James Silverton wrote:
> On 4/4/2011 12:24 PM, Kent wrote:
>>> 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,
>
> The Wikipedia article seems pretty reliable especially on the nature of
> "double-acting" baking powder, something I was never very clear about.
> The article also gives more history than you might ever want to know :-)

Thanks to you too. I actually have some old booklets on the
topic, as well as polemics and claims about the superiority of
various baking powders.

--
Jean B.