Boiling water isn’t enough to kill a lot of hardier bacteria and fungal spores and so it’s certainly not “sterilized”, though it may be ‘sterile enough’ for your purposes. Water just can’t get hot enough and the “shells” are well insulated enough to survive for hours in those conditions.

However, they also become tougher once dehydrated and so simply placing them in a really hot stove has the same issue.

You simultaneously need more heat, pressure, time, and possibly some form of chemical attack to truly “sterilize” something.

Using a pressure cooker and a tiny amount of alcohol, ethanol, is usually enough to do the trick.

So many people way overuse the term “sterilize”.

For anyone unaware, “sterile” means zero life remaining, not “really clean”. You serilize things with a pressure canner and strict protocols or an autoclave (which is essentially a pressure cooker). With steam, you need 15 minutes at 121 °C or 3 min at 134 °C. Dry heat requires 2 hours at 160 °C.
There are a handful of other ways (like tyndallization), but not common or convenient.

For fermentation, you don’t need sterile unless you are working in a yeast lab or something like that where you are trying to grow up pure cultures. Sanitization or disinfection is good enough. Basically you want to kill enough of the bad bacteria/yeast that the good stuff out competes it.

Trying to get jars sterile for fermenting peppers is pointless because the peppers themselves are host to a huge heterogeneous population of bacteria and yeast, and you aren’t operating under a laminar flow cabinet or something crazy like that.

Yeah, you want them clean and sanitized, but it’s really all about controlling the probabilities. Higher salt concentration helps, being really careful about keeping things submerged helps, using a good airlock and relatively small headspace helps, and rejecting any peppers that seem suspect helps. Also, resist the urge to open the jars a whole bunch of times. Every time you do, you let in oxygen.

Also, OP, buy some pH test paper. It’s nice to be able to double check that the pH is in the right range once you think it’s done.

Yeesh. That’s a lot of work, but I guess it makes sense that properly sterilizing things isn’t easy.

I have a pressure cooker, but would be a bit anxious about putting glass inside it. Another user said they used Potassium Metabisulfite for beer and wine bottling. Would that be sufficient for sterilization, or would one still need high heat and pressure?