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Jul 13, 2013 10:03 PM

Chemistry Question about Sauce / Dressing

I make a potato salad with a unique dressing. It is two parts prepared mayonnaise to one part peanut butter (I used natural, chunky, but have had the same thing happen with Skippy creamy), with a splash of apple cider vinegar and some curry powder.

All of the ingredients are whisked together and end-up forming a lovely, smooth, satiny sauce. However, if I glance away for even a moment (as I did this afternoon), the sauce "breaks" in that the oils separate and the sauce looks curdled.

What is happening, chemically, when this occurs and is there anyway I can bring it back together?

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  1. It would seem that you are making an emulsion which is where fat molecules are suspended in liquid. If you make a standard vinaigrette and shake it will come together but will separate if you leave it. Your using mayonnaise which is also an emulsion but a stable one due to the egg yolks. I would assume then fat in the peanut butter and the vinegar are making an unstable emulsion like a vinaigrette. Adding an egg yolk or corn flour may help stabilize the sauce.

    This link may help.

    1 Reply
    1. re: Paprikaboy

      Thank you, Paprikaboy, for both the insight / explanation of what is chemically occurring and for the link (very helpful and I'm now poking around on the site). Much appreciated!

    2. It's an emulsion thing, I love using my immersion blender instead of a whisk, it seems to make a more stable emulsion.

      2 Replies
      1. re: wyogal

        Many thanks, wyogal - I'd never even thought of using my immersion blender (love that thing!), but it makes sense, because I've used it with other emulsions and you're right in that they do seem to be more stable.

        1. re: wyogal

          Agree, be more aggressive with the emulsion with a stick or regular blender. You'll integrate the ingredients better and help make the texture more even. Big difference in textures with the PB.

        2. Yeah, I think you're going to have to use egg, because the only other emulsifier I can think of at the moment is mustard, and that probably won't work well with peanut butter.