The refractometer is a neat little tool for measuring the specific gravity and brix % of wort. Use the refractometer during your brew to monitor the efficiency of your mash, sparge and boil. Easy to use and clean and requires only a few drops of wort to take a reading. Drop the wort on to the lens using the pipette provided and close the daylight plate. Hold the refractometer up to the light and view the reading through the eyepiece. Take a reading from where the light changes from blue to white.