“Chopped?” I hope you’re not being literal! All of the info so far is “on the money,” with the exception of no clarification of whether you mean you treated the lemons in the traditional way of “almost” cutting them into quarters from end to end or if you literally mean “chopped.” There should be NO bubbling or fermentation! Nearly every time I have preserved lemons I have had to add a pretty generous amount of extra lemon juice at the beginning to make sure the lemons are completely immersed. And do not skimp on the salt! And do not use iodized salt!
For “traditional Moroccan” (North African really) preserved lemons, we cannot get the type of lemon they use, or at least I can’t in Dallas, but Meyer lemons are pretty close. Thick skinned lemons that have a thick layer of pith (the white stuff) under the zest are not the ideal. BUT! Even if you used a really thick skinned lemon, the preserving process should not produce bubbles or fementation. And no shaking of the jar at any time!
Also, just for the record, I try very hard to find organic Meyer lemons because who needs to preserve pesticides? Store bought preserved lemons are very pricey when comopared to the cost of preserving your own, so give it another shot, and good luck!
And now I have a question for other “old hands” at preserving their own lemons. Have any of you EVER tried preserving other citrus? I’ve been looking for organic Valencia oranges for several years now to give them a try, but alas, Valencias are sooooo seasonal in my area that they’re gone in a flash, let alone “organic”! Or if I could ever find a tangerine/clementine with peels that aren’t too lose, I might try those. Anyone tried it? And I DO plan on trying limes some time soon.