Hello dear friends!
I make a sauce with strong Dijon mustard (water, mustard seeds, vinegar, salt, citric acid, potassium metabisulfite) and Italian olive oil (oil of olives). Usually it goes very easily, and despite the concentrated mustard needs an important dilution, adding the oil in two steps suffices easily.
I tried to add all the oil in a single step and it failed. Long stirring with the fork couldn't get that little mustard in the oil. Adding more and more mustard (up to a first-step proportion I'd say) didn't help.
Do you have an explanation? Inverted emulsion, viscosity too low, needs air bubbles, others...?