Our preferences for baking powders are ones that are made with an all-phosphate product containing calcium acid phosphate and non-GMO cornstarch. Baking powders containing sodium aluminum sulfate (SAS), to aid in releasing more carbon dioxide during the baking stage, generally have a bitter after taste, especially noticeable when added to pie dough. Recently, Rumford released a new baking powder, Rumford Reduced Sodium Baking Powder, which contains 52% less sodium than leading brands and no aluminum. Rumford informed us that this new product activates mostly during the heating/baking phase. We were curious to test this new baking powder since timing of activation has a great impact on baked goods, especially muffins and cupcakes. Letting the cupcakes rest before baking gives the cupcakes more rounded tops because if more of the baking powder activates in the early stage from the liquid in the batter there is less to disrupt the cell structure, during baking, needed to collapse the crumb to form a flatter top. My White Velvet Butter Cake recipe served as our test recipe, since it is an egg white based butter cake and has a somewhat neutral flavor, which enables us to perceive differences during tasting more easily. Since there can be a relatively long time frame to fill over a dozen cupcake liners, during which the baking powder will have begun to activate, we wanted to see if the new baking powder, which reacts more in the baking stage, would give us a wider window of time to fill the cupcakes and result in more uniformly shaped cupcakes. We made two batches of cupcakes with each baking powder serving as the leavening for each batch. Once we filled the cupcake liners, we also let some of the cupcakes rest 20 minutes, and others 30 minutes before baking them. We baked all of the cupcakes for the same amount of time.
ORIGINAL RUMFORD ON THE LEFT, LOW SODIUM RUMFORD ON THE RIGHT
The test card shows the height in inches, then the width in inches. The cupcake on the left, made with the original Rumford baking powder, had the batter stand for 20 minutes after filling the muffin cups and before baking as did the one on the far right, made with the new Low Sodium Rumford baking powder. (It is both flatter and wider.) The middle cupcake, which is very similar to the original Rumford, but made with the low sodium baking powder, stood for 30 minutes before baking. The results indicate that the new Rumford baking powder is more effective in preventing doming for up to 20 minutes of standing time but not longer. However, when we gave them a taste test we found major differences.
The original Rumford cupcakes had a more pronounced flavor and texture. The sodium reduced Rumford ones were milder in flavor and fluffier. We preferred the original Rumford for flavor and texture. People are always asking either how to get more rounded cupcakes or flatter ones to hold more frosting. One of the major problems is that if making 12 or more cupcakes, by the time the last few cupcake liners are ready to be filled, the batter has been sitting in the bowl for at least 10 if not more minutes, resulting in more doming in the baked cupcakes. The longer the batter stands in the bowl before dispensing, the more the loss of leavening action during filling the liners. Once the batter is dispensed into the muffin liners this action slows down but is still taking place. So when the muffins are set in the oven, there is less leavening available to burst through the air bubbles in the batter to flatten the crumb during this heating phase.
Did you know that different brands of baking powder have different compositions, reactions, and results in the finished product? If you'd like to know why, continue reading!
Baking powder is a chemical leavener that is used primarily in cake baking to enlarge the air bubbles in the batter, which gives volume and tenderness to the cake crumb. In Europe, most cakes are leavened with beaten egg white or whole eggs whereas in North America, most cakes use baking powder, baking soda, or a combination of the two. Baking powders are mixtures of dry acid or acid salt and baking soda, with starch or flour added to stabilize and standardize the mixtures.
Most baking powders are "double acting," meaning that they will react or liberate carbon dioxide when they come in contact with moisture during mixing of the batter and again when exposed to heat during baking. (A "Single acting" leavener, such as baking soda alone, reacts fully when it comes in contact with moisture.)
We also, tested the two baking powders by activating 1/2 teaspoon of each in custard cups with hot water. Within less than a minute the original Rumford had activated, fizzing furiously to completely dissipate. The reduced sodium Rumford only activated partially with dry, non-activated powder nestled on top of the foamy activated powder (even after 10 minutes). Doing this hot water test is good method for verifying that your baking powder is still activated.
We recommend that you always mark the date upon opening a can of baking powder and store it airtight to avoid humidity. Baking powder can lose a substantial amount of its strength after about a year.
We have also tested Argo's baking powder, which also activates more during the heating phase. We tested it against our baking powder of choice, Rumford's original Aluminum-Free Baking Powder. We found it especially effective in cakes baked in fluted tube pans as we could use the same amount of baking powder, but the Argo resulted in a less domed top which, when inverted, sat flatter on the plate. (To get similar results with the Rumford would require such a minute amount of extra baking powder it would be hard to measure accurately.) When using the Argo in a layer cake, however, it needed to be decreased to keep the cake from dipping.
Here are the ingredients listed for each baking powder: Rumford Original Aluminum-Free (red background can) Monocalcium Phosphate, Sodium Bicarbonate, Non-GMO Cornstarch Rumford Reduced Sodium Aluminum-Free (silver background can) Monocalcium Phosphate, Calcium acid Phosphate, Sodium Bicarbonate, Non-GMO Cornstarch, Potassium Bicarbonate Argo Aluminum-Free Sodium Acid Pyrophosphate, Sodium Bicarbonate, Corn Starch And Monocalcium Phosphate. The White Velvet Butter Cake recipe is in The Cake Bible and Rose's Heavenly Cakes.