Naturally fermenting salsa makes a richer and more complex flavor than simply adding vinegar or lime juice, but it does take a little patience. I love tart salsas and sour foods with a bite. Grandma and Grandpa Schwemm on my dad’s side passed on a tradition of sauerkraut, and my mom’s family loves chile. How could chiles fermented like kraut not be my favorite food?

Fermented salsa is a source of pro-biotic microorganisms, recently rediscovered as essential for the digestive system. Home fermented foods probably provide more active and diverse cultures than what comes in a capsule at great expense.

Chiles for this preparation can be fresh or roasted or even dried. I’ve used everything from dried chiltepines to fresh Big Jims and sweet peppers. Hot, fleshy chiles like Jalapeño, Serrano, Guero, Wenks Yellow Hot, and Sinahuisa are ideal.

Sometimes I meticulously seed and dice the chiles, sometimes I only cut off the stems and coarsely chop in the food processor.

I usually add onion, garlic and herbs, as the season and whim direct.

Add salt to the salsa, 2% of vegetables’ weight. This is roughly 1 teaspoon non-iodized salt per cup of diced vegetables, more or less. Salt slows and directs biological activity to make the food more delicious. Lactobacilli thrive in salty environments where other organisms cannot, and the lactic acid they make further inhibit harmful bacteria. Since this is a condiment, I don’t mind it a little salty. There are enough beneficial bacteria on the fresh produce and in the air, so no starter culture is necessary.

If the chiles are not very fleshy or I want a thinner sauce, I add a little brine made with 2 teaspoons salt per cup of water. Thinning the sauce is a good idea when the chiles are very hot!
Put the salsa in a jar with a weight on top, keeping the pieces of chile submerged in exuded juice or brine. I use a smaller jar as a weight.

Cover the tower with a tea towel to keep out dust and insects, and keep at room temperature.

How long before it’s ready? Test daily in warm weather to see if it is sour enough for your taste. In winter, the process is slower, taking up to a couple weeks. If white mold forms on the surface, skim off the top. It is harmless. If the mold is any color other than white, or below the surface of the liquid, discard the whole batch. Better safe than sorry.
When the salsa is tart and delicious, it can be eaten as is or pureed. For a smooth salsa, it can be strained. Sometimes I add fresh herbs or minced I’itoi onion tops.

Store fermented salsa in the refrigerator with an airtight lid.
Chef Molly Beverly from Prescott, Arizona suggested fermenting a sauce from Mano Y Metate Pipian Rojo, so I have some of that going now. I can’t wait to taste it!

For more details about fermenting food, see Sandor Katz’s The Art of Fermentation. For an encouraging primer on safely fermenting food, find Wild Fermentation also by Katz. This is one of my all time favorite cookbooks.