Does baking powder go bad?
Unless you’re a keen baker, an open container of baking powder is likely to sit in your kitchen cupboard for quite some time. That time can be months, or sometimes even years if you only use this leavening agent once in a while. At some point the question arises “is baking powder bad?
Since this baking ingredient is just powder, you may think that it lasts more or less indefinitely. That is, if the water does not reach it, what harm can happen?

Unfortunately, that is not entirely true. Although the powder will remain safe to use practically forever, it won’t do its job as a leavening agent forever. In other words, at some point, you can add it to your baked goods and they won’t rise like they should. Or at all. When this happens, it means that your baking powder has lost its potency.
If you want to know more about baking powder storage, shelf life, spoilage, and potency, keep reading.
How to store baking powder
You should store baking powder in the same way as other powdered products, such as wheat flour, baking soda, or cream of tartar. That means you should store the package in a cool, dry place. As with almost all powders, you should store them away from any source of moisture.
Once the package is opened, keep it tightly closed. As you can see, it’s not rocket science.

How long does baking powder last?
Most packets and containers of baking powder come with an expiration date. This date tells you how long, at least, the product retains its quality. In the case of baking powder, it’s just a rough estimate. So you can easily assume that an unopened packet of baking powder will work as it should after that date.
How long exactly? It’s hard to tell. I would suggest that if you open a package of baking powder that is more than three months past its expiration date, you test its potency before using it. So you will know if the powder is still working or not.

Once the container is opened, most sources suggest that you should use it within half a year. In short, once the air reaches the container, the powder starts to lose its potency a little faster, hence the 6 month recommendation.
ADVICE |
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If your baking powder has been open longer than six months, always check its potency before using it in a baking project. |
Pantry | |
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Baking powder (unopened) | Better before + 6 months |
Baking powder (open | 36 months |
Please note that the above periods are only rough estimates. If you store baking powder for a long time, check its potency before using it.
How to tell if baking powder has lost its potency or is bad
As I mentioned before, baking powder doesn’t go bad in a way that it’s unsafe to eat unless some water or other substances get on it. Unfortunately, there is no visible sign that the powder is still potent. Fortunately, there is a way to check if our baking powder is doing its job.
Take a third cup of hot water and add a teaspoon of baking powder to it. If the prepared mixture bubbles, the baking powder is good enough to use. It should look like this:

If there are no bubbles, it means that it has lost its potency, and you can discard it.
ADVICE |
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If you only have a teaspoon of baking powder left, and it’s been sitting for a long time, it’s safer to throw it away. Baking powder is fairly cheap, and it’s less expensive to buy a new packet of baking powder than it is to throw away a spoiled cake. |
Of course, if there is something wrong with the powder, such as mold or any other growth on the package, you should throw it away. This most likely means that moisture has found a way into the container.