A Refractometer is an excellent, accurate tool used to measure gravity (in Brix/Plato) of unfermented wort or must. Allows the brewer to monitor gravity while mashing, or during a boil.  Since only a small sample (drop or two) is used you do not have to spend time cooling a large sample to use a traditional hydrometer.  This unit has Automatic Temperature Correction (ATC) so you don't have to adjust your readings based on temperature.  A simple chart gives Specific Gravity based on the Brix or Plato reading of your sample. Unlike a hydrometer, only a few drops are required for a sample. To use, apply 2-3 drops to the prism face, close cover, and look through the eyepiece while aiming your refractometer at a light source.

• Range of 0-30 Brix/Plato (1.000-1.130 SG)
• Instant reading
• Automatic Temperature Correction (ATC)
• Use a sample of just a drop or two 
• Easily monitor SG of mash runnings
• Monitor concentration of boiling wort