On Fri, 24 Dec 2010 15:25:41 -0500, blake murphy
> wrote:

>On Thu, 23 Dec 2010 15:43:52 -0600, Terry wrote:
>

>> It shouldn't make any difference whether the baking soda is two years
>> old or (literally) two hundred. Sodium bicarbonate, like table salt,
>> is a stable inorganic substance at room temperature. As long as it's
>> uncontaminated it should be fine.
>
>o.k., thanks. maybe i'm thinking of the diminished capacity of old baking
>powder.

Yes, baking powder is a mixture of baking soda and one or more solid
acids. The base and acid will react slowly over time, in the presence
of moisture. I've found that baking powder that is a year old still
seems to work ok, but I throw it out anyway. A dollar a year, it's
cheap enough. :-)
--
Best -- Terry