Using the recipe in the link below, what would be the shelf life?
Anyway to prolong the shelf life?
That site is not generally considered the best source for canning instructions as each recipe has to be individually evaluated.
In this particular case the biggest issue is that it calls for canned or already processed applesauce as the main ingredients. Re-canning is not generally recommended.
If you use commercially canned it will already have the needed citric acid added. Use your own canned and it may not so pH problems could arise. But the recipe doesn't call for the recommended added acid - citric acid or bottled lemon juice.
And there is some dispute over using a crockpot to cook it as it doesn't get hot enough to kill all bacteria.
So shelf life, as the recipe says may be 18 months or may be less. Adding the recommended acid would help. But it is mold that is the issue and that should be obvious when the jar is opened.
If you want a longer shelf life then use any of the tested and approved recipe available and include the recommended added acid.
I used fresh apples picked from my own tree. I also cooked apples on the stove top with a touch of lemon juice.
Ok then I guess I don't understand your question if you didn't use the instructions you linked.
Are you asking what is the shelf life of apple butter made the normal way with one of the approved recipes such as the Ball books or NCHFP? If so then 4-5 years average although it will darken in appearance.
To clarify.. I cooked on stove top and then transferred to crock pot. I used the water bath method.