I recently purchased a Handheld unit with a Brix scale of 58-90% and a water scale of 12-27%. This QUESTION is for those Beeks who have know-how. I am having difficulty in understanding the calibration instructions ( I am a DUMMY ). Using distilled water to calibrate, 2 drops on the prism and adjust the screw to move the light/dark boundary to coincide with the NULL line. ON the 12-27% scale, what is the NULL LINE ?
This is my first instrument, so any input from you experts will help. Thank You in advance.
If you refact pure water the reading should be Zero. Pure water is used as a calibrator for refractometers. The scale will show the percentage of sugar within the liguid being tested. A valencia orange will refact at anywhere from 8 to 23 depending on ripeness location on the tree and even to the time of day it was harvested.
If you want a crash course on using a refactometer visit your local Orange Julius. They use them daily and can demonstrate it's use (using fresh squeezed orange juice). I know--I use to manage one after I retired from Police Work and before my injuries froced me out of the labor force altogether.
What is a good quality Handheld Refractometer to buy? I see some on ebay that look like they don't go any finer than whole numbers percentage and are only accurate up to +-1%. I haven't truly shopped around but I need one soon and so I would greatly appreciate any help with makes and models.
A good refactometer will go for around $80 or more. A +/- 1% is acceptable and pretty much the standard. I recommend the type that look a little like a telescope on one end and a beveled lens on the other. The beveled end has a flap that holds the fluid in place as you look through the eye piece and the displace will be perpendicular as a gray scale.
Wash the beveled end before and after each use. Even between individual tests--If you want to do more than one just to be sure--wash the lens
All that blather and I forgot to answer your question as to what is the null line. When you've put a drop of water on the lens adjust the eye piece until there is no gray or white line showing. The meter is now set at null or zero. Some meter have a fine black line etched in them that can be seen when peering through the eye piece--this is also the null line and the refractometer should be set so that only the line is visible when using water--it is not necessary to use distilled water. I would not use well water due to ppossible non-essential elements clouding the water and giving false reading. Any water from a municiple water supply should be fine.
> ON the 12-27% scale, what is the NULL LINE ?
I think you have instructions for another refractometer,
rather than the one you have in hand.
[list=a]
- Distilled water is going to have 0% sugars.
- Your refractometer reads a minimum of 12% sugars.
[/list:o]
Therefore, you don't have an actual "null line" on that
scale - you may have a longer line on the center scale,
between 19.2% and 20.2% moisture (just below 79%
sugars) like this:
(http://bee-quick.com/refractometer.jpg)
But this line requires "calibration fluid", something that
is often forgotten when refractometers are sold, something
that should be demanded from the vendor.
Easier to calibrate your refractometer against a honey judge
or another beekeeper's refractometer.
Thanks for the help everyone. :D