1. Prism

2. Cover Plate

3. Setting Screw

4. Mirror Tube

5. Eye (adjustment ring of dioptre)  




Putting it simply, a refractometer will allow you to take an accurate gravity reading of your wort. It does this with just a few drops of the wort which means less waste.

Before using your refractometer be sure to calibrate it (see below).

After lifting the clear plate which covers the lens, add a couple of drops of your wort to the lens. Gently press the cover plate back down on the lens which should spread the drops of wort uniformly across it.

Then point your refractometer toward a light source and look through the eye piece to get your reading.   

Calibrating your refractometer

Aim the front end of the refractometer in the direction of bright light and set the adjusting ring of dioptre until the scale can be seen clearly. Open the cover plate, put one or two drops of distilled water on the prism. Close the cover plate and press it lightly. Then adjust the setting screw to make the light and dark limit coincide with the ZERO line. If the instrument is ATC (with Automatic Temperature Compensation system), the room temperature must be 20°C whenever the instrument is recalibrated. Once calibrated, shifts in ambient temperature with an acceptable range (between 10°C - 30°C) should not affect accuracy.


After taking the measurement, clean the remaining liquid on the surface of the prism and cover the plate with a damp gauze. After drying, store the instrument carefully.

Temperature compensation

The reference temperature is 20°C (68°F). Refractometers with “ATC” have an automatic temperature compensation.

If you need to make temperature corrections this can be done using the table below.


Avoid washing this instrument in water. Handle gently and avoid touching the optical surfaces. The refractometer must be stored in a dry, clean and non-corrosive environment. Avoid strong shocks.


Suction tube / Screwdriver / Case / Cleaning Cloth


Corrections for temperature applicable to density hydrometers standardized at 20°C (68°F) or 15°C (59°F):

These corrections when applied to the hydrometer reading at t°C give the density of the liquid in kg/m³ or g/ml at t°C.