Nonreactive vessel, such as a half gallon wide mouth mason jar with a plastic lid
Ingredients
Brine fermented lemons
Organic lemons or meyer lemons don't use regular lemons
Kosher salt or sea salt As needed
Filtered water as needed
Instructions
Brine fermented lemons
Make a 3% brine solution by mixing 30 grams of salt for every 1000 grams of water.
Cut your lemons into quarters and pack into a large jar, such as a half gallon mason jar, or a couple quarts. Cover the lemons with the brine, weighing them down with an object in the jar like a clean stone to keep the lemons submerged under the brine. Allow the lemons to sit at room temperature and ferment for 7-14 days, or until sour to your liking.
Trimming
After the lemons are fermented, remove them from the jar, put them rind-side down on a cutting board, and, using a sharp paring knife, cut away the pith and seeds and discard. If you used the vacuum method, you can squeeze the capillaries and pith to extract fermented lemon juice.
From here, the lemons are shelf stable and can be held in the refrigerator, or water-bath canned in their brine if you used brine. Canning in brine will also tenderize the rind, which is a nice bonus. Do not can lemons in their juice, which could become bitter-save that for another fresh purpose like salad dressing.
Tenderizing the rind
Finally, you need to heat the rind long enough for it to become tender. My favorite way to do this is to seal in a vacuum bag and cook sous vide at 150 F for 2 hours, but you can also steam them.