@hightor,
baking soda for bakeries usually includes a bag of a drier agent. household sizes , unless theyre the "Amish Family size" are in muh smallr boxes and are used up within a yar.Baking soda will suck up vverything around it espcially water. Most people kep an open box in the frige to deodorize .
I shoulda said,Anti-"caking" agents. According to the web, these are usually dusted on to the sugar, flour, baking powder(soda) Hw soune lik he got it as a raw product