Vegetables ferment

Fermented chilli mash & hot sauce

Intermediate

Chillies fermented with salt, then blended into a tangy hot sauce.

Temperature: 18–24 °C
Time: 1–4 weeks; Longer = more sour and complex.
Salt: Mash commonly 2–5% of chilli weight; brine 3–5%; No NCHFP-tested hot-sauce ferment exists; err towards the higher end and confirm pH.
Acidity (safety control): pH 4.6 or below — ideally under 4.0 before cold storage; Acid made by lactic bacteria is what keeps vegetable ferments safe; 4.6 is the regulatory boundary for acid foods. Check with pH strips (narrow range) or a calibrated meter. Smell and taste are not a safety test.

Timeline

Stage 1: Chop & saltstart · about 30 min
Hands-on — Gloves on
Stage 2: Fermentfrom 30 min · about 14 days
Fermenting / waiting — 18–24 °C
Stage 3: Blend & bottlefrom 14 days · about 1 h
Hands-on — Add vinegar, check pH
Stage 4: Refrigeratefrom 14 days · keeps about 12 weeks
Cold storage — Fridge, months

Ingredients

Fresh chillies, stems removed
Salt by weight
Optional: garlic, carrot, onion
Vinegar (for the finished sauce)

Equipment

Jar with weight or airlock lid
Gloves
Blender
Kitchen scale
pH strips or meter

Steps

Wear gloves. Roughly chop chillies (and garlic or carrot if using).
Weigh and mix with salt (mash), or cover with brine.
Pack into a jar, press under the liquid, weight it down.
Ferment at 18–24 °C for 1–4 weeks until sour.
Blend with some of the brine and vinegar to taste; check pH is 4.6 or below (ideally lower).
Bottle and refrigerate.

Is it working?

Bubbling, sour fruity smell
pH 4.6 or below

Smell & texture: Sour, fruity and hot; colour dulls slightly.

Signs tell you it's fermenting, not that it's safe: never rely on smell or appearance alone.

Safety, mould and discard rules

Mould or yeast?

A thin, flat, white or cream film on the brine surface is usually kahm yeast: skim it off promptly, because it feeds on the acid and can raise the pH. Anything fuzzy, raised, or coloured (blue, green, black, pink, orange) is mould: discard the whole batch, including the brine. If you can't tell which it is, discard.

Storage

Refrigerate the finished sauce. Homemade sauces are not shelf-stable unless made by a tested acidified process.

Shelf life: Refrigerated and acidified, usually good for a few months; watch for mould or fizz.

The science: what's happening

Lactic bacteria sour the chillies over one to several weeks, adding depth and acidity. Blending with vinegar afterwards lowers the pH further.

Organisms

Wild lactic acid bacteria

Troubleshooting

Mould on floating bits: Pieces above the brine grow mould — if it is fuzzy mould, discard the batch; next time weigh everything under.

A dish (not a ferment) gone wrong? Try Recipe Rescue.

Learn more

Sources

General Information on Fermenting — National Center for Home Food Preservation
21 CFR Part 114 — Acidified Foods (pH 4.6 boundary) — US Code of Federal Regulations (eCFR)
Potential Hazards with Fermented Foods — Association of Food and Drug Officials

Guidance changes: check the source for current wording. Original text; figures quoted from the sources where stated.