Abstract: Disclosed are high temperature, high pressure, short residence time methods for heat treating whole cereal grains which upon milling form raw whole grain flours which exhibit enhanced storage stability. The heat treatment step involves introducing the cereal grain into a zone of high pressure and temperature. Conventional continuous cereal puffing gun apparatus are useful to practice the process. Thereafter, the whole grain is introduced to a second zone of lower pressure but wherein the pressure differential is insufficient to cause puffing. After cooling without further drying, the treated grains can be milled to form the raw whole grain flours. The whole grain flours are especially useful in the preparation of whole grain cereal products such as whole grain R-T-E corn flakes.