Ask Peter: Baking powder
I have noticed a few recipes (an apple cakeand a simple scone recipe) that feature quitea lot of baking powder: 6 tsp in the scone recipe, which had 500g flour. I thought the general rule was that you use about 1 tsp baking powder to 1 cup flour — both of these recipes had more like 2 tsp to 1 cup of flour. Can you give me a rough idea of how much baking powder is too much; i.e. at what point would you start to get that chalky taste? This would help my confidence in making recipes that I currently put aside thinking they may have made a mistake.
There really isn’t a hard and fast rule for the amount of baking powder to flour you must have in a recipe. If you’re making a recipe that has a lot of dried fruit, mashed bananas or apple chunks, or creamed butter in it, then it’s likely it’ll need more baking powder to flour than a simple plain scone. Mostly it is more about what else is in the mixture.
I did a search of online recipes and the most consistent response was that usually you use between 1 to 2 teaspoons of baking powder per 1 cup (150g) of flour. From a scientific point of view, that is almost a pointless quantity. Is it one, or is it two? One is double the other, so surely they can’t be interchanged. Understanding the way baking powder works may help with your baking though.
Baking powder is a combination of a powdered alkali (usually bicarbonate of soda, or baking soda, as it’s more commonly known) and a powdered acid (usually cream of tartar). It will probably also contain a small amount of another fine white powder to prevent the mixture from lumping together and keep it dispersed and this might be rice flour or cornflour.
Once water is added to the mixture, the hydrogen and oxygen molecules in the water react with the molecules in the alkali and acid, and carbon dioxide is produced. The carbon dioxide fizzes away in the batter, causing larger bubbles to form and lump together, which in turn cause your cake or scones to rise. The bubbles expand the batter, and once heat is applied, the eggs in the mixture or the protein in the flour sets and the cake firms up. Once cooled, the cake settles a little then stays firm — with all the bubble walls now set solid.
It’s the imbalance in the ratio of the alkali and acid components that can give a finished recipe a bitter chalky flavour. Depending on what you’re making you might just need to tweak it every now and then. I’ve had the most delicious, fluffy scones made using self-raising flour, plus extra baking powder. That might seem to be a bit odd, but they were really delicious, and obviously had a higher ratio of baking powder to flour than usual.
Interestingly, when I had a broken one straight from the oven it did taste quite chalky, but when I had them served a few hours later at raising agent room temperature, smothered with feijoa jam and cream, I didn’t notice the bitterness at all. There was enough other flavour to mask the baking powder excess, so perhaps, in some cases, the textural benefit of an over-risen-super-fluffy scone outweighs the slightly odd flavour.
To make your own baking powder, mix 1 teaspoon cream of tartar with ¼ teaspoon baking soda. Any more baking soda and the finished cake may taste a little too chalky. Any less and the cake probably won’t rise enough.
The reason self-raising flour exists in the first place is so that you needn’t have a tub of baking powder in your pantry that you may rarely use. But don’t worry if you don’t have it – simply add 1 level teaspoon of your homemade or shop-bought baking powder per 120g plain flour. That’s a good starting point anyway.
In our Ask Peter series, executive chef Peter Gordon answers your curly culinary questions. If you're stumped over something food-related, send your question to email@example.com and keep checking in for answers. You can read more on Peter on his website, have a read of his Ask Peter articles or check out his recipes here.