Emulsification has been understood practically in Western cooking since at least the 18th century, when mayonnaise emerged in the French culinary tradition (the Menorca origin story) and hollandaise in the 19th century court kitchen. The chemistry — lecithin as emulsifier, droplet size as stability determinant — was formalised by food scientists in the 20th century. Segnit's contribution is showing that these are not separate recipes but a single technique family with cultural variables.
An emulsion is fat dispersed in water (or water in fat) in droplets small enough to remain suspended rather than separating. The stable emulsion — from mayonnaise to hollandaise to vinaigrette to Caesar dressing — is one of the most versatile preparations in cooking and one of the most misunderstood. It is not primarily a flavour technique; it is a **distribution architecture** — the emulsion creates a medium in which fat-soluble and water-soluble compounds are simultaneously accessible to every bite.
Emulsified sauces serve as flavour-distribution architectures — they carry fat-soluble aromatics into contact with every element of the dish they dress. A well-made aioli distributes its garlic, olive oil, and acid evenly across every component it touches. This is the reason emulsified dressings and sauces taste more complex than the sum of their ingredients: the emulsification creates simultaneous access to multiple flavour dimensions.
- **The emulsifier:** Lecithin (in egg yolk), mustard phospholipids, and garlic starch are the common emulsifiers in culinary preparations. They work by being simultaneously fat-soluble and water-soluble — they sit at the interface between fat droplets and water phase, coating each fat droplet and preventing coalescence. - **Droplet size determines stability:** The smaller the fat droplets, the more stable the emulsion. Vigorous, sustained whisking (or blending) breaks the fat stream into smaller droplets. Adding fat too quickly produces large droplets that coalesce — the emulsion breaks. - **Fat addition rate:** Oil must be added to the egg yolk drop by drop initially, while whisking continuously, until the emulsion is established. Once stable, the addition rate can increase. The critical phase is the first 15–20% of oil — this is where the emulsion architecture is established or fails. - **Temperature management:** Cold emulsions (mayo) require room-temperature ingredients — cold egg yolk cannot flex its lecithin molecules to coat fat droplets efficiently. Warm emulsions (hollandaise) require the butter to be warm but not hot — above 70°C, the egg yolk protein denatures and the emulsion becomes a scrambled egg. - **Water phase contribution:** Lemon juice, vinegar, or water in the base provides the continuous water phase into which fat is dispersed. This water phase also carries acid, salt, and water-soluble flavour compounds that complement the fat-soluble aromatics in the oil or butter. - **Rescuing a broken emulsion:** A broken mayonnaise (fat and water separated) can be rescued by starting with fresh egg yolk in a clean bowl and whisking the broken emulsion into it drop by drop — treating the broken emulsion as the fat source. This works because the lecithin from the original emulsion is still active; it has merely lost its architectural arrangement. Decisive moment: The first tablespoon of oil — the emulsion either forms here or it doesn't. Watch for the mixture thickening and turning opaque. Transparency means the emulsion has not yet established; opacity means the fat droplets are being successfully coated. At opacity, the addition rate can increase slightly. Sensory tests: - **Sight:** A stable emulsion should be opaque, smooth, and uniform in colour. Any translucent streaks indicate incomplete emulsification. A broken emulsion shows obvious oil pooling or greasy streaks. - **Feel:** Properly emulsified mayonnaise should coat a spoon in a smooth, cohesive layer and hold its shape when dropped from the spoon. A broken emulsion runs off immediately. - **Taste:** The emulsion should taste smooth — the fat and water components perceived simultaneously, not sequentially (first oily, then acidic). Sequential perception is the sign of a poorly formed or slightly broken emulsion.
- A single egg yolk can emulsify up to 250ml of oil — the lecithin content is sufficient for this ratio. Beyond this, the emulsion becomes unstable. - For flavoured mayonnaise, add fat-soluble flavouring compounds (chilli oil, truffle oil, porcini oil) as part of the oil phase — they distribute perfectly through the finished emulsion. - Segnit's key insight: once you understand emulsification, romesco, tahini sauce, and hummus are revealed as the same technique — it is only the fat source (olive oil, sesame paste) and the emulsifier (bread, chickpea starch) that differ.
- Emulsion breaks immediately → fat added too quickly at the beginning; or egg yolk too cold - Emulsion is thin and runny → insufficient whisking; droplets too large for stable suspension - Hollandaise scrambles → butter too hot; or heat too aggressive during whisking; egg protein denatured - Aioli tastes bitter → garlic over-processed; excessive cell rupture released bitter compounds from the garlic
LATERAL COOKING — PROVENANCE EXTRACTION