Slice peaches into 6 sections each. Discard the pits. In a small pot set over medium heat combine 8 slices of peach with the panela and 1 cup water.
Bring the mixture to a simmer and continue to cook for 10 minutes, stirring occasionally to ensure that panela has dissolved completely.
Pour into a large carafe and top with 4 cups water and the lemon juice. Stir to combine. Refrigerate for at least 3 hours to allow flavors to meld.
Add a fresh peach slice to each glass before serving.