Homemade Preserved Lemons- Olive Oil?

Thank you so much for everyone's responses! As Pagine said it would be a nice holiday gift..I wanted to go ahead and share my pictures with you that I gave the girls in my family for Christmas! I used organic Meyer lemons with raw Himalayan sea salt that contained no anti-clumping agents to keep out any extra chemicals!! Thanks again! -Kelly

I keep mine refrigerated and there is so much salt that I don't think any other preservative is needed. I suspect it's a personal preference just as adding spices or cinnamon stick. I don't add the olive oil because it solidifies in the refrigerator.

I have always been successful with lemons, salt, lemon juice and water. However, my ex mother in law (Italian) would put a layer of olive oil on top of anything in a jar to act as a preserving barrier.

It is, I believe, the Sephardic (Jewish) version. My friend who married a Sephardi fellow did it that way, but following Paula Wolfert, I make with only salt, lemons and juice. Either way is fine.

Here's a little video on this site that shows you how easy it is... all you need is lemon, salt and a jar. (Nice holiday gift.)
http://food52.com/blog/5953-how-to-preserve-lemons

I guess to act as some type of preservative, but most recipes I've seen just require adding lemon juice to top off the lemons in the jar. There's a lot of info in this older Hotline thread about the recipe (without olive oil) from Paula Wolfert's cookbook, Foods of Morocco.
http://food52.com/hotline/12262-a-question-about-a-recipe-moroccan-carrot-salad-with-harissa