The only aromas associated with clean, whole-wheat flour, bought as a ready milled product, or milled at home are 1) A grainy aroma which is normal. 2) A rancid aroma, slightly sharp and heavy. This is not a desirable aroma as it is due to rancidity of the wheat/flour. Whole-wheat flour will go rancid within a month of milling if not correctly stored (frozen or refrigerated) due to the germ oil being present in the whole-wheat flour. I would candider any other aromas to be "foreign".
One of the foreign aromas that we pickup occasionally is a musty aroma (think old, wet/damp newspapers), this can be caused by improper storage of the flour or wheat prior to milling/grinding. In this case the wheat/flour was stored in a damp location and it may have begun to mold (reason to discard). In some baked products made with whole-wheat flour we find a fruity/melon like aroma. This aroma is due to "rope" spores. Rope is a spore forming bacteria that is not destroyed during the baking process, and is in fact activated in the oven. It manifests itself by forming the characteristic aroma. Rope is soil borne, so it tends to be more prevalent in whole-wheat items, but it can still affect products made with regular white flours too. Rope is not dangerous, but the aroma is not desirable, so any products found with this aroma should be immediately discarded. In a bakery setting the rope infection can be transferred to other parts of the bakery making it extremely difficult to get rid of. FYI: Vinegar will kill rope spores on contact. So if you ever find that you have this pesty little number as a visitor to your kitchen, just wipe everything down with a a sponge or towel soaked in regular, household vinegar.
Tom Lehmann/The Dough Doctor