Baking Soda vs. Baking Powder: Stop Mixing Them Up

They sit next to each other in the cabinet, they are both white powders, and the names are one word apart. So it is no surprise that baking soda and baking powder are the two ingredients home bakers mix up most. They are not interchangeable, and grabbing the wrong one is one of the most common reasons a batch of biscuits or muffins comes out flat, bitter or strangely dark.

Before Either One Existed

For most of baking history, if you wanted something to rise, you used yeast, and you waited. Home bakers made their own yeast by fermenting fruit, vegetables or grain, and a rise could take 12 hours or more, often closer to a full day.

The first shortcut in America was pearlash, a potassium carbonate made from lye and wood ashes. It shows up in the very first American cookbook, Amelia Simmons's American Cookery, published in 1796. It worked, but it was hard to make, caustic and often smelly.

Baking Soda Hits the Shelf

In 1846, two brothers in law, Dr. Austin Church and John Dwight, began preparing bicarbonate of soda for sale, packing it by hand into paper bags in Dwight's kitchen. That little operation became Church & Dwight, the company behind Arm & Hammer. Back then it was often sold as saleratus, Latin for "aerated salt."

Bakers paired it with sour milk to supply the acid. That worked, but sour milk is not exactly consistent, so neither were the biscuits.

The First Baking Powder

In the 1840s, an English chemist named Alfred Bird combined baking soda with cream of tartar, an acid, keeping the two apart until it was time to bake. The catch: cream of tartar (a natural byproduct of wine making) was an expensive import, out of reach for a lot of American kitchens.

The fix came from a Harvard chemistry professor, Eben Norton Horsford. On April 26, 1856, he patented a cheaper acid, calcium acid phosphate, originally made from boiled animal bones, and mixed it with baking soda and cornstarch in a single container. The cornstarch kept everything dry until it met liquid. That was the first modern baking powder, and the same idea is in the can in your cabinet today. His powder was later sold as Rumford, and by the late 1880s the phosphate came out of mines instead of bones.

The Baking Powder Wars

Once baking powder caught on, the companies making it went to war. Royal Baking Powder, built on cream of tartar, sold itself on purity and attacked the cheaper powders made with alum. In 1899, Royal bribed the Missouri legislature to ban alum baking powders. According to Linda Civitello, author of Baking Powder Wars, the fight lasted six years, involved millions of dollars in bribes and sent dozens of people to jail. All over a can of leavening.

What It Changed

Baking soda and baking powder turned an overnight wait into a few minutes in the oven. That is why quick breads are called quick, and why biscuits, muffins, scones and pancakes became everyday food instead of a special project.

Here is the difference, in plain English.

Baking Soda Needs a Partner

Baking soda is sodium bicarbonate, a base. On its own it does nothing for your batter. It only goes to work when it meets an acid, like buttermilk, yogurt, sour cream, brown sugar, molasses, honey, natural cocoa or lemon juice. The moment the two meet in a wet batter, they make carbon dioxide bubbles, and those bubbles are your rise. That reaction starts right away, so a batter made with only baking soda wants to go into the oven soon after it is mixed.

Baking soda is strong. A little goes a long way, and too much leaves a soapy, metallic taste and an overly dark color. Because it is alkaline, it also helps with browning, which is why it shows up in recipes where a deep golden color matters.

Baking Powder Brings Its Own Acid

Baking powder is baking soda with the acid already mixed in, plus a little starch to keep it dry in the can. All it needs is liquid. Most baking powder on the shelf is double acting: it releases some bubbles when it gets wet, and a second round when it hits the heat of the oven. That second lift makes it much more forgiving, and it is why a scone dough made with baking powder can wait a few minutes on the bench without losing its rise.

Why Some Recipes Use Both

If a recipe calls for both, there is a reason. The baking soda handles the acid in the recipe and adds browning, and the baking powder makes sure there is enough lift. Pull one out and you will notice.

Can You Swap Them?

Not one for one. Baking soda is several times stronger than baking powder, and without an acid in the recipe it will not rise at all and will taste off. If you are out of one, the safer move is to find a recipe written for what you have.

Is Yours Still Good?

Both lose strength sitting in the cabinet. To test baking soda, drop a little into some vinegar or lemon juice; it should fizz hard right away. To test baking powder, stir a little into hot water; it should bubble. No fizz, no rise. Keep both sealed tight in a cool, dry spot, and move baking soda out of its cardboard box into an airtight container.

Want to See It in Action?

Leavening is the whole game with scones and biscuits, and that is exactly what we cover in our Breakfast Pastries class: Scones and Biscuits, this Sunday, November 8, from 2 to 5 PM at the bakery. You will mix, shape and bake your own and take them home. Tickets close Friday.

Chef Keegan and The Lakehouse Bakery Team