When canning tomatoes with a pressure cooker -
 

- at what pressure and for how long do you process them after exhausting and pressure has been reached?

The guidelines have changed since the 1972 Micromatic book of 10 minutes at 5 pounds of pressure.

Right now I am using 10 pounds of pressure for 15 minutes.

Jar size and elevation affect canning times. There are lots of sources available where you can match your circumstances to time and pressure.
I'm relieved to be taking this year off from canning because I overdid things last year and still have tomatoes and tomato sauce in jars and even some in the freezer from when I ran out of jars. Usually my kitchen is a canning workshop by the end of August and it's been quite relaxing this year.

I noticed too, a canning book said one thing and my micromatic book another. I followed the pressure canner instructions. I was doing green beans. Gosh, I hope they are safe, I have a lot of quilts to make! I did corn today, but those pesky kernels are in the freezer now. I'll have to give this more thought the next time.

I don't know what the norm is but I pressure can my spaghetti sauce and salsa at 15# for 15 minutes, mostly quart jars. Haven't had any issues with them and some are still on the shelf after 2 yrs.

From what I have learned many of the electric pressure cookers on the market are not suitable for real canning. I follow the Instant Pot Facebook and there are many posts about it and here is something from the National Center for Home food Preservation. Unless you are using a "real" pressure cooker and not one of the newer versions.


http://nchfp.uga.edu/publications/nc...c_cookers.html

Pressure cookers are NOT pressure canners. Why take a chance in safety that can make someone very sick.
I have an InstaPot and use it only for cooking a hot meal.

Make sure you are using current methods, since the "low acid" tomatoes are different now than the tomatoes of the past, and mean that you need to add a form of acid before canning.

Great sources are Ball Canning recipes/website.

Extension Offices, different states have different websites, and they all have great info for all kinds of food preservation. (here is a free pdf for canning tomatoes: https://catalog.extension.oregonstate.edu/pnw300 direct link to pdf: https://catalog.extension.oregonstat...f/pnw300_0.pdf ) The pdf file has times and pressures based on elevation.

National Center for Home Food Preservation ( http://nchfp.uga.edu/ )

Taking classes, I learned that the PNW has a lot of naturally occurring C botulinum spores in the soil, so I'm pretty careful when it comes to canning.

The box says 22 quart pressure cooker and canner.

The instruction books that came with them have canning instructions.

I have two of them.

You can also check with your local Extension office. Ours offers classes/info on approved methods.

https://www.gopresto.com/recipes/canning/tomatoes.php

I compared my 40+ yo blue Book to the one I bought a couple years ago. Things have changed. Personally I would no longer trust my old "tried and true" recipes that family has handed down. I canned for years, grew up with it but rarely can now. While I wouldn't use my instant pot for canning I still have a 22qt and an 8qt stove top that I do use.

Have you had the gauge tested recently? I know the Extension Office here will test them. I've moved to using a weight (it will can at 11 psi or 15 psi only, depending on if you use one or both pieces) since the gauges are annoying to have to keep watching (as long as I can hear the weight rocking, I know the pressure is right at 11 psi).