Hydrometer Temperation Correction Tool

A hydrometer is an essential homebrewing tool that allows you to determine the amount of alcohol in a liquid. By taking density (gravity) measurements before (OG) and after (FG) fermentation, you can use the measured readings (along with the temperature) to determine the ABV (alcohol by volume).

How to Read a Hydrometer

Reading a hydrometer is just a matter of eyeballing the level of the liquid against the measurement lines. There are, however, two things to keep in mind. First is the temperature of the liquid being measured. The temperature of the wort can alter the gravity, and therefore change the reading. Second is taking into account the curve of the fluid on top, also known as the meniscus. As shown in the picture, you will want to ensure your reading is taken at the base of the curve.

Finally, a note on hydrometer calibration. All hydrometers are "calibrated" to be accurate at a certain temperature. Older units were typically set to 59-60 °F, while newer models are generally calibrated to 70 °F. The instructions that came with your hydrometer will specify your calibration. If you are unsure, you can always determine your hydrometer's calibration by taking a reading of distilled water, which should measure at 1.000. If you determine the temperature at which your unit reads 1.000, you can use that as your 'calibration' temperature in this calculator.