That will let me know just how airtight that sucker really is.
If it's 25 gallon, I don't think it's airtight at all.
Thank you Scott, I will start hitting up the bakeries.
One other advantage of the bakery containers is that, instead of one huge container that exposes all the flour when you open it, you can break up the bag into multiple containers. If I aggressively vibrate the container to get the flour to settle, I can squeeze a 50# bag into two 4.25 gallon covered buckets, but, in your case, you might want to go with 3 containers.
Btw, every supermarket department uses these plastic buckets. I think the best department to ask is the bakery, as they go through the most of them (icing, glazes, etc.) and the ingredients don't have an odor that permeates the plastic like the pickles at the deli or the seafood buckets. When you ask for your bucket, offer to wash it yourself, since the buckets waiting to be recycled will all be covered with some kind of sweet goo- and they'll be more inclined to give you one if they don't have to wash it first.