A refractometer is a device utilized by many industries but has a very useful place within the homebrew community. It can be used to measure the Brix of a very small quantity of wort which can be converted to a Specific Gravity reading. Many refractometers already include a Specific Gravity scale on them which is quite helpful.
The advantage of using a refractometer is that it uses a very minute amount of liquid in comparison to using a hydrometer. The wort placed on the refractometer cools very quickly and therefore temperature is not an issue and conversion calculations don’t need to be utilized.
The complication with using a refractometer, however, lies in the fact that once alcohol is introduced into the solution being measured, complex calculations must be utilized in order to arrive at correct Specific Gravity measurements. That is where the above calculator comes into play. Enjoy!