I make a mayonnaise by slowly whisking a cup of extra light olive oil into two eggs yolks and a tablespoon of dijon mustard. The mayonnaise is not as thick as store bought mayo but it is thick enough to spread.

However, when I stir in solid ingredients to make an aioli the emulsion suddenly becomes very thin. It doesn't break, but it turns into a liquid. This has happened with minced garlic and with chopped clams. Sometimes after stirring in the solid ingredients it looks as if there are bubbles coming out of the emulsion.

What causes this, and how can I prevent it?

  • 2
    Removing all the discussion of terminology. (And James, feel free to call it whatever you want to call it; there are regional variations in usage of "aioli" and none is more right than any other.)
    – Cascabel
    Sep 19, 2016 at 16:39
  • You're not adding any acid?
    – Niall
    Sep 19, 2016 at 17:19
  • I usually add around a teaspoon of white wine vinegar or a few squeezes of lemon juice at the end
    – J Cameron
    Sep 19, 2016 at 17:45
  • 2
    @James Cameron the acid should be in there from the start (then the oil added gradually while blending) - it's necessary to form the emulsion correctly and isn't there just for taste
    – Niall
    Sep 19, 2016 at 17:49
  • 4
    @James Cameron - pretty sure it's a problem with your mayonnaise recipe/technique rather than what you're adding. Adding the acid at the end is one problem but it could be other things - oil quantity might be a bit low and/or not beating it hard enough (try immersion blender).
    – Niall
    Sep 19, 2016 at 18:27

2 Answers 2


I'm going to step out on a limb based on experiences I've had. I suspect that adding garlic and or chopped clams after you have emulsified your other ingredients is simply adding moisture and making your mayo/aioli thinner. (Especially since you said that it doesn't break.)

I would suggest putting your garlic or clams in at the beginning with your other ingredients before you emulsify with the oil. If you still find it to be too thin you can whisk in another whisked egg yolk or a little more oil to get your desired consistency.

Re the comment about acid, I don't use any. Also there would likely be vinegar in the Dijon mustard, so you are not sans acid.

  • I'll try that next time and see what happens
    – J Cameron
    Sep 20, 2016 at 17:30

Yeah i have the same problem with mayonnaise for potato salad... when i add other things to it, like spring onions, a bit of feta, or dill, it goes really really thin. Last time, it actually complete separated... wasn't too appetising having potatoes sitting in a pile of oil!

It's heartbreaking when you've waited overnight while potatoes cool and what was a perfect looking mayonnaise is completely destroyed :/ Have been reading a bit about it, and I think "cold" might be a problem. Also different mustards make a difference to the emulsion... one site reckons whole grain is the best to use as the emulsifying agent is most prevelant in the husk of the mustard seeds (i.e. in the "whole grain"). Dijon was a close second.

But for me i think i might have my fridge too cold... I usually keep the mayonnaise in fridge overnight and ice crystals might be forming. Or I keep the spring onion and other ingredients in the fridge, so they too might form ice crystals.

As a side note: I wouldn't use olive oil for mayonnaise, it's far too bitter but I think I might be especially sensitive to bitter tastes (e.g. i think the world is weird for liking beer ha!)

  • Different olive oils have different flavors. And as the standards for labeling of olive oil is much more lax in the US, there have been stories of importers sending low quality (and possibly rancid) oil to the US, but labeling it 'extra virgin'. You should also beware of rough agitation of olive oil -- what might work fine when hand-whisked might be bitter and foul if put in a food processor or blender.
    – Joe
    Oct 26, 2017 at 13:51
  • I also notice a big difference between “extra virgin” and “extra light” olive oil— the extra light works ok in mayo, but extra virgin does not imo
    – J Cameron
    Oct 27, 2017 at 2:21

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