Refractometer Calibration

[psafloyd]

Given the refractometer scale is marked every 0.5 Brix I took my reference point for olive oil as being 71.5 Brix or or 26.5% water.

Virgin olive oil. I suppose that there will be some small deviation, but like electronics, 5% components are more than adequate for the job in almost all cases.

There is no nuclear reaction going to occur with a small error, just don't buy your virgin olive oil from a dodgy source for goodness sake.

The two links given by M100 surely spelled it out quite clearly. Did you read them?
The Wiki gave the refractive index of virgin and refined olive oil and the expected latitude; the other gave the conversion table from refractive index to Brix.

For the real newbees, please explain what's so difficult to digest about that?

If in real difficulty take up making mead.

My mate Hombre reckoned that you were fairly smart, but I think he might be wrong.

The difficulty is, WMSB, it has been suggested there is considerable variation in index across different oils. Without the knowledge (why I asked the question, and I doubt I am alone) to make a call on the importance of that variance, I asked for clarification.

Wikipedia is not the fount of all knowledge and without the benefit of experience, it is difficult to know how accurate it might be.

Now I know any variance is unlikely to cause a significant error, thanks to your most gracious contribution, I feel far more confident in approaching the matter. My apologies for seeking a definitive answer as opposed to staggering around blindly in ignorance.

My thanks to Hombre for his confidence in my acuity, but if you remain unsure, perhaps you might ask a question of this fine forum.

However, don't go for a definitive response, or you might leave yourself open to criticism, which of course would be unwarranted in your case.

 

[WaxManSmokerBoy]

Hombre says that I should wind my neck in . . . ha ha; and thinks that it was a bit of a B class question in search of an A class answer.

Back to the rioja then. Hombre

 

[psafloyd]

I'm sure he is right. Certainly about my question. But I did get an answer, so thanks all.

And there's nothing like Rioja for inspiration.

 

[Black Comb]

Well PSA you are quite smart as you weren't sure so you asked.
How many times do you hear on beginners courses that "there are no stupid questions, if you don't know ask". Also repeated on here.

 

[mattiker]

I have to say that the idea of using a random olive oil to calibrate a scientific instrument seems pretty flawed. I doubt very much that you can trust wikipedia to be 100% correct and account for differing environmental factors. So the moisture content of the olive you choose could be very different to what you expect. I would expect there to be too much variance to be accurate for purpose of calibration. Has anyone tried measuring a few different olive oils (i.e different brands) to see if this is correct?

Regards,

Matt

 

[Hivemaker.]

Has anyone tried measuring a few different olive oils (i.e different brands) to see if this is correct?

Yes, as i have mentioned before,and they were all different.

 

[drstitson]

the random oil i chose read 71 on brix scale so spot on.

 

[Hombre]

It obviously wasn't random Dr S, because you "selected" it. Nothing random about that surely.

Very uncomplicated though, thank goodness.

 

[Tom Bick]

I don’t know but if you want to calibrate the refractometer then I assume you think it may be inaccurate in some way?

So in a rather simplistic way why don’t you test it on capped honey that to me would give me confidence.

 

[psafloyd]

Tom,

That is an excellent idea and an elegant solution to the conundrum. After all, if the bees have got it right, it is likely to be <20% water.

I don’t know but if you want to calibrate the refractometer then I assume you think it may be inaccurate in some way?

So in a rather simplistic way why don’t you test it on capped honey that to me would give me confidence.

 

[Hombre]

Brix - the variation in the spread of both honey and olive oil

An admirable simplicity to the technique as well Tom.

I love a bit of irony or course, so have to suggest that the spread of the Brix readings for honey that is capped is probably about the same as for olive oils, (71 to 72.6) or a variation of 1.6 Brix.

The irony is that it is 27 days since the first post and 27 posts since post #3 where Hivemaker suggested using olive oil, with possibly the same or lesser Brix spread than honey (pun not intended - actually).



Begins with L, ends with Y, a symptom of our times when it comes to independent research. L * * Y JOURNALIST. LoL

 

[Hivemaker.]

And the different moisture % even in capped honey is not so reliable,some ordinary honey could be 15%, and heather as high as 21%.

 

[newportbuzz]

can i sugest that you can use a sugar water solution.
just be carefull with your measuring. i test all my 2:1 to make sure i havnt made a boo boo.

anyway 1:1 syrup is 50brix simples or 50% sugar 50%water. the bonus is after your done you can feed it to the bees.

 

[drstitson]

Surely most of our dedicated refractometers don't go down to 50%?

How can you make a boo boo when making syrup?

1. count 2kg bags.
2. add to same number of litres of boiling water
3. mix (with heat as necessary)

 

[newportbuzz]

ive been known to forget to count. that and i do 25kg at a time and my kettle does 1.7ltr at a time.

my one goes to 58 brix which would be attainable acuratly by mixing sugar and water. anything up to about 69brix should work before it starts droping the sugar back out.

 

[drstitson]

"ive been known to forget to count. that and i do 25kg at a time and my kettle does 1.7ltr at a time."

I do 20kg at a time in my Lidl boiler. easy to fill to a required level with water.

 

[oliver90owner]

ive been known to forget to count. that and i do 25kg at a time and my kettle does 1.7ltr at a time.

KISS principle: note the level with the dry sugar; add hot water to that level. Job done. Don't need to count; close enough; no mathematics, just plain old fashioned, reliable method for any weight of typical granulated sugar, or shape of vessel (some erroneously think it has to be a flat bottomed pan!?!). Won't work for a couple kilograms of sugar in a burco boiler, of course, but if counting for that is muffed there isn't much hope for the individual, is there?

I have never ever considered checking the ratio for made-up sugar syrup. It would ferment whatever the water content (without thymol or other appropriate additive) if left around. Better things to do. Much more important when making fondant, of course.

RAB

 

[Magic munchkin]

Can anyone confirm if using olive oil is a good enouhg way to calibrate?
Spoke to Gary @ gainexpress and he said i have to use dioptric oil.
I calibrated it using extra virgin olive oil and the tub of honey i was unsure about read 19 and the honey i was sure about was 17.

 

[oliver90owner]

So what , if it is out by 2%? 20% reading will have the same error; 18% honey will give the same error when reading it with the refractometer (ie 20%).

Who else will care? Nobody. Your 'calibration' oil will allow you to check that the 2% reading error is still the same. All you need to remember is that there is a 2% difference btween what you observe and the absolute truth.

Just like a car speedo- what it reads and what the real speed is could be up to a 10% error. No excuse for breaking the speed limit, but equally nothing youcan do simply/cheaply to eradicate the error. You just live with it.

 

[Hivemaker.]

If you tested some honey you were sure about the moisture content,ie 17%,and the refractometer read 17%,then its accurate.