much honey being put into a new super in the middle of winter that I decided to extract some of this...and there was a suggestion that this 'winter honey' would be likely to have a higher water content, and therefore be prone to fermenting, due to the cold conditions etc. So I bought the refractometer (under $30 from AliExpress...delivered!) to check this. Still not sure what the exact water content was, but it was the same as my normal summer honey, which was the point of the exercise!

I'm not surprised. The bees reduce the water content to a level that enables long term storage without fermenting. Winter summer whatever - the bees will stick to their program and cap at the right point.

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As a matter of interest, does the capped honey moisture content vary much from the 17-18% range. If not, why not just uncap a few cells from the frame and use that as your calibration fluid?

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Good idea to check water content of both capped, and uncapped honey on the same frame...would be interesting to see if there is a difference!

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As a matter of interest, does the capped honey moisture content vary much from the 17-18% range. If not, why not just uncap a few cells from the frame and use that as your calibration fluid?

I think the answer is you know where you are with a well known fluid. But as a quick and dirty on the fly method your idea works.

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Just by the by, what sort of honey do you think it is ?

We think it is five finger honey...there is heaps of this tree around our place and we know it producs nectar in winter. The tuis love it..and we heard/saw lots of bees on it in June and july. Tastes great too!

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