Emulsions
aïoli
aioli · A cold, garlic‑forward egg‑yolk emulsion dressed with olive oil. The classical aïoli of Provence is built on raw egg yolk, crushed garlic, salt and olive oil — no mustard, no lemon, no vinegar — yielding a dense, golden sauce with an assertive, pungent character that is thinned with its own cooking liquid from the accompanying poached vegetables.
The formula
1 large yolk : 250 g fine olive oil (≈1:12 by weight)
1 yolk emulsifies ~250 g oil. Add oil in a very slow, steady thread once emulsion is nucleated. Traditional garnish for 4–6 portions: poached potatoes, carrots, green beans, hard‑boiled eggs and salt cod. The cooking water from these vegetables thins the aïoli to dipping consistency and is the defining feature of the complete dish.
Identity
- Raw egg yolk as sole emulsifier — no commercial mustard required
- Fine, fragrant olive oil (not extra‑virgin punch); mild fruitiness keeps garlic centre‑stage
- Garlic crushed to a paste with salt, not minced or grated
- Emulsion built drop by thread, never poured
- Thinned with vegetable cooking water, never plain water, to stay coherent
Ingredients
| Binder | large egg yolk | Sole emulsifying agent; must be at room temperature. |
| Fat | fine olive oil (10–15° Érissel or similar mild fruitiness) | Not robust extra‑virgin; the garlic must dominate. |
| Aromatics | garlic cloves, peeled | Typically 4–6 cloves for 1 yolk; crushed to a smooth paste with coarse salt in a marble mortar. |
| Seasoning | coarse sea salt | Added to garlic paste; draws moisture, aids grinding. |
| Acid | white wine vinegar or lemon juice (optional in classical recipe) | A few drops sharpen flavour; strictly optional — traditional aïoli is built without it. |
Method
- 1Pound garlic and coarse salt to a smooth, sand‑free paste in a marble mortar.A coarse paste prevents gritty garlic bits from tearing the emulsion and ensures even distribution throughout the sauce.
- 2Add the egg yolk and whisk vigorously to combine the yolk with the garlic paste.Dispersing the yolk in the garlic paste creates the initial aqueous phase into which oil will be emulsified.
- 3Add oil drop by drop while whisking constantly at moderate speed, establishing a nucleated emulsion before switching to a thin, steady stream.Drop‑by‑drop addition in the initial phase prevents the oil from pooling and allows lecithin‑coated droplets to form gradually, creating a stable matrix.
- 4Continue adding oil until the emulsion is thick, glossy and will hold its shape on a spoon.Classical aïoli is intentionally dense; it will be thinned later with cooking water.
- 5Thin the sauce with the hot cooking water from the garnish vegetables, adding 1 tbsp at a time, whisking between additions.Hot starch‑laden water emulsifies with the sauce without breaking it and gives a pourable, dippable consistency while keeping the sauce warm enough to serve alongside the vegetables.
Techniques that matter
Mortar‑and‑pestle grinding
The traditional stone method physically ruptures garlic cells more completely than knife work, releasing allicin and juices that contribute to both flavour and emulsion stability.
Drop‑by‑drop oil incorporation
The rate of oil introduction governs droplet size and hence emulsion stability; rushing this step is the primary cause of a broken sauce.
Starch‑water thinning
The residual starch in vegetable cooking water acts as a secondary emulsifier and thickener, allowing dilution without phase separation.
Variations & derivatives
Catalan allioliCatalonia / Valencia
Traditional version uses no egg yolk at all — only garlic and oil, worked to a paste. The resulting sauce is denser, more volatile and requires a powerful mortar technique. Modern restaurant versions often add yolk.
aïoli provençalProvence
Full recipe includes a pinch of saffron dissolved in warm water, giving a pale gold colour and floral bitterness; served with grilled fish or langoustines.
aïoli moroArles region
Adds pressed sheep’s‑milk whey (recuite) folded into finished aïoli for a tangy, slightly grainy consistency.
sauce au choixFrench brasserie tradition
When lemon juice and Dijon mustard are added to aïoli, it becomes a general‑purpose all‑purpose emulsion used as a sauce for grilled meats, fish and crudités — essentially indistinguishable from a garlic mayonnaise.
Used in these dishes
Substitutions
- egg yolk → Dijon mustard (½ tsp per yolk) — Mustard provides allyl isothiocyanate as an emulsifying agent and adds sharp flavour, but changes the character from pure aïoli to a more universal garlic mayonnaise.changes result
- olive oil → mild vegetable oil or half grapeseed — Produces a blander, more stable emulsion with higher smoke tolerance for warm applications; acceptable for warm aïoli sauces but a compromise in the classical cold version.changes result
- fine olive oil → extra‑virgin olive oil — Excessively grassy or pungent oil overwhelms the garlic and destabilises the emulsion through excessive polyphenols; not recommended for the base sauce.changes result
Troubleshooting
Emulsion will not form; oil pools and separates immediately
Oil added too quickly before yolk is nucleated, or yolks are too cold (below 15 °C), preventing lecithin from hydrating properly. → Start fresh: begin with yolk alone, add oil drop by drop, keep yolks at room temperature. A second yolk whisked in can sometimes rescue a stalled emulsion.
Sauce is too thick and stiff to dip
Too much oil incorporated relative to the aqueous phase; classic aïoli is intentionally dense but requires thinning. → Whisk in hot vegetable cooking water 1 tbsp at a time until pourable; if already broken, start a new emulsion in a clean bowl and slowly whisk the broken sauce into it as if it were oil.
Garlic taste is harsh and acrid rather than mellow and fragrant
Garlic not ground to a smooth paste; cell walls ruptured by aggressive mincing release allinase enzymes that produce harsh sulphur compounds before cooking. → Use a mortar and grind with salt for 3–5 minutes until silky; or blanch whole garlic cloves twice (2 min boils) before crushing to temper the flavour.