Whenever you read the instructions for vinaigrette, it always says to add the oil in a slow stream after having mixed up the vinegar with the other ingredients like spices/herbs/garlic/mustard/whatever in order for the dressing to emulsify.
I found that if you whisk the vinaigrette long enough, it'll emulsify regardless of which you put in first. In fact, the way I learned making my first salad dressing was to start with the oil, then add lemon juice, s&p, herbs, garlic, sour cream. Whisk till desired consistency. No prob.
no it's not a myth - it will help you emulsify - indeed if you whisk long enough it will emulsify no matter how you add the ingredients, but adding the oil in slowly helps
furthermore, any spices, herbs, etc. you add will help emulsification, especially mustard/mustard powder
if you really want to see the difference try whisking vinegar into oil without any fanciness, and then try the add-oil-slowly-to-vinegar-as-you're-whisking method, and do both WITHOUT any spices etc. - just oil and vinegar. With the adding-in-oil-slowly method, you're pretty much done when you finished adding the oil, whereas with your method the mixture will EVENTUALLY emulsify with enough whisking - is my prediction correct?
And, peanut, do you know?--isn't it true that it's even more important (if not essential) to add the oil in a slow stream if it's going into eggs or a mixture with eggs?
I've heard that, but it's not something I've done more than once or twice in my life and I don't remember. :-)
I always cheat and add even a touch of mustard to any savory mixture I'd like to emulsify. Just a small bit, if I really don't want to taste it, and more, if I do.