Scrub the melon in cool water. Cut in half and scoop out and reserve the seeds. Cut the melon into chunks and reserve the rind. Transfer the rind and seeds into a gallon jar. Top off with the melon chunks or save them for another purpose.

In a small pot, toast the cinnamon over high heat, stirring constantly, until fragrant, one to two minutes. Add the water, piloncillo shavings and a pinch of salt and bring to a boil. Once the sugar is mostly dissolved, remove from the heat and let cool to lukewarm.

Pour the spiced piloncillo syrup over the rinds and add more water until the rinds are completely covered. Position a small jar, fermentation weight, or water-filled resealable baggie over the melon rinds to submerge them and prevent mold from forming at the surface. To prevent bugs from finding their way into the jar, cover it with a breathable, tightly woven cloth secured tightly to the mouth of the jar with a rubber band or twine. Set the jar aside at room temperature in a shaded area and allow it to ferment until there is foam on the surface and the texture of the liquid is slightly viscous, two to four days. Stir and taste daily. The tepache will begin to bubble vigorously between one and five days. It should start to taste sweet and tangy in two to three days.

Discard the white foam that has developed on the surface.

When you like the flavor, strain the tepache over a cheesecloth-lined funnel into clean bottles, leaving 2 inches of head space at the top. You can drink it right away or store it in the refrigerator. (You can even reuse the peels and start a second batch). The tepache will keep for a few months in the refrigerator, however, it tastes best soon after it's ready to drink. If you leave the bottles in the refrigerator, vent them every 2 weeks to release built-up carbonation.

Serve well chilled.