Extraction

Extraction is the process of drawing flavour, colour, aroma or other soluble compounds out of an ingredient and into a liquid, fat or other medium. In cooking, extraction occurs during stock-making, brewing, steeping, infusion, soaking, pressing and some forms of blending.

Factors that affect extraction

• Temperature: heat can increase the rate at which compounds dissolve, although excessive heat may damage delicate aromas or extract unwanted bitterness.
• Time: longer contact often increases extraction until the desired balance is reached.
• Particle size: smaller pieces expose more surface area and can extract more quickly.
• Solvent: water, fat and alcohol dissolve different compounds.
• Agitation and pressure: stirring, blending or pressure can accelerate contact between the ingredient and extraction medium.
• Ingredient composition: maturity, freshness and processing affect what can be extracted.

Examples in professional cooking

Simmering bones and connective tissue in water extracts flavour and gelatin for stock. Brewing coffee extracts soluble compounds from ground beans. Infusing vanilla into cream transfers aromatic compounds into the dairy, while making herb oil extracts fat-soluble flavours into oil.

Extraction versus infusion

Extraction is the broader process of removing compounds from an ingredient. Infusion is one method of extraction in which ingredients steep in a liquid or fat to transfer flavour and aroma.

Chef’s tip: Choose the extraction medium and time for the desired flavour. Over-extraction can produce bitterness, harshness or unwanted plant flavours, especially with delicate herbs, tea and coffee.

Key distinction: Extraction describes the transfer of soluble compounds from an ingredient; it is not limited to simmering or stock production.