Bring 6 cups (1.5 L) of water to a boil.
Meanwhile, wash lemons and remove zest with a peeler or zester.
With a knife, remove the white peel (albedo) and slice the lemon. Remove the seeds roughly.
Discard the white peel and seeds in the compost, as these would make the beverage bitter.
When the water is boiling, remove it from the heat source and add the sugar, brown sugar, zest, and lemon slices. Stir well to dissolve the sugar and allow it to cool.
Once the mixture is warm, transfer all of it into the jar.
Pour cold water into the jar until you have 12 cups of beverage.
In a small bowl, rehydrate the yeast in about ¼ cup (60 ml) of warm water. Let it stand for 5 minutes, then add to the jar.
Cover the jar with a cotton cloth and secure it with the rubber band.
Let the sima ferment for 24 hours at room temperature.
Using a sieve, or a filter bag, strain the sima to remove the zest and flesh of the lemons.
Add 2 raisins to each bottle (optional).
Fill the bottles with sima up to 2 inches from the rim. Close the bottles tightly.
Let the bottles ferment at room temperature for 12 hours.
After 12 hours, test the pressure of the beverage by quickly opening and closing the bottles. If it is not fizzy enough, let it ferment longer.
When the raisins have risen to the surface and there are enough bubbles to your liking, put the bottles in the fridge.
