what the heck happened to my mayo (home made)??

Ok, been making this aoli/mayo for a while. NEVER had a problem with it. A couple drops of lemon, an egg yolk and then drizzle oil (usually olive) till I get the amount and taste I want at the time.
EXCEPT… this time it’s been a total and complete fail and I’ve NO idea what happened.
It won’t stay set. It’s not that it doesn’t set. It does. Goes exactly how it’s supposed to but when I go back to it it starts to dissolve. I try to re-set it (drop or two of water and add the “mess” to it till it sets again). Currently it’s a liquidy mess with what looks for all intents and purposes like curdled milk (like when it forms that skin on top).
Anyone have any ideas?
Finally gave up and made a different batch and that one worked perfectly fine, so I’m stumped what happened.

It’s tricky to get it to stay very long without an emulsifier. A bit Mustard is traditionally used in homemade mayo, for that as well as a bit of extra zip.

that’s the thing. i’ve never used one. I use nothing but lemon, yolk, oil and dash of salt. I’ve had it stay solid for days (in fridge naturally).
This is the first time I’ve seen it like this and I’m flumoxed. Would egg white cause this perhaps? Only thing that occurs but never had it happen so don’t know.

Egg yolk does the same thing.

Did your olive oil expire? How old is your egg?

Yes, and there is a lot more lecithin in egg yolk than there is in mustard.

I’m confused. The whole batch emulsified properly, then you put it in the fridge and a few hours later it was oily slop? I’ve never had that happen. I have had a batch start out fine, then half way through the blending turn to slop. I dunno. I can usually make mayo fine, and then on random occasions it just screws up. Maddening. I have learned, however, that you can start with a new egg, add the slop to it, and re-blend, and that will work.

The way it was explained to me is–mustard helps emulsification because it is essentially little tiny granules that, when stirred with oil, break the oil up into smaller and smaller orbs, which makes the emulsification work better.

At my cafe, I would not bother to drizzle the oil when I made house vinaigrette; I would dump it all together and whiz it up with the great big whizzy stick (forgot what that’s called), as there was enough mustard in the recipe to emulsify San Francisco Bay.

What kind of olive oil did you use and how old was it?

From what I understand from reading the mayonnaise section in “On Food and Cooking”, extra virgin olive oil is notorious for causing delayed mayonnaise disintegration, due to some emulsifier-like properties of degraded olive oil molecules that displace yolk molecules as emulsifiers, and then later, coalesce into oil droplets. Old and improperly stored oil is most prone to this problem.

The recommended solution is to use refined olive oil, or something like soybean or sunflower that has had the funky emulsifier-like molecules refined out.

Is it possible that there was some minor contamination to your utensils, bowl, or mixer that might cause an emulsion to break? Though I worked for a company that makes a major brand of mayo, I don’t know what contamination would cause it to break. The other possibility is that the egg yolk was somehow compromised and did not have the emulsifying effect.

Egg white is not an issue. It doesn’t do much for the emulsion, but it doesn’t hurt it either. Major brands of mayo include egg white.

Send it to the Mayo Clinic for testing.