From Jar to Verde Fresco: My Rustic Green Chilli Sauce

Every now and then, a ferment surprises you. This one started on 19 February 2026 with a 750 ml jar, a handful of green chillies, some carrot, garlic, and eight black peppercorns. Twenty-four days later, it became this — a rustic fermented green chilli sauce that is tangy, thick, and wholly its own.

The Ferment Journey

On 19 February, I packed the jar and left it to do its work. My kitchen sits between 14 and 20°C — a gentle, unhurried rhythm that suits a slow ferment well — ideal conditions for a proper fermented green chilli sauce. By the third week, the chillies had softened, the brine smelt tangy and lively, and a thin white film had formed on the surface.

Kahm yeast — what it is and what to do

That thin white film is kahm yeast — a harmless surface yeast that's common in vegetable ferments, particularly in warmer conditions. It's not mould. Mould is fuzzy and often coloured; kahm yeast is flat, white, and slightly wrinkled, like a fine skin on the surface of the brine. It won't harm the ferment or the finished sauce, but it can introduce a mildly bitter or off flavour if left unchecked. Simply skim it away with a clean spoon, make sure everything is submerged, and carry on. The ferment underneath is doing exactly what it should.

A little blue tinge had also appeared on the garlic — another harmless quirk of the acids at work, and one I've written about before. I skimmed the film, ensured everything stayed submerged, and continued to watch.

Blending Your Fermented Green Chilli Sauce

On 14 March, the jar was ready. I removed the bay leaf, drained the vegetables, and blended the chillies, carrot, garlic, and black peppercorns — keeping it rustic, thick, and full of body.

To balance the peppery after-kick and brighten the flavours, I stirred in a splash of brine, a squeeze of lemon juice, a touch of honey, and 25 ml of apple cider vinegar. A thin slick of olive oil on top will slow oxidation if you want to seal the surface — in my fridge, it isn't strictly necessary, but it's a good habit.

Tasting Notes

This fermented green chilli sauce is bright, tangy, and pleasantly peppery, with a subtle sweetness from the carrot and a warm depth from the black peppercorns. The green chillies give it that fresh, grassy character that defines a good Verde Fresco. Rustic and unapologetically thick, it pours slowly and clings to whatever it touches — tacos, eggs, grilled vegetables, or straight from the spoon if you're that way inclined.

Storage and Use

Stored in the fridge, this fermented green chilli sauce will keep for two to three months. Over time, the flavours will round out and deepen. If you like, stir in a little more lemon juice or vinegar when serving to lift it again.

Reflections

Fermentation is as much about patience as it is about ingredients. From jar to sauce in just under a month, this batch captures the quiet satisfaction of watching simple vegetables transform into something tangy, vibrant, and alive. There's no rush — just curiosity, attention, and the pleasure of tasting something that is wholly your own.

This recipe is part of my Fermentation Hub – a growing collection of live cultures, pickles, and preserves. It also appears in my Curry Recipes hub.
All recipe hubs → Recipe Hubs
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