I was making a vinaigrette to marinate some tomatoes, and it congealed to the consistency of a pudding. It is the first time I have tried this recipe. I whisked it all together, then left it on the counter overnight for the flavours to meld before pouring it over the tomatoes, and this morning there was still some oil on top, with the rest of the vinagraitte a very thick mass underneath. So I whisked again, and the rest of the oil got emulsified, but I was left with "vinaigrette pudding." Any clues as to why it congealed like this? The ingredients list is:

  • 1 cup Extra Virgin Olive Oil
  • 1/4 cup Balsamic Vinegar
  • Squirt of Dijon Style Mustard for Emulsifier
  • 4 Tablespoons Sugar
  • 1 teaspoon Salt
  • 1/2 T Freshly Ground Black Pepper (I toasted it before grinding)
  • 2 t Chopped Fresh Oregano
  • 18 whole Basil Leaves (chiffonade)
  • 2 T Chopped Fresh Thyme
  • 2 cloves Garlic, Minced Finely
  • Experiment suggestion: Does the same happen if just the first five ingredients are treated like that? BTW, such an effect if reproducible might be useful, given we all sometimes want salad dressings to be sticky and thick :) Commented Aug 15, 2016 at 9:35
  • I'll try that and let you know. Commented Aug 15, 2016 at 13:21
  • I made it again with the first five, and it congealed again. Commented Aug 16, 2016 at 12:42
  • How cold was it in your kitchen overnight / this morning?? Olive oil gets thick at colder temperatures (most noticable if you put it in the fridge). If that's the problem, warming it slightly should get it back to normal.
    – Joe
    Commented Aug 16, 2016 at 19:32
  • Kitchen was not the least bit cold - temp might have gotten down to 70 overnight, but definitely no lower, and probably warmer. I do not have AC, and temps have been in the mid-80's daytime. Commented Aug 17, 2016 at 15:58

2 Answers 2


It is unusual for this to happen. One possibility I see is for your mustard to contain a thickener which then also emulsifies the whole sauce. Remember, most emulsifiers will thicken even when present in tiny amounts. If the conditions are right for some other reason (maybe you mixed with an electric appliance or shaked very vigorously) it is not that strange that it can happen.

My suggestion is to try it without the mustard and see if it thickens. If it doesn't, shop around for mustards from thickener-free brands. If it still happens with them, then they worked too well! Normally the mustard is a mediocre emulsifier and allows the vinaigrette to combine, but does not make a stiff emulsion. You could try less mustard then, or adding it at the end and gently stirring with a fork without whipping at all.

  • I will try it one more time without the mustard. The recipe did not call for it - I added it because the tomatoes need to marinate for several days, and I wanted to make sure it stayed emulsified during that time. As for mixing, I just whisked it by hand. Commented Aug 17, 2016 at 15:56

Did you change the olive oil brand between the successful and thick preparations? The web used to have a lot of articles on how we cannot trust olive oils (even the more costly ones) as they seem more often than not to be diluted with inferior oils. Some have flavorings added. Expert tasters cannot tell the difference, except that your health probably can.

A grocer told me that Chile and California have very strict laws governing olive oils and they inspect them regularly.

I'm wondering if an inferior oil would cause that thickening?

Sorry if this is not the case, but your problem is a puzzlement.

  • 1
    It was the same olive oil (and vinegar) both times. After the second batch, I'm thinking that it is a reaction between the vinegar and the sugar, because I whisked it up, then let it sit, and when I checked a while later, most of the oil had separated, and the vinegar was getting thick. I whisked it again, and checked it a bit later, and oil had separated out again, and the vinegar was thicker. This went on for several cycles, and after several hours, it was at pudding consistency again. Commented Aug 17, 2016 at 15:53
  • Adding to above - I'm not sure what you mean by "successful." It thickened both times. Commented Aug 17, 2016 at 16:00

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