I ordered this product, 4 pack in March and got a best by December 2013 on the bottom. I hope that's not really a problem, because I don't think I will be making that much of it that I would be able to use it up. You only use 2 tsp for 2 cups flour. So it would take a long time to use it up!
I really wanted an alternative to cornstarch based baking powder beacuse of GMOs in corn. So this was a good find.
I just made 1 inch diameter biscuits using 12 oz 100% whole wheat flour, 2 tsp of this, 200 mL of filtered water. In the oven at 350F after 13.5 minutes they rose 10-20%. I guess if I want more rising I add more next time. I used 4 tsp of the baking powder on another occasion and nothing rose at all.