No, those tiny little bottles at the supermarket sure won't work. We have a health food store here which sells bulk herbs and spices. They have cream of tartar there. If you have a similar store, you could check there. If not, try online suppliers such as herbalcom.com. It's $5.50 a pound there, but they do have a shipping/handling charge of $5.25 per order, so unless you're ordering other things, or more than 1 lb, it may not be worth it.