(*) One recipe makes about 6 jars of jam.
Day 1: Rinse the lemons and cut into narrow slices. Scoop out the seeds and wrap in a muslin bag. Place the lemon slices and the gauze bag in a large earthenware pot, glazed on the inside, and add half the water. Cover with a clean dish and leave at room temperature for 24 hours.
Day 2: Pour everything into a large stainless steel pot and bring to a boil over medium heat, then remove from the heat again. Pour the contents back into the stoneware pot and cool. Cover with a clean dishcloth and leave with the lid on for another 24 hours.
Day 3: Pour off the liquid. Place lemons and gauze bags in the large stainless steel pot form. Fill with the remaining water. Bring to a boil over medium heat. Make for about half an hour, until the zest of the lemon can be easily pierced with a wooden stick.
Remove from heat and strain, reserving the liquid.
Set the lemons aside. Pour the juice back into the saucepan, add the muslin bag and sugar. Bring to a boil, stirring until the sugar dissolves, then switch to medium heat. Leave open for about 30 minutes, until the mixture is viscous like syrup. Repeatedly mold the lemon slices to the syrup and make 30 to 40 min until the mixture has thickened and coats the back of a spoon.
Cover the gauze bag with de