Fermented Hot Sauce (Ají-Style)
South America's answer to sriracha - bright, funky, and alive with flavour. This fermented hot sauce brings complexity that store-bought versions can't match, with the wild fermentation creating layers of umami and tang alongside the heat.
What you'll need:
- 500g fresh chillies (jalapeños for mild, habaneros or ají amarillo for heat - or a mix)
- 6-8 cloves garlic, peeled and roughly chopped
- 1 small onion, roughly chopped (optional, traditional in some styles)
- 2-3 tablespoons fine sea salt (3-4% of total weight)
- Filtered water as needed
- 1 teaspoon sugar or honey (optional, to balance heat)
- Juice of 1-2 limes (added after fermentation)
Equipment:
- 750ml-1 litre glass jar
- Fermentation weight or small jar to keep solids submerged
- Blender or food processor
- Fine mesh strainer or muslin (optional, for smooth sauce)
- Clean bottles for storage
Method:
- Prepare your chillies: Wash chillies thoroughly and remove stems. You can leave seeds in for maximum heat or remove some for a milder sauce. Wearing gloves is wise if using hot varieties. Roughly chop the chillies.
- Make the brine: Weigh your chillies, garlic, and onion (if using) together. Calculate 3% of that weight in salt. For 500g of solids, that's 15g salt. Dissolve salt in enough filtered water to cover the vegetables (usually 250-300ml).
- Pack your jar: Place chopped chillies, garlic, and onion in your jar. Pour brine over to cover completely. Everything must be submerged to prevent mould.
- Weight and cover: Place a fermentation weight on top. Cover with a lid (loosened to allow gas to escape) or cloth secured with a rubber band.
- Ferment: Keep at room temperature out of direct sunlight. You'll see bubbles within 24-48 hours. Ferment for 5-7 days for bright, fresh heat, or 10-14 days for deeper, funkier flavours. Taste as you go.
- Blend and finish: When fermentation reaches your preferred flavour, strain out the solids, reserving the brine. Place solids in a blender with fresh lime juice and sugar/honey if using. Blend until smooth, adding reserved brine to reach your desired consistency - thick for a paste, thinner for a pourable sauce.
- Strain (optional): For silky-smooth sauce, push through a fine mesh strainer. For rustic texture, leave as is.
- Bottle and store: Pour into clean bottles. Refrigerate - it will keep for 6+ months, continuing to develop flavour.
The science: The lactobacillus bacteria that ferment the chillies don't just create tang - they actually break down some of the capsaicin, making the heat more rounded and less sharp. The fermentation also creates glutamates (umami) that add savoury depth you can't get from fresh chilli sauce.
My tip: Don't be tempted to add vinegar during fermentation - let the wild bacteria create their own acidity first. The lime juice at the end provides brightness without interfering with the fermentation process. If your sauce is too hot, blend in some fermented carrot or sweet red pepper to mellow it out.
Serving suggestions: Drizzle on tacos, eggs, grilled meats, or anywhere you want heat with complexity. Mix with mayonnaise for an incredible burger sauce, or stir through soups and stews for instant depth.
