I make a homemade rub that we just love for prime rib like for on the 35 day Drybag aged one that is for supper tomorrow night. I make it in small batches, but there is always a goodly bit left over so I save it in a tightly sealed glass spice jar from Penzkys. Then when I make a new batch I mix in the leftover which always is just a tad clumpy by then. I have been thinking that maybe I should add some anti-clumping agent to prevent that. Would common corn starch work? OTOH since I assume the clumping comes from the presence of moisture would merely adding some dry white rice to the stored rub do the trick and not add any taste?
L, M, S, Mini