Refracto computes the following values whenever you change one of its input values:
The resulting Original Gravity (OG).
The estimated alcohol concentration as percent by volume (ABV).
The Final Gravity (FG), displayed on the top as apparent gravity and as actual gravity on the bottom. The apparent gravity corresponds to the value you would measure with a hydrometer. The actual gravity is a corrected value that compensates the effects of alcohol influencing a hydrometer.
The amount of sugars consumed by the yeast so far, displayed as apparent attenuation on the top and as real attenuation below. In practice only the apparent attenuation is relevant.
The computed values can be customized. This is described in the next section.
The settings tab allows you to configure Refracto to your needs. The available options are:
Use this switch to select between a splendid bright and a stylish dark interface theme. The Screenshots section below shows both variants in full detail.
The gravity unit to display computed values can be set to Plato (°P) or Specific Gravity (SG). Plato is traditionally used in parts of Europe, while the modern Specific Gravity is widespread in the US and UK.
The Wort Correction Factor is used to convert your initial Brix reading of the unfermented wort into the Original Gravity. The brewing literature mentions typical values for this factor in the range from 1/1.02 to 1/1.06. By default Refracto uses a value of 1/1.03. If in doubt, set the Wort Correction Factor to 1/1.03 or 1/1.04 which are the most commonly used values.