>I have been baking muffins recently. I opened a can of baking powder,
>which was not past its expiration date or even close to it. I realized
>last night that it must, nonetheless, be old, because the muffins just are
>not rising much. Sooo, I am wondering:
>
> 1) Does BP age in an unopened can? I note that the cans are not all metal
> now, so I imagine the cardboard would not offer the same level of
> protection.
>
> 2. Do all double-acting BPs have the same leavening power? The one I have
> open is Rumford, but I have always used Calumet in the past. For some odd
> reason, Calumet is almost impossible to find here now.
>
> Thanks,
>
> Jean B.
>
>
The chemical makeup of baking powder is: baking soda plus cream of tartar
plus cornstarch.... or:

I thought there was a clear answer to this; apparently there is not. I'd
contact the mfg. They're generally more helpful than you would imagine about
a question like this. I recently had a long very insightful conversation
from the mfg. of Ziploc bags regarding their heat sensitivity.

Banking soda=
NaHCO3. baking soda
Cream of tartar KHC4H4O6.
NaHCO3 + KHC4H4O6 ----> KNaC4H4O6 + H2O + CO2
Some baking powders contain sodium aluminum sulfate: NaAl(SO4)2. The
reaction there is:
NaAl(SO4)2 + 3 NaHCO3 ----> Al(OH)3 + 2 Na2SO4 + 3 CO2
Read mo What is the chemical composition of baking powder | Answerbag
http://www.answerbag.com/q_view/411545#ixzz1IZWR6tON
Baking powder is baking soda plus cream of tartar plus cornstarch....


Good Luck, let us know,

Kent