Water, I guess. I boil the jars for 10 minutes without any sauce in them, including the lids to sterilize them. And then I boil them for about 35 minutes let them cool. And if I did it right, the seal should be good to go. 

 I'm not sure boiling is sufficient for botulism.  You might want to check on that.  A small pressure cooker would be sufficient but I think to protect against botulism you need higher temperatures. 

 I will take a look at that but so far all my years of canning I haven't gotten sick off of anything I've canned so I think I'm good but now you got me paranoid I am going to double check things 

 Sorry I don't mean to fuck with you.  But I mentioned it because I felt like I had to.  It may be the boiling is fine so long as its for long enough so the spores are deactivated.  

 Well I'm at about 430 feet above sea level and according to every chart out there boiling it for 35 minutes says you should be fine based on my elevation but maybe that's just for creating the seal. 🤔 

 Im sure the internet has a definitive answer, Im not an expert in this shit, I just know that when I can long term I use a pressure cooker and go hard.  But I'm probably just being overly cautious