Flour can totally go rancid (and more easily than I thought). I always freeze it because once a whole grain is ground up or milled in any way, it is exposed and starts to break down. Look at this as a good thing because it's indicative of a live food with more usable nutrients.
I've used "King Arthur Flour" which is found in most grocery stores and the kind is called "Unbleached White Whole Wheat Flour." It is a lighter milder 100% whole wheat, and I actually heard about it on sirus xm Martha Stewart radio one day last November. Ha! I believe that the "King Arthur" namebrand is a more trustworthy source of fresh whole grain flour than most, but it's also important how the store owners keep it (needs cool temperatures to be fresh, always look at the date). Look at the King Arthur website for some great recipes too!
I was told by a natural foods doctor (he's also a medical doctor) that most whole grain flours are rancid just sitting on the shelves in the stores because of being stored at warm temperatures. Many grain mills crank out a tremendous amount of heat themselves and damage the quality and nutrition of the flour. The problem is that they can taste fine even when they are rancid. So it's hard to tell.
Grinding your own flour... which I have found is much easier than I could have imagined... is the way to guarantee freshness. I have a Vitamix and that thing can do it lickity-split. I just buy a bag of the dry whole wheat "berries" (as they're called) from the health food store. I like the kind of wheat called "organic golden hard white wheat." And I pour about 3 cups at a time into my Vitamix and run it on high for about 1 minute. Done. It's the freshest possible whole wheat flour with all the nutrients in tact. I can taste the difference and it's really good. I freeze whatever I don't use. And whenever I use it, I always make sure that the flour has a chance to "soak" overnight in the batter or dough before baking. This makes a big difference too.
There is also a company called "Frankferd Farms Foods" who makes wonderful whole grain flours and I called them to find out if they refrigerate them right after grinding... and they said that they usually ship them out right away, but if the bags of flour are going to stay on the premise for more than a day or two, then they always refrigerate. If I use white flour, I like Frankferd Farms "Unbleached White Flour with the germ added back in." The health food store I go to (Miller's Natural Foods) always refrigerates all their whole grains and whole flours. http://www.frankferd.com/
Today, I went to a new little organic grocery store on King St. in Lancaster (across from McDonald's) called "Expressly Local." It's great! And they carry "Daisy Organic Flour", a locally milled organic flour. One of the store owners told me that the difference between pastry flour and bread flour is that pastry flour is very very fine while bread flour is a little more course so that it can keep it's texture and shape in bread. She said that "All Purpose" flour is somewhere in between in the two texture. I learned something new today!
Tomorrow, I'm going to Gap to attend the next "Ladie's Day" health food meeting at 10am. Can't wait!