Storing pre-mixed dry ingredients for banana bread?
It's been a while since I've been around here, but I know all of you are extremely wise when it comes to kitchen knowledge so I'm wondering if you wouldn't mind helping me out with something. My boyfriend has a great banana bread recipe that everyone loves - he gets so many requests for it that he ends up making banana bread on a pretty regular basis. He was wondering if he could pre-mix the dry ingredients and store them in large quantities so he'd only have to add wet ingredients later. The things included in this are baking powder, baking soda, flour, and salt. He wanted to know if he could mix the sugar in as well. Would there be any negative effect if he mixed these ingredients ahead of time and stored them in airtight canisters?
Thanks to anyone who can help!