# How to use a refractometer??



## AstroBee (Jan 3, 2003)

I recently bought an inexpensive refractometer off ebay. Ive never used one or seen one used and the instructions that come with this unit is poorly written and has left me a bit confused. I searched the web but have found conflicting information. The unit I purchased is the RHB-90 ATC and comes with calibration fluid, a specimen dropper, a calibration screwdriver, and a small rectangular piece of glass. Its not clear from the instructions what the purpose of this small glass. Further, all web-based instructions (not specific to my unit) say to place specimen on the main prism assembly and then close the daylight plate (the plastic hinged cover over the main prism). However, the instructions that came with my unit say to leave this cover open. If the daylight plate were left open it would seem difficult to control the thickness of the specimen and would affect results. 

Is this small rectangular piece of glass used in place of the daylight plate? If so, that seems to be a poor design as the unit is only good if you never lose this tiny piece of glass. 

Any pointers gratefully accepted.


----------



## BubbaBob (Jan 18, 2005)

The "tiny piece of glass" is a calibration stone, a "known" result for calibration purposes ... don't lose it.

When calibrating, put the polished side of the stone down on the (approximate) center of the prism and look thru the eyepiece toward a bright light. The line should be at "x" % moisture (I don't remember the % but it should be in the instructions.

Once calibrated, to test honey, smear a bit on the prism, close the cover, and again look at a bright light through the eyepiece. The % the blue line is at is your honey's moisture content.

BubbaBob


----------



## Guest (Jul 6, 2005)

Further to this original inquiry, for the RHB-90 ATC is the little calibration stone used with the or without the calibration fluid? According to the directions, I think you are supposed to set the refractometer so that the boundary between the blue and the white is at Brix 78.78

Also, how are you supposed to clean the unit after you have smeared it with honey?

Assistance will be most greatfully appreciated.


----------



## BubbaBob (Jan 18, 2005)

Calibrate with the fluid, read honey without.

The drop of honey cleans up easily with water.

BubbaBob


----------



## AstroBee (Jan 3, 2003)

BubbaBob,

Thanks for your input. I now feel pretty comfortable with my refractometer. I do believe that its a little strange that you calibrate with the glass calibration prism and then do field tests with the plastic daylight plate. Seems to me that the two would have different refractive indices, which would lead to different readings. I guess if I ever have 18+ % honey that I don't want to dry, I do the more precise test using the glass calibration prism.


----------



## NW IN Beekeeper (Jun 29, 2005)

Degrees Brix (symbol °Bx) is a measurement of the mass ratio of honey to water in a total liquid solution.

A 85 °Bx solution has 85 grams of honey per 100 grams of total liquid soultion. Or, to put it another way, there are 85 (parts) grams of honey and 15 (parts)grams of water in the 100 (parts) grams of total liquid solution. 
Since Brix is based on 100 parts (percents), we can easily figure the moisture percentage by subtracts whatever index we read from 100. 

Therefore, 
88 Brix = 12% Moisture
85 Brix = 15% Moisture
80 Brix = 20% Moisture

I hope this clarifies how brix = percentage. 

Jeff

[ December 23, 2005, 08:57 AM: Message edited by: NW IN Beekeeper ]


----------



## john corne (Sep 20, 2006)

I have just bought one of these refractometers. The calibration instructions haven't improved since Astrobee bought theirs!

The instructions say to adjust the calibration screw untill the blue/white boundry reaches 0. Wel, of the three scales, none go that low! What value SHOULD the calibration fluid be adjusted to?

There is nothing to indicate what the liquid is, either!

Jc


----------



## Jim Fischer (Jan 5, 2001)

Ah, methinks you have something that looks like this
when you peer into the eyepiece.

See the calibration line?
You are looking for something like that.

The instructions for these gizmos were clearly
written by a person in Taiwan who spoke only 
Korean, translated to Russian by an intern who 
actually spoke only Serbian, then translated 
to English by a Rumanian who got a "C" in English 
and a "B" in Russian.

The worst example of poor translation I've
ever seen was evinced by a store window in
Tokyo, photographed by one of my employees
before Christmas. They had Santa in the
window... _nailed to a crucifix_.


----------



## john corne (Sep 20, 2006)

Thank you Jim,

That little line is SOOO obvious  

Thank goodness it wasnt anything serious, or maybe WWIII could have broken out!

Jc


----------



## magnet-man (Jul 10, 2004)

One would think the bee supply houses would include clear instructions as part of their customer service.


----------

