Mayo didn't thicken - oil in too quick?

[CarolineW]

Mine usually works, with the odd exception.  The ingredients all being at room temperature is key - assuming that the room temperature isn't 'Damn hot' - when it also seems inclined to fail.  The other thing which has caused me problems is if my TMX bowl LOOKS clean, but actually isn't grease free, 'cos I just self-cleaned it without detergent.  Other than that, it's always worked perfectly.  I've never failed with the German recipe, which someone posted on the mayo thread.  That's the one I use now (although not at the moment, of course!)

[UnConundrum]

While I've made a mayo without mustard (and usually do), I wouldn't leave it out of a recipe that calls for it.  Mustard is an emulsifier and contributes to the mayo setting up.

In addition to its flavoring and nutritional values, mustard offers rather unique functional properties. Mustard is used as an emulsifier, a water binding agent, and for texture control in many foods. In mayonnaise, mustard flour stabilizes oil-in-water emulsions while in meat products ground mustard acts as a binding agent which allows for easier slicing.

Mustard absorbs liquid in foods including fat and vegetable oils at rates of 1.5 times its weight in salad oil and 2 times its weight in water. This liquid control prevents undesirable separation and aids in product consistency.

http://www.minndak.com/Mustard.htm