Refractometers are used to measure the quantity of sugar dissolved in water.
Compared to hydrometers, they have the advantage that only a few drops of liquid and needed and that the measurement doesn’t need to be corrected for temperature.
However, the measurement is affected by alcohol, and the Final Gravity reading needs to be corrected using the calculator below.
To achieve the best possible results, you should use the average of several readings.
*Ideally, you should also apply the wort correction factor that can be calculated using this worksheet from Brewer’s friend. If you haven’t calculated your refractometer’s wort correction factor yet, leave this value as 1.
More information about how to use a refractometer in this post >>