Soxhlet extraction is a classical laboratory method for determining fat content in food samples by repeatedly cycling a solvent through dried material to dissolve lipids, then quantifying the extracted fraction by gravimetry.
In trade practice
Laboratories apply Soxhlet extraction to cereals, pulses, nuts and processed foods when a reference fat value is needed for specification compliance or nutrition labelling. The method requires careful sample drying beforehand, as residual moisture suppresses solvent uptake and understates fat content. Results are reported as crude fat on a dry-matter or as-received basis; buyers should confirm which basis applies when comparing supplier certificates of analysis.
In a specification
A product specification referencing Soxhlet extraction should name the applicable ISO or AOAC method, state the reporting basis (dry matter or as received) and set the maximum or declared fat content against which the result is assessed.