How to make Mexican-style fermented salsas at home

Fermentation: the secret to salsas with depth

Fermenting chiles is nothing new in Mexico. Before refrigerators existed, fermentation was a fundamental method of preservation. Salsas such as chile macho from Colima, some artisan pickled chiles and certain regional salsas use natural fermentation to develop flavors that cannot be obtained in any other way.

In recent years, fermentation has enjoyed a global revival. Products such as kimchi, sauerkraut and kombucha have become popular. And now, fermenting chiles to make hot salsas is on the rise, with brands such as Tabasco (which ferments its chiles for 3 years) leading the way.

The good news: making fermented salsas at home is surprisingly easy, requires few ingredients and the result is infinitely superior to any shop-bought salsa.

What is lacto-fermentation?

Lacto-fermentation is a process in which Lactobacillus bacteria (naturally present on vegetables and in the environment) convert sugars into lactic acid. This acid:

• Preserves food naturally
• Creates complex flavors (acidity, umami, depth)
• Produces probiotics beneficial to gut health
• Develops aromas that do not exist in fresh chiles

The process is simple: chiles + salt + time = culinary magic.

The equipment you need

You do not need specialist equipment:

• Glass jars: Mason jars or preserving jars. Ideal size: 500 ml - 1 litre
• Salt: sea salt without iodine or additives (iodine inhibits fermentation)
• A weight: something to keep the chiles submerged in the brine (a smaller jar filled with water, a clean stone or fermentation weights)
• Cloth or a lid with a valve: to cover the jar while letting the gases escape

Fermented habanero-and-carrot salsa

This is one of the most popular fermented salsas and the best to start with. The carrot brings a natural sweetness that balances the extreme heat of the habanero.

Ingredients:

• 10-12 habanero chiles (orange or red)
• 3 medium carrots, peeled and chopped
• 4 garlic cloves
• 1 small onion in quarters
• Sea salt without iodine (3% of the total weight of the vegetables)
• Filtered water (chlorine-free)

Process:

1. Prepare the brine: weigh the chiles, carrots, garlic and onion. Calculate 3% of that weight in salt. For example: if the vegetables weigh 500 g, you need 15 g of salt.
2. Cut: halve the habaneros (wearing gloves), slice the carrots into thick rounds and quarter the onion.
3. Pack: place everything in the glass jar, pressing down firmly.
4. Brine: dissolve the salt in filtered water at room temperature and pour it over the vegetables until they are completely covered.
5. Submerge: place the weight on the vegetables to keep them under the brine. Anything left exposed to the air may develop mould.
6. Cover: cover with a cloth held in place with a rubber band, or a fermentation lid with an airlock.
7. Ferment: leave at room temperature (20-25°C) for 5-7 days. You will see bubbles: a sign that fermentation is active.
8. Blend: when the flavor is tangy and complex (taste on day 5), drain the vegetables (reserve the brine) and blend them with a little of the brine to the desired consistency.
9. Bottle: store in clean bottles in the fridge. It keeps for months.

Fermented serrano-and-tomatillo salsa

This fermented green salsa is perfect for tacos, enchiladas and chilaquiles. The fermentation gives it a gentle acidity that complements the heat of the serrano.

Ingredients:

• 15 serrano chiles
• 6 tomatillos (or unripe green tomatoes)
• 1/2 white onion
• 4 garlic cloves
• 1 bunch of cilantro (just the stalks, the leaves are added later)
• Sea salt (3%)

Follow the same process as the recipe above. Fermenting the tomatillos creates a natural tangy flavor that is amplified by the lacto-fermentation. After blending, add the fresh cilantro for contrast.

Fermented salsa macha

Traditional salsa macha is made with chiles de árbol fried in oil. This fermented version takes the concept to another level:

1. Ferment chiles de árbol and morita with garlic for 7-10 days
2. Drain and fry the fermented chiles in oil with sesame seeds and peanuts
3. Blend partially (it should keep some texture, not be smooth)

The result has the umami depth of fermentation plus the toasted, oily notes of traditional salsa macha. It is addictive.

Fermented manzano chile with fruit

The manzano chile (or perón) has a fruity flavor that is hugely enhanced by fermentation. Combine it with fruit for a unique salsa:

• 8 manzano chiles (or habaneros as a substitute)
• 1 ripe mango
• 1/2 pineapple
• 3 garlic cloves
• Sea salt (2.5% - less salt because of the fruit sugar)

Ferment for 3-5 days (the fruit ferments faster due to its high sugar content). The result is a sweet-sour, spicy, complex salsa that goes wonderfully with tacos al pastor or any pork dish.

Tips for successful fermentation

• Chlorine-free water: chlorine kills the beneficial bacteria. Use filtered water or leave tap water to stand for 24 hours so the chlorine evaporates.
• Salt without iodine: iodine inhibits fermentation. Use sea salt or rock salt.
• Temperature: 20-25°C is ideal. More heat = faster but less controlled fermentation.
• Everything submerged: anything left out of the brine may develop mould.
• Mould vs. kahm yeast: a thin white layer on the surface (kahm yeast) is harmless, just remove it. Green, black or pink mould IS dangerous: discard everything.
• Taste daily: from day 3, taste the brine. When the flavor is tangy and complex to your liking, move everything to the fridge to stop the fermentation.

Fermentation in Mexican tradition

Mexico has a rich fermentation tradition that goes well beyond salsas:

• Pulque: a fermented agave drink, predating tequila by millennia
• Pozol: fermented maize dough from Chiapas
• Tepache: a drink of fermented pineapple peel
• Colonche: fermented prickly-pear wine
• Tejuino: a fermented maize drink from Jalisco

Fermenting salsas connects with this ancestral tradition and, at the same time, aligns with modern trends in healthy and sustainable eating.

Experiment with fermentation and discover flavors you never imagined possible. Find fresh chiles in Mexican shops and more inspiration in our recipes. Visit our blog to keep learning about Mexican culinary techniques.