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How to fix separated vinaigrette

Shake it in a jar or whisk it hard just before serving. To make it hold together for longer, whisk a little mustard into a clean bowl and slowly whisk the dressing into it.

How you can tell

  • Oil sits in a layer on top of the vinegar
  • The dressing looks clear and runny rather than cloudy
  • It coats salad unevenly, with oily patches

Why it happens

Vinaigrette is an emulsion of oil and vinegar, which naturally don't mix. Shaking or whisking breaks the oil into tiny droplets spread through the vinegar, but without anything to hold them apart they soon join up again and the oil floats to the top. This is called a temporary emulsion. Ingredients such as mustard, honey and egg yolk act as emulsifiers, helping the droplets stay suspended for longer.

How to fix it

Option 1Shake or whisk again

  1. Put the dressing in a jar with a lid and shake hard
  2. Or whisk it vigorously in a bowl
  3. Use it straight away

Option 2Add an emulsifier

  1. Put a small spoonful of mustard in a clean bowl
  2. Pour in the separated dressing in a thin stream, whisking all the time
  3. Taste and adjust the seasoning

Next time

  • Whisk the mustard, vinegar and seasoning together first, then add the oil slowly
  • Include a little mustard or honey to help it hold
  • Make it shortly before serving, or shake it again just before using
General kitchen guidance, not food-safety advice. If food may be unsafe, for example undercooked meat or anything left out too long, follow the Food Standards Agency and throw it away if in doubt.