Actually very easy

Fermented hot sauce

The beliefHot sauce is assumed to be either a factory product or a risky laboratory exercise in fermentation.

The truthPeppers, salt and water. Hold the salt at 3% and the bacteria do the rest; a week later you have a sauce.

20 minutes of work, 7 days of waiting

How to make it

What you need

500 g fresh chillies
4 garlic cloves
30 g non-iodised salt
1 litre non-chlorinated water
60 ml white vinegar, at the end
A wide-mouthed glass jar and a weight to hold things down

How the engine read this list (5 lines)

500 g	Fresh chillies	pepper
20 g	Garlic	garlic
30 g	Non-iodised salt	salt
1000 g	Non-chlorinated water	water
61 g	White vinegar	vinegar

An empty weight means that line could not be turned into grams — either the amount is open ("to taste") or the ingredient has no record here. Neither enters the sum as zero; they do not enter it at all.

Stir the salt into the water until it dissolves completely. That is a 3% brine: 30 g to a litre. Do not judge the salt by eye — the whole ferment depends on the ratio.
Trim the stems, halve the chillies and pack them into the jar with the garlic, then pour the brine over. Everything must stay under the liquid.
Weigh it down, close the jar loosely and stand it at room temperature out of direct sun. Loose matters: the carbon dioxide it gives off builds pressure.
From the second day you will see bubbles. Taste it on day seven: it should be sharply sour and fruity with the raw pepper taste gone. You can keep going to day fourteen if you like.
Strain the chillies, blend them with half the brine, add the vinegar and bottle it, using the brine to set the consistency.

Why it works

The salt in the brine is a selection tool. At 3% most spoilage bacteria cannot work while Lactobacillus can — so the salt is not a preservative but a filter deciding which microbe wins. The bacteria turn the peppers’ sugar into lactic acid, and the pH falls from about 6 to 4.5 in the first 48 hours and to 3.4–3.6 by day seven. In that range pathogens cannot grow. The capsaicin that makes it hot does not change through any of this; what changes is the raw green taste of the pepper, which the ferment rounds off and leaves fruity underneath. Letting the finished sauce down with vinegar is a safety margin rather than a flavour choice: it fixes the pH below 3.5 and covers any contamination picked up on the way from jar to bottle.

The rough sum

1611 grams going in

198 kcal in total

100% of the mass has figures behind it. This is the sum of what GOES IN rather than of what comes out. Wherever something evaporates, drains or ferments the two differ: a kilo of milk is 150 g of cheese.

Diets it qualifies for

Gluten-free Vegan Vegetarian Lactose-free

Storage & shelf life

How long it keeps

Fridge, in a closed bottle: 6 months
With vinegar added, below pH 3.5: 12 months in the cupboard
Fermenting jar, under brine: Goes on maturing for 2 more months in the fridge
Freezer: Pointless — the acid is already doing it

During the ferment, lactic acid bacteria turn the peppers’ sugar into acid and the pH drops to around 3.5 by itself. From that point the sauce preserves itself. The first three days are the critical ones, though: any pepper that floats above the brine will grow mould. Weigh them all under with a glass or a clean stone.

When to bin it A thin flat white layer on the surface is kahm yeast: skim it and carry on. A fuzzy, coloured (green, black, pink) or raised patch is mould and the whole jar goes. The smell should be sharply sour; if it smells rotten or drainlike, throw it away.

History

Where it comes from

Fermented pepper sauce is as old in the Americas as the pepper itself. Tabasco has been made since 1868 in Louisiana from peppers held three years in salted barrels, and the method has not changed. Korea’s gochujang, Indonesia’s sambal oelek, North Africa’s harissa — each found the same principle independently: hold the pepper in salt and let the acid arrive by itself. In Turkish cooking the nearest relative is isot, salted and left in the sun, and the hot pepper paste of Antep.

The knack

If you use tap water, leave it uncovered overnight: chlorine kills the very bacteria that start the ferment.
Wear gloves. Capsaicin dissolves in fat and soapy water does not take it all off your hands; in an eye it burns for hours.
An airlock on the jar makes life easier but is not required; a loose lid does the same job.

Fermentation