Baking Soda Vs Bicarbonate of Soda? What Every Family Baker Should Know

This is one of those questions that comes up in my kitchen at least once a fortnight (we do a lot of baking here), usually shouted through from the lounge by one of the kids halfway through reading out an American recipe they’ve found online. So, quick answer first, because I know you’re probably mid-bake with flour on your hands right now too.

Baking soda and bicarbonate of soda are the same thing. Exactly the same white powder, exactly the same chemical, sodium bicarbonate. If you’re in the UK and a recipe (usually American) asks for baking soda, just reach for your bicarb. Nothing to buy, nothing to convert, nothing to panic about.

What trips people up isn’t the ingredient itself. It’s everything around it: why two countries call it different things, how it’s different from baking powder even though they sound like cousins, and what actually goes wrong in the oven when you get the wrong one out of the cupboard. That’s the bit worth knowing properly, especially if baking is one of the ways your family spends a rainy Saturday together, which in our house it very much is.

So why does it feel like a different ingredient?

It’s purely a naming thing, nothing chemical. In the US, it’s baking soda. Here in the UK, it’s bicarbonate of soda, or just “bicarb” if you’re in a hurry, which in my kitchen is most of the time. Australia uses bicarb too. Same tin, different label, depending on which side of the Atlantic wrote the recipe.

I’ve lost count of the number of American recipes we’ve followed over the years, usually chosen by one of the children for a specific cake they’ve set their heart on, and the only adjustment I make is mentally swapping the word. The powder in the box is identical either way, which is honestly one less thing to worry about when you’ve got a nine-year-old convinced the recipe “won’t work in England.”

Bicarbonate of soda vs baking powder, where the real confusion lives

This is where I think the real confusion sits, and it’s the one that can genuinely change how a family bake turns out rather than just confuse you at the shop.

Bicarbonate of soda is pure and needs an acid to do its job, things like buttermilk, yoghurt, treacle, brown sugar or lemon juice. Mix it with something acidic and it starts fizzing straight away, releasing the carbon dioxide that gives your bake its lift. No acid, no proper reaction.

Baking powder already has that acid built in (usually cream of tartar), plus a bit of starch to keep everything dry and stable until you add liquid. That’s why some recipes use baking powder on its own quite happily, no additional acidic ingredient required.

What happens if you use the wrong one

I learned this properly with my ginger cake, one of our most-made family bakes and one of the very few times it sank in the middle. The cause turned out to be bicarb that had been sitting open in the cupboard for months. It still looked fine. It just wasn’t reacting with the treacle and milk the way it should have, so the cake didn’t get the lift it needed. Once I started using a fresher tin and keeping it properly sealed, that problem disappeared completely, much to the relief of whoever had been promised cake that week.

You’ll see the same acid-and-bicarb relationship at work in my banana and date loaf, where the bicarb goes in with the dates and boiling water rather than the flour. The heat and moisture soften the dates, and the bicarb neutralises some of their natural tannins, which stops the loaf tasting slightly bitter. Small step, but it’s the kind of detail that turns a decent loaf into one the kids ask for again.

Can you swap one for the other

In a genuine emergency, sort of, but it’s not a clean one-to-one swap and I wouldn’t do it for anything you’re baking to actually impress someone, a birthday cake or school fete contribution included.

If a recipe asks for bicarbonate of soda and you’ve only got baking powder, you’ll generally need roughly three times as much baking powder to get a similar lift. Going the other way, from baking powder to bicarb, is fiddlier because you also need to add an acid to make it work, so it’s not something I’d attempt mid-recipe without a proper plan.

Honestly, if we’re out of one, I’d rather send someone up the road to the corner shop than gamble on a cake that’s already got a name attached to it, ours nearly always do.

How much is too much

More bicarb doesn’t mean more rise, and this is the mistake I see most often, including one memorable batch of flapjacks where my eldest declared they “tasted like the inside of a swimming pool.” Too much bicarbonate of soda without enough acid to neutralise it leaves the excess unreacted in your batter, and unreacted bicarb tastes soapy and slightly metallic. It can also leave a yellowish tinge in the crumb rather than the pale, even colour you’re after. Chemistry-wise, that’s genuinely what’s happening: without enough acid, the bicarbonate simply doesn’t fully convert, and what’s left behind affects both the taste and the colour of your bake.

The batter curdling slightly once you add the milk in my sticky toffee pudding is a good example of this reaction actually working as it should, not a sign anything’s gone wrong. It looks a bit alarming the first time you see it, and I did nearly bin a batch over it once, but it bakes out completely.

Where I’ve used it across my own bakes

If you want to see bicarb doing its actual job rather than just reading about it, a few of our regular family bakes lean on it properly:

My Mary Berry soda bread is the simplest possible demonstration, just four ingredients, and the bicarb reacting with the buttermilk is entirely what makes it rise. No yeast, no proving, and it’s on the table faster than a trip to the shops, handy on the evenings when the bread bin is empty and three hungry kids are circling.

My Mary Berry ginger cake is where I learned the hard way what old bicarb does to a bake.

My banana and date loaf uses it in a slightly different way, soaked with the dates rather than mixed into the flour.

And my Mary Berry sticky toffee pudding shows the curdled-batter moment that catches a lot of people out the first time.

Is bicarbonate of soda the same as baking soda?

Yes, completely. It’s the same compound, sodium bicarbonate, just called different things depending on where you are. UK recipes say bicarbonate of soda, American ones say baking soda.

Can I use baking powder instead of bicarbonate of soda?

You can, but you’ll need roughly three times as much baking powder, and the finished texture and flavour will be slightly different because baking powder already contains its own acid. Fine as an emergency fix, not something I’d rely on for a bake that has to turn out well.

Does bicarbonate of soda go off?

Not in a food safety sense, but it does lose its reactivity over time, especially once opened. If your bakes have started falling a bit flat for no obvious reason, that’s often your first clue. A quick way to check is to drop a small amount into vinegar. A vigorous fizz means it’s still active.

What happens if you add too much bicarbonate of soda to a cake?

You’ll usually notice a soapy or slightly metallic taste, and sometimes a yellowish tinge to the crumb, because there isn’t enough acid in the recipe to fully react with it. It’s a genuinely easy mistake to make if you’re eyeballing measurements rather than weighing them properly, as I learned via the swimming pool flapjacks.

If you fancy putting it into practice, you’ll find plenty more to try over on my baking pages, from quick fixes like soda bread through to the bakes that took a few goes to get right!

Becky

Meet the award-nominated UK lifestyle blogger behind Spirited Puddle Jumper – a mum of three living in South East London! Becky shares the real ups and downs of family life, parenting tips, and lifestyle inspiration, proving that being a mum doesn’t mean you stop being fun or having other interests! Follow along for honest insights into UK family life and opinions on a whole range of topics, from travel and food, to beauty reviews, home and DIY, business and health and wellness.