calibrating refractometers

[drstitson]

what do people use - just distilled water and adjust to 0?

 

[oliver90owner]

I would think most who wish to calibrate, use an oil of known Refractive Index (RI).

As honey is mixture of sugars, I would not expect the result to be an absolutely accurate to the nth degree.

I have never checked mine - I know that reasonable figures are indicated for capped honey and assess from there. Rarely use it anyway, but it is there for those odd occasions.

Regards, RAB

 

[drstitson]

thanks Rab - it's for a colleague - have managed to find a bottle of immersion oil (Ne 1.518) at work (most of us now have 63x dry high power lens rather than 100x OE so oil not used often).

 

[oliver90owner]

I think olive oil would do.

Regards, RAB

 

[hughjamton]

Tropical marine fish shops will either have a pure water, purer than distilled. that you can purchase, or if it's a "profesional" shop they will do it for you free, don't tell them it's for honey
It has to be very accurate for fish and corals, far more accurate than is required for honey.

 

[drstitson]

"pure water, purer than distilled"

no worries - we have proper "pure" water for the lab!!!!

or are we now getting into the realms of homeopathy whereby our refractometers must be calibrated using D60 Honey?

 

[oliver90owner]

hughjamton,

Please tell us more. I had no perception of a refractometer being used for a fish tank!

I could understand, perhaps a hydrometer, or a pH meter, but a refactometer would seem to serve no purpose with a fish tank.

Regards, RAB

 

[drstitson]

rab - take a look on google/fleabay - whole range of refractometers available - some brix, some for salinity etc.

http://reefkeeping.com/issues/2006-12/rhf/index.php

at the end of the day all they are doing is measuring RI - perhaps the name of the device should be clearer! - if you have an appropriate chart you can use it for anything. The only difference in the various models is the convenience of having your own particular need (eg brix scale) etched onto the device rather than having to measure the RI and looking up the result.

 

[Deeperdiverdude]

hughjamton,

Please tell us more. I had no perception of a refractometer being used for a fish tank!

I could understand, perhaps a hydrometer, or a pH meter, but a refactometer would seem to serve no purpose with a fish tank.

Regards, RAB

Hi
One of my other hobbies is keeping marine fish and I use a refractomter to check the salinity of the water that they live in. I suspect that it might not be suitable for honey as I would think it was only calibrated for water/salt.

I would be interested to know if it can be used for honey?

Btw - it does need to be regularly checked using pure RO (reverse osmosis) water as it can vary.

DDD

 

[oliver90owner]

drstitson,

Wow, thanks for that link. I would still be using a hydrometer! Learn something new every day. I have never kept more than one, or a few, goldfish, so know nowt about it.

We always checked aromatic oils for RI as a QC check on arrival, but that was using Lab apparatus (the 'hand-helds' didn't have anywhere near the resolution we needed for some oils).

Regards, RAB

 

[drstitson]

"I would still be using a hydrometer! Learn something new every day. I have never kept more than one, or a few, goldfish, so know nowt about it."

rab - like you no experience of these specific uses.

however i'd imagine that using a hydrometer by the time i'd got the SG down in the "traditonal" way the fish would have died of alcohol poisoning!

 

[oliver90owner]

the fish would have died of alcohol poisoning!

Yes, maybe!

A 'traditional' set of hydrometers to me may have been up to about ten in a set! The alcoholic range is a bit limited!

Regards, RAB

 

[drstitson]

"A 'traditional' set of hydrometers to me may have been up to about ten in a set! The alcoholic range is a bit limited!"

that sounds like overkill to me - i'll stick to my old boots hydrometer and Tala jam/toffee thermometer.

 

[susbees]

So have we agreed in simple terms what is suitable for calibrating refractometers for honey? Is olive oil a goer?

Got the machine but not used it yet...

 

[user 6228]

marine fish - that new to me- but so far i've only used a refractometer at home to check the "soluble oil" content of cutting fluid in the workshop. A long time as a student ago I did use it to check sugar concentration, but wasnt one of the hand held things.

 

[Hivemaker.]

I think olive oil would do.

Regards, RAB

Tested three different brands of olive oil in the past,new bottles, and each one different RI, so now need to test with a fluid/oil that is accurate, to find out which one of the olive oils is the correct one to use for setting the refractometer......lol.

 

[susbees]

Tested three different brands of olive oil in the past,new bottles, and each one different RI, so now need to test with a fluid/oil that is accurate, to find out which one of the olive oils is the correct one to use for setting the refractometer......lol.

Ah...well, logical really.

 

[Moggs]

I use two refractometers - one for a marine fish tank to check salinity at 1.023 and the other for honey at <20% moisture. Couldn't risk salty honey could I? And the ranges are so far apart as to be unworkable, one to the other. So, easy enough to calibrate old salty with deionised water but what about the honey - is there a consensus on oil and reference values?

 

[MJBee]

Typical - I spent an hour reading all the search results for "refractometer calibration" only to fine this thread was 4th on the list.

I used extra virgin olive oil to calibrate my Hong Kong cheapy I set it at 71.5 Brix which gives 26.5% water. When tried with capped honey it gave a reading of 18% water so it would appear to be in the parish.

 

[Nic Rhodes]

Use an imersion oil from microscopy, they will be of a known RI, where as olive oil is variable (as are others). Imersion oil is cheap and many of the beekeepers may have a bottle anyway for microscope use as most scopes come with an 100x oil even if we rarely use them. It will get you in the right ball park for calibration.