We make scones for breakfast fairly often, because as we showed earlier, you can make them quickly and they are quite delicious.

But, a couple of days ago, we made some of the worst scones we’d ever made.

As you can see, the recent scones were a flat-out disaster. We had used new baking powder and everything, but they were a flop.  What had gone wrong?

Well, the immediate suspect was the baking powder. Baking powders sometimes fails because it was stored improperly: in a hot warehouse or truck, for example. Let’s explain how this works here.

Baking soda is just sodium bicarbonate, NaHCo₃. You use it when acidic ingredients such as buttermilk, sourdough or yoghurt are included in the batter. The baking soda will react with any of those acids to release carbon dioxide, CO₂, which causes bubbles that make the dough rise.

Baking powder is sodium bicarbonate mixed with one or more acids in dry crystalline form, such cream of tartar  (tartaric acid), monocalcium phosphate, sodium aluminum pyrophosphate, or a couple of others.  Double acting baking powders (and most of them now are) contain two acids, one that reacts immediately when liquid is added and one that reacts only when heat is also applies. In all cases, the baking powder also contains cornstarch, to help keep the mixture dry and add bulk to make it easier to measure.

But you can easily test baking powder by putting a couple of teaspoons in  a bowl, and adding boiling water. Just microwave a cup of water in a pitcher for a minute or so until it bubbles a bit, and pour it over the baking powder. It should foam up right away as you see below.

But let’s look at that suspect baking powder: no foam at all, it scarcely breathes a word!

In fact, it doesn’t really look at all like the other sample. In fact let’s look at the package:

Oh!

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