Density vs. Specific Gravity of Milk

By determining the specific gravity (SG) of milk the following information can be obtained.

• An indication of adulteration of milk with added water.
• If the fat percentage is available the solids-non-fat (or total solids content) of the milk can be calculated.

Definition

Specific gravity is the relationship of the mass of a specific volume of a substance to the mass of an equal volume of water at the same temperature.

Density is measured as mass per volume (g/ml) at a specific temperature.

The specific gravity of milk at 20 °C is ± 1.030 and is determined by the relative proportions of fat (SG = 0.93), water (SG = 1.0) and solids-non-fat (SG = 1.614).

Kind regards,
Leon the Milkman