Day before: boil 3 litres of water and add to a large bowl, the day before making your ferment. Leave in a window to dechlorinate for around 24 hours (or use distilled water).

Day of ferment: sterilise an (approx 1.4 L) fermentation jar, lid, fermentation weights and table knife. I.e. boil for 20 minutes OR use a sterilising solution (you must rinse this off with boiled water though!).

Wash your hands for 20 seconds, dry with paper towels. Make a 3% brine by dissolving 1.5 level tbsp (30g) in 1 litre of the dechlorinated water.

Wash the pepper, chilli and any other veg in the dechlorinated/distilled water. Peel the garlic cloves (don't crush).

Roughly chop the chillies and remove the seeds/calyx, leaving most of the pith.

Mix the cloves and chopped chilli/pepper add to the sterile fermentation jar (with any other fruit/veg you want to ferment).

Add enough brine to cover the chilli mix (leave a gap of an inch at the top, it expands!), use the sterile knife to gently move the chilli etc, to release any air pockets. Pop the sterile fermentation weight on top, to hold chilli/garlic etc below the brine.

Screw on the fermentation lid (i.e. with valve to let out gas). Keep on the side (out of direct sunlight) for (at least) 5 days, at room temperature. The brine should become cloudy, and gas bubbles appear, as fermentation occurs (it takes a couple of days to really get going)! Keep the lid on for at least 5 days, to keep out (bad) bacteria/mould and oxygen (it's anaerobic fermentation we are wanting).

After 5 days you can start to test the brine to see if it's acidic (1 week is about right usually).Taste to see if it's sour/tart (clean spoon) and/or use a clean pH meter (it MUST be below pH 4.6, ideally below pH 4). If you want to do a longer ferment (i.e. up to 2 months) then do not open the jar until this time has passed, to keep out undesirables/oxygen If it goes mouldy, or doesn't ferment, bin it!

Making the sauce: when the pH is low enough and/or required ferment time passed, strain the ferment (keeping the brine).

Add the ferment solids to a good food processor/blender (removing bay leaf, large whole spices etc) plus 1 cup of (saved) brine. Also add lemon/lime juice, onion and any herbs/fruit/sweeteners/extras. Blend to desired consistency.

Check pH and add 0-3 tbsp cider vinegar, as required, to get the pH to below 4 (pH 3.4 is best). If pH 3.4 or lower, omit vinegar.

Return to the fermentation jar (best to wash this up first) and mature in the fridge for 3-6 weeks.

Once matured, heat the sauce to 83C (boil), then simmer for 10 minutes (to pasteurise), with the pan lid on.

Once pasteurised blend in 1/2 tsp xanthan gum (you can add more than 1/2 tsp, a pinch at a time, if desired consistency/thickness is not yet reached) using a hand blender.

Bottle hot, in sterilised bottles. Flip upside down to kill germs on the lids.

You can also keep 1-2 bottles 'live', in the fridge, but ensure you don't cap them or they might explode.