Because of its high oil content and low moisture, peanut butter has a very long shelf life. For the most part, therefore, you don't need to freeze it to keep it from spoiling. However, there are some times when you might want to put a jar of peanut butter in the freezer. When you do, it will freeze solid without losing any of its flavor or texture.
Peanut butter has a long shelf life even at room temperature. An unopened container of peanut better can stay in the pantry for up to a year or more, and an opened jar should still be good for two to three months. Gradually, oils in the peanut butter will begin to break down, turning rancid and spoiling its flavor. The peanut butter isn't actually unsafe, but it won't be very appetizing. To extend the shelf life of a container of peanut butter, put it in the refrigerator -- at 40 degrees Fahrenheit or lower, it will last up to nine months.
Since it's not hard to use up a jar of peanut butter in six to nine months, the need to freeze a container doesn't often come up. If it does, though, peanut butter should freeze without any problems. Uses for frozen peanut butter include:
Frozen peanut butter and jelly sandwiches. You can freeze an entire sandwich, transfer it to the refrigerator to thaw the night before you intend to eat it, then put it in a lunch box in the morning. Keep sandwiches in a heavy-duty freezer bag; the peanut butter shouldn't suffer from being frozen, but the bread can.
Alternatively, freeze a thin layer of peanut butter in plastic wrap and put it between slices of fresh bread for a quick sandwich.
Frozen dollops of peanut butter are a convenient treat for humans as well as for dogs. A mixture of unsweetened peanut butter and mashed banana frozen into a cube or dollop makes a cooling snack that will keep a dog occupied on a hot day. For added play value, freeze the peanut butter in a mold made from a rubber bone.