Refractometer Calibration using solution

[kombujo]

Hi All,

My refractometer started giving inaccurate results. I am testing a sweet tea solution. Adding 42g sugar per litre of tea and readings are coming in at BRIX 3.5. Usually they would be bang on at BRIX 4.2

I checked with RO water and reading is at 0. I bought some calibration solution and it read BRIX 4.4, so I adjusted the refractometer according to the instructions to read BRIX 3.5. Now when testing the sweet solution it is way off.

Am I misunderstanding the usefulness of calibration solution? Could my refractometer just be in need of replacing?

Cheers
Jo

 

[beeralchemist_th]

Have you try reading an unsweetened tea? First, the refractometer is not detecting only amount of sugar in solution, instead a lot of substance can contribute to the reading, including alcohol and salt. The tea itself might contain something that would give a reading that not a 0 on refractometer. Once it mixed with the sugar, it gave out different number rather than the just pure sugar solution.