Oat bran, which is the exterior of the oat grain, is separated from the rest of the grain when it is refined, or processed. The bran contains fiber and protein. It also contains fat, which can turn rancid with exposure to air or light. A dark, cool place is the best site for oat bran storage, and the darkest, coolest place in your kitchen is the freezer. The oat bran will remain fresh there.
Put the oat bran into a resealable, airtight bag. Push out the excess air, and seal. This bag will keep the bran protected from oxygen and moisture.
Place the bag into an airtight container, and seal it. The container will protect the oat bran from picking up freezer odors.
Freeze the container for up to one year. Use the oat bran straight from the freezer when needed.