I bring the cider to a boil and simmer the spices for 15 minutes. Immediately after, I pour the cider into canning Mason glass jars with the lids that have the button. How long should I expect the cider to be good for unopened?
1Your title says sealed, but if you're not processing it after filling, I don't think you can really guarantee that they're sealed. Are you willing to perhaps change your process if your goal is to get it to last?– Cascabel ♦Dec 20, 2014 at 6:52
Thanks. I'm definitely open to that. I would be curious what the longevity would be for both processes.– Kyle HayesDec 20, 2014 at 23:35
Assuming you follow the usual procedere of cleaning and boiling ("sterilizing"1) the jars, filling the hot cider in hot jars and closing immediately, you should be fine for a few weeks. Or not, there is always a slight risk of the jars not sealing properly and your cider not being acidic enough.
Processing the jars as you would for other canning and repeating the processing after a day or two should get you on the super-safe side (including eliminating the very, very slim botulism risk from your spices).
This is probably overkill, even a standard waterbath canning should leave you with a cider that stays good for a year or more.
Just remove the rings after the jars have cooled well, so that any faulty seal becomes obvious right away.