I live in Italy - the Quattro Stagioni brand here has been around for more than 30 years, and it is considered the golden standard for in-house canning (other Bormioli glass products are well regarded, too); everyone I know who canned something in his or her life have been using them, and I've never heard of anybody saying anything but great stuff about them. It's rare that I go a whole month without eating something that is coming out of a Quattro Stagioni jar. The one-piece lids are indeed very handy, even if they are a bit pricey (but you probably already noticed that).
All of the Bormioli material (website) and instructions (I'm reading them now from the lid packaging) only mention canning with boiling (pasteurization to be precise), and I've only seen them used that way. This restricts the type of foods you can can (pun not intended) to highly-acidic ones: fruit conserves, tomato sauces, pickled vegetables, etc.
Of course, for maximum hygiene you should follow the instructions to the letter, and use a new cap every time. However, I've seen people successfully re-use caps for canning with less spoil-prone foods (e.g. pickled vegetables), but this is anedoctal and I don't think I can really suggest it.
The lid packaging also report a toll-free number “grandmother Amelia info” (not joking), but unfortunately it's late now as I write; I might call next Monday if I have time.
Happy canning!
Pressure cookers and pressure canners are the same thing; with the canners being larger, and often having a pressure dial. Both can reach the same pressures and therefore temperatures if designed and manufactured correctly
The pressure canners dial gauge is more accurate for adjusting for food types and altitude, as you can get exact numbers not just 10 psi and 15 psi as with typical weight regulated pressure cookers. But for low acid foods you need 15 psi anyway
Pressure preserving is done because of the higher temperatures reached. This saves time and energy, and some food react better to a short 250°F (120°C) cook that an long 210°F (100°C) cook
Pressure preserving high acid food is worth doing as long as the food does not deteriorate quicker due to the high temperature (some soft fruits will)
For preserving low acid foods you need a known good pressure cooker that can reach 15 psi (103 Pa) and therefore 250°F (120°C)
With a commercially published recipe that has been acid level tested, you will have a published time that will be safe. For a home-made recipe you have to take the worst case scenario for the acid level of the main content, and cook for that. Your local government health department will most likely publish tables for this that you should be using. Remember to use altitude adjustments for timings too
Just relying on adding a teaspoon of vinegar or lemon juice per jar is not a safe and scientific method for raising the acid level, though many people do it, and have not come to any trouble with it?
You pressure cooker should come with a manual that confirms what it can or cannot do. Download a new copy if this has been lost
Also see What kinds of pressure cookers are there, and what are they good for?
Best Answer
Because meat stock is low-acid you're going to need to use a pressure canner. Follow the pressure and times indicated in a reliable guide such as this one from the Montana State Extension
You won't need to add acid to make it safe.(edit)