Baking Powder and Bicarbonate of Soda in Pancakes: What Each One Does

The short answer: baking powder and bicarbonate of soda (baking soda in the US) both make pancakes rise. They release carbon dioxide gas in the wet batter and in the heat of the pan, and the bubbles lift the batter into a thick, fluffy pancake. Baking powder carries its own acid, so it works in a plain milk batter. Bicarbonate of soda needs an acid in the recipe, such as buttermilk, yoghurt or lemon juice, and tastes soapy without one. Thin British pancakes and crêpes need neither.

The two get mixed up constantly, partly because recipes use different names on either side of the Atlantic and partly because they look identical in the cupboard. This guide explains what each does, which one a recipe wants, what goes wrong with too much or too little, and how to check that your tub of baking powder still works.

What a raising agent does in a pancake

A raising agent is anything that puts gas into a batter. The technical word is aeration. In a pancake, the gas is carbon dioxide. Tiny bubbles form throughout the batter, and as the pancake heats, those bubbles expand while the egg and flour starch set around them. When the structure is firm enough to hold, the bubbles stay behind as the soft, airy crumb you want in an American-style stack.

Without a raising agent, a thick batter has nothing to open it up. The result is a flat, dense, slightly rubbery pancake. That is exactly what you want in a classic British pancake and exactly what you do not want in a stack of fluffy ones.

Bicarbonate of soda: an alkali that needs an acid

Bicarbonate of soda is a pure alkali. On its own in a batter, it does very little to raise anything. It produces carbon dioxide when it meets an acid, and the reaction starts as soon as the two are wet and together.

That is why bicarbonate of soda is paired with an acidic ingredient. In pancakes the usual partner is buttermilk, and plain yoghurt, kefir, soured cream or milk with a spoonful of lemon juice or vinegar all do the same job. Because the reaction begins on mixing, a bicarbonate batter is best cooked fairly soon after it is made. Our buttermilk guide covers the timing.

If there is more bicarbonate than the acid can use up, the leftover bicarbonate stays in the batter. It tastes soapy or metallic, and because it makes the batter more alkaline, it also makes the pancakes brown faster than you expect.

Baking powder: bicarbonate with its own acid

Baking powder is a ready-made mix. It contains bicarbonate of soda, one or more dry acids, and a little starch to keep the powder dry and stable. Because the acid is already in the tub, baking powder works in a batter made with ordinary milk and no other acidic ingredient. Many baking powders are also double acting, meaning they react a little when they get wet and more as they heat, but formulations vary, so check the tub.

This is why most simple American-style pancake recipes use baking powder. You can use any milk, there is no need for buttermilk, and the batter is more forgiving if it sits for a few minutes while the pan heats.

Which one does your recipe need?

• Recipe with plain milk and no other acid: baking powder.
• Recipe with buttermilk, yoghurt or kefir: bicarbonate of soda, baking powder, or both. Many buttermilk recipes use both, with the bicarbonate neutralising the acid and the baking powder providing extra lift.
• Recipe with self-raising flour: neither, usually. Self-raising flour already contains a raising agent, so adding more risks the problems below. Our guide to the best flour for pancakes covers how the flours differ.
• Thin British pancakes or crêpes: neither. These are meant to be thin and flat. The science of British pancake batter explains why they rely on egg and steam instead.

The two are not swappable spoon for spoon. Bicarbonate of soda is much stronger than baking powder, so a recipe written for one needs its quantities reworked to use the other, and a bicarbonate-only recipe also needs its acid kept in. If you only have one and the recipe wants the other, it is usually easier to follow a different recipe than to convert.

British and American pancakes

A British pancake is thin, made from flour, milk, eggs and a pinch of salt, and it gets all it needs from the set egg and the steam in the pan. A raising agent would only make it puff and lose its flat, foldable finish.

An American pancake is thick, so it needs gas. That is why the American stack recipes use a raising agent, often alongside buttermilk, and why the science of American pancake batter spends so long on how the bubbles form and set.

What happens if you use too much

More raising agent does not mean more rise. Past a certain point, it causes problems:

• A soapy or metallic taste. Raising agent that has not reacted fully is left behind in the cooked pancake. This is the most common sign you have been heavy handed, especially with bicarbonate of soda.
• Over-browning. Extra alkali speeds up browning, so the outside darkens before the middle is cooked.
• Rising, then collapsing. If the batter produces more gas than the structure can hold, it puffs in the pan and then sinks, leaving a coarse, uneven, sometimes gummy crumb.
• Large, uneven holes. Too many bubbles join up into bigger ones rather than staying fine and even.

What happens if you use too little, or none

Too little raising agent, or one that has lost its strength, gives flat, dense pancakes that cook through but never rise much. Leaving it out of an American-style batter does the same. If your pancakes are coming out flat, check your raising agent first, then see why pancakes go flat, dense or rubbery for the other causes, such as overmixing and a pan that is too cool.

How to test whether baking powder still works

Baking powder loses strength over time, especially if the tub has been left open or stored somewhere damp. Testing it takes seconds:

1. Put half a teaspoon of baking powder in a cup or small bowl.
2. Pour over a few tablespoons of hot water.
3. If it fizzes up straight away, it is fine. If it barely bubbles, replace it.

Bicarbonate of soda can be tested the same way with a splash of vinegar or lemon juice in place of the water. It should fizz vigorously.

Tips for getting the lift right

• Mix the raising agent into the dry ingredients first. Whisking it through the flour spreads it evenly and avoids bitter pockets.
• Measure with a proper spoon. Level it off. A heaped spoon is a bigger error than it looks.
• Do not over-mix. Stir until the flour has just disappeared. Overmixing knocks out gas and builds gluten, and the pancakes turn chewy.
• Cook soon after mixing. Once the liquid goes in, the reaction is under way and the bubbles do not wait around.
• Get the pan properly hot. Heat is what sets the structure around the bubbles. A cool pan lets the gas escape before the pancake firms up.

For a one-page overview of how every ingredient in the bowl fits together, see what each ingredient does in pancakes.