Sift flour and put in a dry covered Dutch oven or an iron skillet on a very low heat. Stir with a wooden spoon occasionally until it is a rich golden brown (approximately the color of a brown paper bag). Cool and store in a sealed air tight container. Can be kept on a shelf in the cabinet (but it is preferable to store in refrigerator).
When ready to use heat oil and put in dry roux and mix well and continue cooking stew, gumbos or whatever requires a roux.
More can be added if the gravy is not thick enough also good to add to thicken any gravy.