Why Is My Dressing Separating?
Because oil and vinegar don't naturally mix — separating is what they do. A little Dijon or honey helps them stay together, and if it splits, you just shake it again.
It's supposed to separate
Oil and water-based vinegar want to pull apart. A vinaigrette holding together is a temporary truce, not a permanent state — so don't worry when it splits in the fridge.
An emulsifier helps it hold
A teaspoon of Dijon mustard or honey, or a little finely grated garlic, binds the oil and acid so they stay blended much longer. That's why almost all of my dressings have a little Dijon.
Technique matters
Add the oil slowly while whisking, or shake hard in a sealed jar. Cold oil straight from a cold fridge separates faster — let it come to room temperature and shake.
Store dressing in a mason jar and separating stops being a problem — ten seconds of shaking and it's good as new.