Aioli — from the Catalan all i oli (garlic and oil) — is traditionally made from only garlic and olive oil, with no egg. The emulsification is achieved through the garlic's starch and mucilage acting as the emulsifier in place of egg lecithin. This is one of the most technically challenging preparations in Catalan cooking — the emulsion is extremely unstable without egg and requires patience and very slow oil addition. Modern aioli uses egg yolk, producing a more stable (though less traditional) preparation.
**Traditional all i oli (garlic only):** - Garlic cloves (blanched to moderate pungency), salt — pounded in a mortar to a complete paste with no pieces remaining. - Olive oil added drop by drop while pounding/whisking — each drop must be completely incorporated before the next. - The emulsification is achieved through the garlic's own protein and mucilage content — fragile and easily broken. **Modern aioli:** - Garlic + egg yolk + lemon juice + olive oil — the egg yolk's lecithin provides a far more stable emulsion. - The oil added in a thin stream while whisking — standard emulsification technique. **The break:** If the emulsion breaks (oil separates): start with a fresh egg yolk in a clean bowl, add the broken aioli drop by drop while whisking — the fresh egg yolk's lecithin re-emulsifies the mixture.
Spain: The Cookbook