Will it Fizz? How to Make Sure Baking Powder & Soda Are Fresh

Every week, baking expert Alice Medrich will be going rogue on Food52 -- with shortcuts, hacks, and game-changing recipes.

Today: Alice gets fresh -- with baking powder and baking soda, that is. 

Frequent bakers keep baking powder and soda in the cupboard and use them, as a matter of course, well before their “Use By” dates. If you are a new or very occasional baker, here’s what you need to know. 

Baking Powder:
Once opened, baking powder should be stored airtight using the handy snap-on cover provided. Do glance at the (generally conservative) “Use By” date from time to time. If you doubt your powder or wonder if you can get by using it after the “Use By” date, you can test it as follows: 

Spoon or pinch a little powder into a tiny dish and pour a bit of warm or hot water over it. The mixture should bubble in a lively manner and you should hear the fizz. If there is no bubbling or it doesn’t seem lively -- or you are just nervous -- get a new tin rather than waste time and ingredients baking with pooped-out powder. 

Above: Baking soda on the left, baking powder on the right.

Baking Soda:
Received wisdom, and every baking site on the internet, will tell you that baking soda has a shelf life and will lose its potency similarly to baking powder. Some sources say it should be used within 18 months and that humidity can shorten its life. 

I’m not so sure about that...  

While I am very careful with my baking powder because I know it can go dead, I’m quite cavalier with my soda! All of these years I’ve been leaving the open package unsealed in the cupboard and I’ve never had a problem with performance. Ever. But then I began to wonder: Could the internet be wrong?

So I found an ancient box of soda open in the back of my fridge with a 2009 “Use By” date. It was a little clumpy due to the humidity (and heaven knows what else it was exposed to in my fridge). I put a giant pinch of it in a tiny dish next to another tiny dish with a giant pinch of the soda from my baking cupboard, which is fresher but opened and unsealed. (I may be devil-may-care with my soda, but even I don’t use the stuff that’s deodorizing my fridge for baking.) Since soda activates with acid rather than water, I spooned a little vinegar into each dish. Both samples bubbled and fizzed happily.  

Bottom line: Be vigilant with your baking powder; don’t worry too much about the soda.  

P.S. I can’t wait to hear what the seasoned bakers among you will have to say on this subject! 

Above: Baking soda and vinegar on the left, baking powder and warm water on the right. 

Photos by James Ransom