[CottonBall]

Cream of tartar is a by-product of the wine-making industry and is derived from tartaric acid. As an acid, it is the counterpart to baking soda and when the two are combined they create a chemical reaction which produces carbon dioxide. Most recipes that call for cream of tartar also call for baking soda.

In my quest to gather shelf-stable supplies to use when/if TSHTF, the 'recipe' for baking powder (which has an expiration date) is a combination of baking soda, cream of tartar, and cornstarch. All of which don't have an expiration date if packaged with oxygen absorbers in a non-permeable container.

I believe it because I've read it often enough on survival sites - but have wondered why packing baking powder the same way wouldn't last for years as well...any ideas?

[nw_arizona_granny]

I keep my baking powder in the refrigerator, it lasts past the exp. date there.

Keep the yeast frozen and it is good long past its exp. date.

If it is way past, then I add a little more.