Hydrometer temperature correction
A hydrometer is calibrated at one temperature, usually 60 °F or 68 °F. A warmer sample reads low. Enter your reading and temperatures to get the true gravity.
Corrected gravity
Corrected gravity—
Save it in a recipeThe calibration temperature is printed on the hydrometer or its paper scale.
Why temperature matters
Warm wort is less dense, so the hydrometer sinks a little deeper and reads low. The correction uses the density of water as a function of temperature: corrected gravity = reading × ρ(calibration) / ρ(sample). Above about 100 °F the correction becomes less reliable: cool the sample first.
Questions
Can I measure hot wort?
Better not: cool a sample to near room temperature. The correction stays accurate within a few tens of degrees of the calibration temperature.
My hydrometer reads 1.002 in water. What now?
Your hydrometer is off by 0.002: subtract that offset from every reading, in addition to the temperature correction.
Do digital hydrometers need this?
iSpindel and Tilt report temperature-compensated values once calibrated. Mashwerk records them directly.
Track every batch, not just one number
Mashwerk computes this for every recipe and brew, from your own equipment and readings. Free plan, no credit card.
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