I make it by hand all the time, even with yolks right out of the fridge. The oil has to be room temp, but who's isn't? I always add a bit of mustard and for me, the beating of the yolks initially with the other ingredients before any oil goes in should get the emulsion going and there's no problem adding the oil. It's always thickened, never broken and no more than 1/2 cup oil per yolk. Also, after watching the video of Jacques Pepin on the page below making mayonnaise, I realized that the "drop by drop" was a myth and I can whip it up in no time by hand. He adds it in big glugs and it emulsifies perfectly. Also, to watch him purposely break it and fix it is like watching Dumbledore battle Voldemort. http://www.foodandwine.com/articles/how-to-make-mayonnaise#video I also agree with @ChrisBelgium that all olive oil makes a bitter mayonnaise.