Add the dried sorrel, cinnamon stick, ginger slices, and cloves to a deep stock or soup pot.
Wash and cut the guava into pieces, and add it to the pot along with the dried orange peel. Some guavas can have a white, pink, or red interior. You may also use guava paste that can be found in Latino and Asian supermarkets.
Add the water and bring to a boil over medium-high heat. Reduce to a simmer and cook for 35 to 40 minutes.
Turn off the heat and allow the mixture to steep for at least 4 hours or overnight.
Strain the liquid using a strainer lined with cheesecloth, squeezing the sorrel and guava to extract all the juice and flavor.
Return the strained liquid to a pot, add the bay leaf and sugar, and bring to a boil.
Reduce to a simmer (immediately as it comes to a boil - explained in the video below) and cook for 60 to 70 minutes, or until reduced by at least one-third. For a syrup, reduce by two-thirds.
Remove the bay leaf. Allow to cool completely, then bottle and store in the refrigerator.