How do I get homemade mayonnaise to taste like store bought mayonnaise?
I have to make both mayonnaise and aioli every day at my job. We sometimes do R&amp;D on off days and we spent quite some time trying to imitate our favorite gourmet mayonnaise. I think that we were successful, here are some tips:


Lemon juice comes closer to that crisp tartness that I taste in even cheaper mayonnaise. Try using the juice from lemons, limes, or both and see where that gets you.
The store bought brands don't taste like mustard, but let me emphasize that mustard is vital to getting you closer to that taste. There is a specific "tang" to store bought mayonnaise that doesn't come from the acid -- you can get very close to this tang with mustard. I use a good quality dijon when I make mayonnaise and the difference is noticeable. Keep adding dijon in small amounts and observe the change in taste. I end up 2 - 3 tablespoons to my batch.
Experiment with fresh garlic and/or garlic and onion powders.
Try adding white pepper instead of black pepper and see where that gets you.
I add a little water at the end. I find that it tones down some of the intensity of the acid and dijon.


Also, you don't have to add your acid in the beginning. In fact, I almost always add mine after the initial "setting" of the emulsification. It is easier to control the thickness and flavor of my mayo; I use my acid for my first thinning and then add oil to adjust from there.