While lemons are present during medieval times, I have not yet run across a recipe for preserving them with salt that dates from that time. There are a bunch that use sugar or honey, but that would render them useless for my uses. With school right now, I have not had time to do more than a cursory search, so it is possible that one does exist. Packing meat and other items in salt to preserve them was done in many areas, so it could be argued that this is using a period technique on an item that is not specifically mentioned.
If you search on-line you can find a ton of recipes for preserved lemons. Some of them add spices as well, but I chose to just do salt and lemons this time. I picked both Meyer and Eureka lemons, but I have only done the Eureka lemons so far. I kept them separate because Meyers are actually a lemon crossed with a orange, and are much sweeter. I did not follow a recipe, because the sizes of lemons vary, and this is so simple, that it seemed silly to measure anything.
1. Wash the lemon, and cut off any imperfections from the skin.
2. Cut off the end. Since I knew I would be squishing them in the jar, I made this a wide enough cut that it would expose more of the pulp.
3. Quarter them without cutting through to the base. I cheated a bit on this last part since some of the lemons were very big, and I was using narrow mouth quart mason jars. On the large lemons, I cut them fully in half, then partially quartered the half.
4. Using a spoon pack the slices and all exposed areas with salt, and place them in the jar. As you add more, squish them into the jar releasing the juice.
5. Some of the recipes suggest adding lemon juice to top them off. For the time being I have held off on this, so I can see how much they settle. I used a tamper to squish them, so I am not expecting to be able to fit many more, but it may happen. If I can't fit any more in, I will top off with more juice from the lemons, then set them aside for a month to cure.
Things I learned:
1. I'm already well aware of how thorny lemon trees are, so I managed to avoid any cuts. However those cuts I did not realize I already had on my hands made sure I knew they were there, and how much they appreciated my antibacterial and drying treatment of them.
2. If the lemon is at all a close fit for the mouth of the jar, point the cut part down. Otherwise the lemon juice and salt escapes in a spectacular fashion splashing things you might not enjoy.
3. It takes a lot of lemons to fill a jar when you squish them. For five jars I have used about 60 lemons. This is actually pretty cool, because I barely made a dent on either tree.
If I you want some, please let me know, because the trees are already budding again. *sigh*
To use them, rinse the salt off, and either chop the complete lemon, or remove the pulp, and just chop up the skin.