Thank you for your question. After the jar has been opened a few
months it should be refrigerated in order to retain flavor and prevent
it from becoming rancid.
If peanut butter is refrigerated it should come to room temperature before serving.
According to the Jif.com website - Do I need to refrigerate Jif?
"In the first three months after opening, Jif doesn't require
refrigeration. If your family doesn't gobble Jif up by then, you may
want to refrigerate the peanut butter to help prevent flavor loss."
UNIVERSITY OF NEBRASKA COOPERATIVE EXTENSION SERVICE
"Peanut butter should be stored away from air, heat and light. It can
become rancid if stored improperly or for too long. Before opening,
peanut butter can be stored for about 9 months without refrigeration.
After peanut butter has been opened, it should be kept in the
refrigerator. Remove it from the refrigerator a short time before
using to allow it to soften. Peanut butter can be kept in the
refrigerator after opening for about 2 months."
Cupboard Approxiamte Storage Times - Peanut butter
unopened: Storage time 6-9 months - Refrigeration not needed
opened: Storage time 2-3 months - Keeps longer if refrigerated, use
at room temperature
Peanut butter once opened should be stored for no longer than 2 months
in the cupboard. Extra peanut butter should be packaged and stored in
The About.com site states the following on Peanut Butter Storage
"Commercial varieties require no refrigeration, can be kept up to six
months after opening, and unopened jars can be stored up to one year
in a cool, dark location. Peanut butter is not a good candidate for
The Cook's Thesarsus
Most shoppers turn instead to commercial peanut butters, which don't
need to be refrigerated (after opening) and don't separate.