Work out fat content from analysis instantly with clear inputs, formula shown and shareable results.
Gravimetric fat determination weighs the extracted and dried lipid: fat percentage is extracted mass divided by sample mass times 100. Reporting on a dry basis removes the effect of moisture variation, which is essential when comparing batches or against a specification written on dry matter.
Fat content
Fat % = (flask + fat - empty flask) x 100 / sample weight
Dry basis
Fat on dry basis % = fat % x 100 / (100 - moisture %)
Soxhlet or Randall extraction for free fat, acid hydrolysis first for dairy and bound-lipid products, and Rose-Gottlieb or Gerber for milk. Method choice changes the answer, so it must be stated.
A cheese at 25% fat and 45% moisture has 45% fat in dry matter, which is the legally defined basis for many cheese standards. Wet-basis figures cannot be compared across different moisture levels.