not suitable for longer-term storage

The Church of Jesus Christ of Latter-day Saints has indicated that some grains "may not be suitable for longer-term storage." They've included these three grains in their list because of "rancidity" concerns. 1

Pearled Barley
Whole barley has to be dehulled for human consumption. Once it has been processed, it can no longer be sprouted.2 When ground into flour, barley does NOT make good bread.7 Hulled barley still contains a significant amount of oils and will become rancid fairly quickly. It can be stored in the fridge to lengthen the shelf life. Pot barley is a dehulled barley which has been polished to remove additional oils. Pearled barley has been polished four to six times for an even longer shelf life. Pearled barley is considered a "soft" grain and consequently only has a shelf-life of around eight years.3 The Church of Jesus Christ of Latter-day Saints does not recommend pearled barley for longer-term storage because of concerns about rancidity. 1 Utah State University labeled it an "oily grain." 4

Whole Wheat Flour
Once the wheat kernel has been milled, the oil content of the wheat is exposed to the air and becomes rancid very quickly. The shelf-life of wheat flour can be extended up to 12 months by storing it in the freezer. 3, 6

Brown Rice
Like wheat flour, brown rice has a high amount of fatty acids which become rancid as they oxidize. Brown rice can be stored for about 6 months on the shelf. It will store much longer if kept in the refrigerator. 5


All of these items can be successfully stored as part of a regularly rotated three-month supply.



Sources:
1 - The Church of Jesus Christ of Latter-day Saints
2 - Walton Feed
3 - Walton Feed - Storage Life
4 - Utah State University Extension
5 - Riceland
6 - University of Nebraska Extension
7 - Selecting & Buying Grains (Alan T. Hagan)