Baking powder and baking soda are two common ingredients used in cakes, pies, breads and other baked goods. They are also two common ingredients that can expire. Fortunately, there are ways to test if baking powder or baking soda is expired.

What You'll Need

-Baking soda or baking powder
-Jar with a lid
-Newspaper or a cloth
-Open the jar of baking soda or baking powder and pour it into the jar. If you see any clumps, the baking soda or baking powder is expired and should be discarded. If there are no clumps, the baking soda or baking powder is still usable.
-Remove the lid from the jar and place the newspaper or cloth over the top of the baking soda or baking powder. Shake the jar gently to mix the ingredients. The mixture should form a thick paste. If it does not, the baking soda or baking powder is expired and should be discarded.
-If you want to measure out a specific amount of baking soda or baking powder, spoon it into a measuring spoon and pour it into a bowl.

The Method

If you have a baking powder or soda can that is past its expiration date, do not use it in your recipe. Instead, test the power by using this simple method: mix 1 teaspoon of baking powder or soda with 1 cup of hot water. If the mixture bubbles and foams, the baking powder or soda is still usable. If the mixture does not bubble or foam, the baking powder or soda is expired and should be discarded.

What to Do If Your Baking Soda or Baking Powder Is Expired

If you've ever wondered if your baking soda or baking powder is expired, there are a few easy tests you can do.

The first test is to measure how much liquid the substance will dissolve in. If the powder dissolves completely in water and the container has been sealed properly, then it's probably still good. If the powder doesn't dissolve easily or at all, it's likely expired.

Another test you can perform is to heat up the substance until it starts to smoke. If the baking soda or baking powder releases an unpleasant smell and starts emitting sparks, then it's expired.

If either of these tests indicates that your baking soda or baking powder is expired, don't use it - discard it and buy new supplies.

What to Do if Your Baking Soda or Baking Powder Has a Bad Odor

Baking soda and baking powder can develop an unpleasant odor if they are not used up or if they have been stored improperly. If your baking soda or baking powder has an unpleasant odor, the first step is to determine if it is expired.
There are a few ways to test whether your baking soda or baking powder is expired. The most accurate way to determine the expiration date of a baking powder is to weigh it on a scale. However, this is not always possible because some powders are in small packages and it is difficult to measure them accurately.
Another way to test whether a baking soda is expired is to smell it. If the smell of the baking soda is strong and unpleasant, it likely has an expired date. However, it is important to note that not all smells indicate an expired product. For example, vanilla extract and other spices may have a unique smell that may not be indicative of an expired product. In cases like this, it is best to try using the product before determining its expiration date.
If none of these methods work to determine the expiration date of the baking soda or baking powder, then the product likely needs to be thrown away.

Conclusion

If you're like most home cooks, you probably just grab a can of baking soda or baking powder without testing to see if it's expired. But checking the expiration date on your baking powder or soda can help ensure that it doesn't spoil and create unwanted messes in your kitchen. Here are three simple ways to test whether your baking powder or soda is expired:
-Smell the powder. If it smells bad, it's probably expired.
-Feel the powder. If it feels gritty, it's probably expired.
-Look at the packaging. The expiration date should be printed right on the package.

Reference :

https://www.thekitchn.com/how-to-test-if-baking-soda-or-baking-powder-is-expired-tips-from-the-kitchn-111759

https://www.tasteofhome.com/article/testing-baking-powder-and-soda/

https://runawayrice.com/cooking-basics/test-baking-powder-still-good/

https://www.thespruceeats.com/how-to-tell-if-baking-soda-is-still-good-1388327

https://www.gygiblog.com/blog/2020/01/09/baking-soda-expiration/