[...] can find the recipe on their web site too – no need to buy some yogurt (just in case you are making your own), even though their yogurt is the best I’ve found this side of the [...]

I’m using Mason jars because they are convenient. They are glass, so I can run them through my dish washer’s “sanitize” cycle before, the lids screw on, so it’s easy to open them and close them again, and
it’s not plastic, so I don’t have to worry about softeners and other nasty stuff in my yogurt.

I keep them in the fridge (just like any other yogurt), and I usually make enough for four weeks. So, I know that it keeps at least for four weeks. I would not go much past that, but I really don’t have any
experience.

Does that answer your questions?

What I am wondering is how long the shelf life is and are you keeping it in a cold dry space, refrigerated or what. Can it be kept outside the fridge? For how long, etc.?