-- and it not be affected? Like say, baking soda/powder, flower, salt, spices etc..? I Kind of went ahead and did it before I asked (D'oh!), but I mixed my dry ingredients to be used tomorrow (most likely in the morning). They are all saran wrapped.
How long will it be ok for?
What activates the baking soda/powder? If i remember correctly yeast is activated by sugar.. Though i dont know if baking soda/powder works the same way..
It'll be okay, the baking soda/powder are activated when it is mixed with the wet ingredients. So you can even mix together just the dry ingredients days ahead and it would be fine. I've done it numerous times without any problems.
It is as strong as its weakest link. For example, if the leavening expires in 6 months, that's it.
The only problem with your application is if some of the dry are mixed separately with other ingredients before full incorporation.