GIFSQ Tools · Module 07 — Dairy, Milk, Cheese & Fermented Products · Tool 125 of 500
Correct a Quevenne lactometer reading to the standard 15.6 °C (60 °F) and get the specific gravity of the milk.
Try sample values — fills the form with the worked example below.
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Corrected reading (degrees)
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Specific gravity
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Correction applied (degrees)
Equation: Corrected reading = observed reading + 0.18 × (milk temperature in °C − 15.6). Specific gravity = 1 + corrected reading ÷ 1000.
Method: Quevenne lactometer correction to the 15.6 °C (60 °F) standard: 0.18 lactometer degrees per °C, the metric form of the standard 0.1 degree per °F rule (AOAC 925.22, specific gravity of milk). Specific gravity follows from the corrected reading.
Assumptions: the lactometer is calibrated at 15.6 °C; the 0.18-per-°C factor is the accepted linear approximation over the usual milk range.
Limitations: the correction is approximate outside 10–30 °C; a lactometer cannot separate the effects of fat, solids and added water — confirm with total solids and fat tests.
Rounding: corrected reading and correction to 2 decimal places; specific gravity to 4 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Method: Quevenne lactometer correction to the 15.6 °C (60 °F) standard: 0.18 lactometer degrees per °C, the metric form of the standard 0.1 degree per °F rule (AOAC 925.22, specific gravity of milk). Specific gravity follows from the corrected reading.
Assumptions: the lactometer is calibrated at 15.6 °C; the 0.18-per-°C factor is the accepted linear approximation over the usual milk range.
Limitations: the correction is approximate outside 10–30 °C; a lactometer cannot separate the effects of fat, solids and added water — confirm with total solids and fat tests.
Rounding: corrected reading and correction to 2 decimal places; specific gravity to 4 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: Observed reading 30 at 20 °C. Correction = 0.18 × (20 − 15.6) = 0.79; corrected reading = 30.79; specific gravity = 1 + 30.79 ÷ 1000 = 1.0308.
Enter values above to see results.
Whole milk specific gravity is typically 1.027–1.033 at 15.6 °C; skim milk reads higher, watered milk lower. Tool 125 of 500 — GIFSQ
