How long to keep baking powder?
I've got some two year old baking powder. I've made some baked items with it and everything seems fine. Can I keep using this container or should I get a fresh one? Thanks
Interesting that you say that. I was at my mom's today, starting the baking for the holiday gifts and needed baking powder. The can in her cabinet was outdated by, get this, 5 years. I was already too far into the recipe to turn back. I took the risk. It worked out fine. But I think that if I were checking ingredients in advance, I would probably go for a new container rather than risk it. The last time I bought new, I bought a smaller can. More expensive per ounce, but I figure if I toss it down the line, I would probably be tossing less...
Shake up your can of baking powder as the top stuff may not be as reactive. Take about a teaspoon of your powder and add some hot water and mix. Wait and you should see it bubble or react (foam up, etc. not going to be a violent reaction.) If there is a reaction it is still good to use as baking powder is a mixture of cream or tartar (acid) and baking soda (base) and adding water causes a reaction. If there is no reaction, toss it out as it won't leaven your food anymore.
When I still used store bought baking powder, I got in the habit of writing the date on it and replacing it every 12-18 months, just to be safe. It doesn't cost that much, especially compared to all the other ingredients you waste if it does go bad. And while it may have worked okay in some recipes, it may not in others, depending on the balance of ingredients in the recipe.
It may depend on how it has been kept. BP is activated by two things - adding water, and by heat (in the oven). That suggests that a closed can (with the typical plastic lid) in a relatively cool, dry location, should keep longer than one that has been exposed to warm, humid conditions.
I don't recall anyone describing how it goes bad, but I am guessing that if it gets damp, some of the baking soda and acid will react. So you could end up using a mixture that is half inert reaction products, and only half the expected amount of reactive ones. Thus it would be half as potent as fresh BP. But if dry it could be nearly as potent after two years as when freshly opened.