Flour (Fallout 3)

Flour can be used as Rock-It Launcher ammunition. However, its more important use is as an ingredient in Mississippi Quantum Pie. It is not listed as a food item, but as a miscellaneous item.

There is only one guaranteed sample of flour out in the world. It can be found in a diner roughly north of the Nuka-Cola Plant and west of the Red Racer Factory. In addition, several vendors will sell flour:
 * Gary Staley and Seagrave Holmes in Rivet City
 * Lydia Montenegro in Tenpenny Tower
 * Moira Brown in Megaton
 * Knick Knack in Little Lamplight
 * Michael Masters in Warrington Station/Tenpenny Tower
 * Karl in Meresti Metro Station
 * Crazy Wolfgang(after you invest in his caravan)

If flour is needed, it is worth checking the inventory of any other vendor or scavenger as well, as there is a small chance it will be available for sale from these individuals.

It can also be found in the kind of random loot found in schools and kitchens.

The venders sell Flour more sporadically than static, so be sure to come back on other days to check their inventory. Also, if you kill one of them, chances are you will be unable to find it lying about at their location. You will have to get it directly from Gary Staley, Moira Brown, Lydia Montenegro, Michael Masters, Karl, and Knick Knack. If you off one of them, you won't find it in the supply crates or anywhere.

Also, if for some reason you didn't gain access to Meresti Metro Station, you will have to pick the lock or kill the guard. Doing either of these and not leaving will only result in everybody trying to murder you, including Karl.