How to Emulsify a Vinaigrette or Homemade Mayonnaise

Classic vinaigrette

Rough ratio: three parts oil to one acid —vinegar or lemon—. Salt and mustard in the bowl bottom; mustard helps emulsify. Whisk acid with salt then add oil in a thin stream while whisking hard.

Use mild oil for delicate salads; intense olive oil can bitter if over-beaten. Taste and balance with honey or a pinch of sugar if needed.

• 3:1 oil to acid as base.
• Mustard as emulsifier.
• Oil in thin stream while whisking.

Homemade mayonnaise

Room-temperature yolk, oil drop by drop while beating until emulsified, then a thicker stream. One yolk holds about 200 ml oil. Lemon or vinegar at the end adjusts acidity.

If it breaks —separates— beat a fresh yolk in a clean bowl and add broken mayo drop by drop as if it were oil.

Temperature and tools

Room-temperature ingredients emulsify better. Hand whisk or immersion blender in a tall narrow jar work. Oil must go slowly at first.

Eggless aioli uses pounded garlic and extreme patience; it is less stable. With egg, mayo keeps days refrigerated covered.

• Yolk and oil at room temperature.
• Start with drops, then stream.
• Rescue broken with fresh yolk.

Common mistakes

Oil too fast at the start breaks emulsion. Bowl with water or cold yolk. Raw egg mayo: use fresh eggs and consume within days, or pasteurize yolks if risk is a concern.

Vinaigrette separates on standing: whisk again before serving.