Hello bakers, I've found some banana bread recipes which use baking powder as their only leavening, and some banana bread recipes which only use baking soda. Are bananas acidic? These are not recipes using sour cream or yogurt or any other acidic ingredients. So I'm confused about the use of baking soda rather than baking powder. Thanks all...
Acidity versus alkaline may be a consideration when browning is a factor. An alkaline batter promotes browning, so baking soda may be used exclusively or with baking powder when deeper browning is desired.
The difference in activation between baking soda and baking powder is probably the more important consideration.
Baking soda is not double acting. So there is just a single burst of CO2 activity. Baking soda leavened batters/doughs must be baked immediately. As a single acting leavening agent, it is normally used in baked goods that do not require a long bake and/or little rise like cookies and biscuits.
Baking powder is double acting.
Because baking powder is double acting and acidic, it is the preferred leavening when a baked good requires a longer baking time, more rise, less browning.
Double-acting means the leavening will activate when it comes in contact with liquid, go dormant, then activate a second time when it reaches a certain temperature.
The first activation happens when the acid comes in contact with moisture. So baking powder like baking soda first activates in the mixing process.
Baking powder’s second activation happens when the acid reaches 140°F. The sustained CO2 activity is designed to produce a higher rise; more even and airier crumb. It has less chance of collapse when cooling as the second activation occurs at a temperature close to that of starch gelatinization and protein denaturation. The starch gelatinization and protein denaturation form a matrix that traps and expands with the gas bubbles; then sets.
Baking soda does not provide a second burst of leavening activity.
These brands contain two acids:
Argo
monocalcium phosphate and sodium acid pyrophosphate
Clabber Girl
monocalcium phosphate and anhydrous sodium aluminum sulfate
Sometimes Sodium pyrophosphate (aka Disodium pyrophosphate) is used.
Rumsford contains just one acid, monocalcium phosphate. It is often mistaken for a single-acting baking powder, but it is a double-acting baking powder.
When the monocalcium phosphate comes in contact with liquid at room temperature, two-thirds of the CO2 will release within two minutes of mixing. It will then go dormant because dicalcium phosphate is a byproduct of mixing. When it is heated to 140°F (60°C) it will reactivate.
Just an aside, common ingredients like brown sugar, honey, cocoa, chocolate, molasses can all activate baking soda.
