How would I jar a sauce for keeping at room temperature without adding loads of vinegar or sugar? I'd like to make and sell jars of my mum's satay sauce at our local food markets. 

I'm trying to figure out the jarring process so it can be stored at room temperature and not make anyone sick or worse.

My experience in jarring/canning is minimal but I've done some research and would love to get some of your thoughts on my process. 

I'm aware of botulism, so the ingredients of concern are fresh chillies, garlic, onions and belacan (salted shrimp paste).

These are fried with peanut oil.

There is sugar and vinegar in the mix. 

There is a good amount of sugar however it's definitely not 50% like jam or anything. 

The amount of vinegar is not a huge amount (should I ph test this? how and what ph would I look for?)

The rest is peanuts and dried spices. 

These are the steps I'm taking at the moment:


Sterilize jars and lids in preheated oven @ 140c for 20 mins.
Fry fresh ingredients at high temp.
Slow cook remaining in large pot at low temp.
Fill jars while sauce is hot.
Put filled jars in preheated oven @ 140 for 30 mins with lid loosely on.
Remove and tighten lid.


When cooled, the lids pops down and is sealed.

The jars are from a local supplier and have confirmed with them that they can be cooked. 
(I've tested this process about 3 times with higher heat and the jars withstand it).

How safe is my process? 

What have I done wrong, or what can I change/improve?

Should I add some kind of preservative?

I'm open to all suggestions. My goal is to have it kept safe at room temp for at least a month (more is better :) )

Currently, when I hand out test samples I ask people to keep it in the fridge and eat within a week.

Sorry about the long question but I just want to share her amazing sauce and not make people ill.
You cannot use an oven for canning - while the oven itself can reach temperatures higher than 100 degrees C, it is difficult to get the internal temperature of the contents of the jars up to the same temperature. You'd be better off pressure canning, and  @Chris_H has already shown where you can read up on the technique in the comments to the question.

It might be useful to provide a quick explanation why using an oven is not reliable. Please note that I am in no way suggesting that OP's 140C is either the correct temperature or the only condition needed for safe canning.

Assuming that your contents are capable of being heated to 140C at atmospheric pressure for now, in text-book ideal conditions (assuming perfectly conductive glass), it would take 54 minutes to heat a jar of it of 10cm diameter and 10cm tall form 100C to 140C. 30 minutes is just too short.

At atmospheric pressure inside your 140C oven, your sauce will not reach too much above 100C since it is mostly made up of water. Vapourising water keeps temperature fairly constant at that, at least initially. As more and more water is evaporated, eventually, you might reach 140C, but your sauce would also be dehydrated with a very significant reduction in volume. For practical purposes, you will not see 140C for a few hours and not before your sauce is ruined. The only way to overcome that is by raising the pressure and thus the boiling point of water. This is why sterilisation needs an autoclave or at least a good pressure cooker with as high a pressure rating as possible. In any case, I have not come across a consumer type pressure cooker that would offer 3.6 bar or 52 psi to attain 140C boiling point.



edit

@rumtscho's comment below made a good point that the 140C mentioned here seemed to suggest that it was the right temperature for canning. Just to clarify, I was using OP's temperature just to illustrate the point that it would be impossible to attain that in a common oven without pressurisation. As for the need for pH control and other important conditions for safe canning, I have not attempted to address them here.