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7 Simple Steps to a Foolproof Vinaigrette

By the editors of Cook's Illustrated

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The ingredient list is short and method is simple. So what's the problem?

Vinaigrette may be the most useful sauce in any cook's repertoire, because in addition to dressing greens, it can be used as sauce for chicken, fish, and vegetables that have been grilled, poached, or steamed.

The ingredient list is short and method is simple. So what's the problem? Basic vinaigrette doesn't stay together. By the time you pour it over greens and get the salad to the table, this emulsified sauce has broken and you end up with overly vinegary and oily bites of salad.

This is where our recipe for a foolproof dressing that won't break comes in.

We tested three emulsifiers—mustard, egg yolk, and mayonnaise—to find out which would hold the dressing together longest. This online video shows our experiment at work.


Using separate stand mixers fitted with whisk attachments, we created three vinaigrettes: We added 1/4 cup of vinegar to the bowl of each mixer, then added 1 tablespoon of mustard to one mixer, cracked an egg yolk into the second, and used 1 tablespoon of mayo in the third. Then we drizzled 3/4 cup of oil into each mixer over the course of 30 seconds, with the mixers running at medium-high speed. Finally, we placed all blended samples on the counter and tracked their progress at 15-minute intervals. As a control, we also made one vinaigrette in a stand mixer with no emulsifier.


The egg yolk vinaigrette was still stable after more than three hours, making it the runaway winner for stability. The vinaigrette with mayonnaise showed signs of separation after 1 1/2 hours, while the one with mustard started to break apart after only 30 minutes. The control began separating immediately and was almost completely separated after the first 15-minute interval.


Egg yolks contain a high percentage of lecithin, one of a group of fatty compounds known as phospholipids that act as potent emulsifiers, keeping oil droplets suspended within vinegar. Mayonnaise is made in part from egg yolk and therefore contains phospholipids, but a much smaller amount, so dressing made with mayonnaise was stable for a shorter time. The emulsifying component in mustard is a complex polysaccharide that is less effective than the lecithin found in egg yolks and mayonnaise.


Despite its superior stability, tasters rejected the vinaigrette made with egg yolk as too eggy. We ended up using ½ teaspoon of mayonnaise to emulsify our dressing and adding ½ teaspoon of mustard for flavor.


Our vinaigrette works with nearly any type of greens but is especially well suited to mild, tender lettuces. For a hint of garlic flavor, rub the inside of the salad bowl with a clove of garlic before assembling the salad. And the best part? Once you master this technique you can play around with various types of vinegars, oils, and seasonings to make dozens of different dressings.

1. Mince 1 shallot to yield 1 1/2 teaspoons.

2. Combine 1 tablespoon vinegar, shallot, 1/2 teaspoon mayonnaise, 1/2 teaspoon Dijon mustard, 1/8 teaspoon salt, and pepper to taste in small nonreactive bowl.

3. Whisk until mixture is milky in appearance and no lumps of mayonnaise remain.

4. Place 3 tablespoons extra-virgin olive oil in small measuring cup so that it is easy to pour. (You can also use a small bowl.)

5. Whisking constantly, very slowly drizzle oil into vinegar mixture.

6. If pools of oil are gathering on surface as you whisk, stop addition of oil and whisk mixture well to combine, then resume whisking in oil in slow stream.

7. The vinaigrette should be glossy and lightly thickened, with no pools of oil on its surface.

RECIPE FOR MEMBERS: Foolproof Vinaigrette

Now that you’ve seen how it’s done, follow our recipe for a salad dressing whose components stick together. Choose high-end oil and vinegar and whisk them together with a little mayonnaise for a well-balanced vinaigrette recipe that won't separate.

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