First, start with 2–5 “golden” variety whole pineapples. Most companies use the same “golden” moniker for a range of great pineapples, all descended from the MD-2 pineapple variety. (Don’t use canned pineapple juice for the fermentation, but you can use it for sweetening the drink afterward.)
Don’t clean the outsides of the pineapples—not at all—and don’t peel them. (Besides the yeast and bacteria, the skin adds its own flavors that make tepache unique.) Just remove the green spiky crowns, then cut the pineapples into chunks. Use a food processor to grind up the pineapple into a coarse slurry, something like chunky-applesauce-meets-oatmeal. If you grind it too small, the filtering step will be more difficult.
At the start of fermentation, add one 8 oz (227 g) cone of piloncillo (or panela) sugar for every 2 pineapples used. Put the sugar and pulp in a 5-gallon (23-liter) bucket (not a carboy or corny keg). Add 1 cup (237 ml) of water per pineapple used. Find a lid of some kind—a piece of wood works well, with a towel between the bucket rim and the lid to let gas escape and keep bugs out.
Wait 5 to 10 days for fermentation to complete, stirring every day. The juice will naturally fall out of the pulp, and the pulp will float. Once a day, mix that pulp back into the juice to get more contact between the fermenting juice and the skin. Before mixing each day, you can pull samples of the fermenting juice from the bottom of the container to taste and determine whether the fermentation has finished. Note: It will be zero gravity. You won’t be able to determine the starting gravity, thus you won’t be able to determine total ABV, but it should finish between 5 and 10 percent ABV.
When fermentation completes, stop mixing and wait about 2 days for the pulp to float up and settle into a fairly firm cake atop the finished tepache. Use a piece of tubing to siphon the tepache from the bottom of the bucket. Scoop all the pulp into a big mesh bag, cheesecloth, kitchen towel, or strainer/colander, and squeeze as much juice from the pulp as you can. (By this point, you’ve introduced a lot of air and wild bugs floating in the air into your finished tepache. Don’t stress: Tepache is not a clean process. Sanitation and oxidation are not concerns—save those worries for your brew days!)
Now, you have a fully dry, fermented pineapple juice, likely with some bits floating in it. It may taste terrible, with all kinds of volatile acidity (such as vinegar-like acetic acid), various sulfuric compounds (like hot plastic), and usually some acetone aromas. This is all to be expected—don’t panic.
Here comes the secret: Make a “tea” of cinnamon, cloves, and allspice with some water in a saucepan on the stove. (Spices such as these and nutmeg have a storied history of use to cover up wine faults, and they work like magic in tepache. I prefer making a tea instead of adding the spices to the fermentation, so that you can pour in the right amount of finished tea to taste.) Use 1 cinnamon stick, 3 cloves, and 3 allspice balls per 2 pineapples used. Add water to 1 inch above the spices and simmer for 1 hour or so. Remove the spices and cool the tea.
Add an equal amount of pineapple juice as you have finished tepache. Buy it in a can or run some whole pineapples through a juicer, but don’t buy concentrate. Mix equal parts dry, alcoholic tepache and fresh, sweet pineapple juice, add the spice tea to taste, and serve it immediately.
Once you’ve blended in the sweet juice, there’s no way to consistently stabilize tepache—at least, not on a home scale. At Reverend Nat’s, we pasteurize our kegs and bottles. Campden tabs and potassium sorbates won’t work, nor will keeping it cold (short of freezing).