Calibration of the refractometer
There is a simple and fairly reliable method for adjusting (calibrating) the refractometer: using extra virgin olive oil.
According to a test conducted by Dr. Werner von der Ohe from the Bee Institute in Celle, calibration of the refractometer with extra virgin olive oil at a temperature of 20 ºC is possible. Tests using three different extra virgin olive oils showed a maximum deviation of 0.08 % (see the article published below in ADIZ – die biene – Imkerfreund).
The refractometer is considered a precision measuring instrument. In theory, an annual verification of your refractometer should therefore be carried out. Some devices are sold with a calibration kit consisting of reference solutions or glass prisms; however, nowadays refractometers are often sold on their own.
Ideally, a high-quality honey has a water content not exceeding 17.5 %. This allows the beekeeper to sell a high-quality honey that does not ferment at the customer’s home.
How can the refractometer be calibrated?
- Place two drops of extra virgin olive oil at 20 ºC on the prism
- Turn the adjustment screw until the scale shows a water content of 27 % and 71 Brix
See also the article: How to control the water content of honey?