Baking soda verse baking powder

[2008plove]

I have a question regarding the two. Is there a difference when using for baking purposes?

[Zeldaz]

Baking powder contains baking soda (base) plus an acidic element like cream of tartar; it is activated by liquids as well as by heat. Baking soda must be mixed with an acid (buttermilk, lemon juice, etc.) to release its CO2 gas to leaven a baked product.

[DrGaellon]

Oh yes, they are NOT interchangable.

Baking soda is sodium bicaarbonate. It is a base; when mixed with an acid, it liberates carbon dioxide, which is what makes your baked good rise.

Baking powder is sodium bicarbonate plus a dry acid; when mixed with water, it also liberates carbon dioxide. Double-acting baking powder has two acids - one works at room temperature, but the other doesn't work until it is heated, so you get some additional carbon dioxide formation in the oven, giving you additional lift.

You can replace baking powder with baking soda (use 1/4 the amount) *IF* you add some acid, either to the liquids or in the form of cream of tartar (use half as much cream of tartar as the original amount of baking powder). Doing this, once you mix the wet and dry, you must get it into the oven (or the pan) quickly before the carbon dioxide escapes and your item fails to rise.

[2008plove]

Thanks. I never understood why my cake would not rise even when I would add baking powder. I thought it was the wrong ingredient. So I know to use an acidic compound with it.

[Zeldaz]

No, baking powder has acid built into it, it's baking soda that requires added acid. How old is your baking powder? It does go "bad" and lose its leavening power. http://wiki.answers.com/Q/Can_you_use_old_baking_powder

[DrGaellon]

Yes, baking powder is only good for 6 months to a year. Add 1/4 tsp to 2 tbsp of very hot water; if it doesn't start to bubble, get a new can.

[Chicagoland Chef du Jour]

When using baking SODA, it's important that it be fresh as well.

Test a little of it in a bit of vinegar. If it foams up, it should still work in baking.

[Peter Bergerson]

Baking soda doesn't age the same way as baking powder does. They both will absorb moisture and odors from the air, but that's where the similarity ends. The absorbed moisture will activate baking powder while it will only cause baking soda to cake together and/or taste funny.

Old baking soda that's no longer suitable for baking can still be used for cleaning and deodorizing, but old baking powder is useless.