Cut away the pineapple’s top and bottom and set aside. (See Recipe Notes.)
Cut away the rind of the pineapple and slice the fruit, removing the core. Store the fruit to enjoy later.
Chop the pineapple rind and the core into 1" to 2" pieces.
Place all the pieces into a one gallon jar. (You can also use two half-gallon jars.)
Drop the cinnamon stick into the jar.
Add the sugar into the jar and fill the jar with 8 cups of water.
Put the lid on the jar and allow the Tepache to ferment for two to three days out of direct sunlight in an area with a temperature of approximately 72°F (22°C). Once bubbles and foam form at the surface of the liquid, the Tepache is ready to strain.
Take a flour sack towel or cheesecloth and saturate it with cool water, then ring the water out of it as much as possible. Line a colander or mesh strainer with the damp flour sack towel or cheesecloth and place it over a large bowl.
Pour the contents of the jar into the lined colander or mesh strainer and allow the Tepache liquid to drip down into the bowl. (Do not discard the rind. See Recipe Notes.) Once the Tepache stops dripping, decant it into a bottle and place it in the fridge to chill.
Once chilled, enjoy the Tepache straight up or poured over ice. Tepache is best consumed within three days of making it.