Found this about homemade peanut butter.
"Store it in the refrigerator until you use it. It should keep for a month or two. You can also freeze it. It will keep indefinitely in the freezer. In both cases, you may need to stir the peanut butter to mix the oils back in (the oil tends to separate over time). And no, you cannot "can" the peanut butter - it is too low acid to safely can with home equipment."