Refractometer

When brewing you would like to know the gravity of your wort. Based on the original gravity (OG) and measuring the final gravity (FG) using a refractometer you can calculate the alcohol percentage of your beer. You require this calculator because the alcohol in the beer does not show the correct gravity.

You can take your fist sample from the bottom filter when you remove the keg after brewing (OG). Take the last sample from your trub container after the second fermentation phase (FG). Use these numbers to calculate the alcohol percentage of your beer.

A word of warning: not all refractometers are the same, and some even have a wrong SG scale. If you want to test your meter you can do so by weighing 20 grams of sucrose (99% pure) and top up / dissolve with water till it turns 100 grams ( do not simply add 80 ml / grams of water ). The refractometer should read 20 Brix (20 Plato) or 1083 SG.

If you have a wrong SG scale you can simply read the Brix % and use one of the online conversion tools mentioned above (or Google for a table to print out).