How To Test Baking Powder for Freshness

Years ago, I was at a friend’s house and I wanted to make some chocolate chip cookies. When I went digging in her pantry, I found baking powder that had expired many, many years earlier. I tossed it, but, like my friend, I sometimes have some in my pantry that’s not the freshest and wonder: At what point is baking powder too old to use?

With baking season upon us, you’ll likely be asking the same question, so I checked in with a baking and pastry expert on how you can test your baking powder to see if it’s fresh.

“When properly stored, the shelf life of baking powder is actually indefinite, but the useful shelf life past its best-by date is approximately six to 12 months,” says Norma Salazar, chef-instructor of pastry and baking arts at the Institute of Culinary Education’s Los Angeles campus.

That’s why first checking the best-by date is important. “After that date, the manufacturer makes no guarantees of the quality of freshness the product will have,” says Salazar. “The taste may weaken; items may dry out, or stale. Essentially, it will not be bad or inedible; it just will not be at its best.”

How To Check Baking Powder for Freshness

If you do come upon an old jar of baking powder, there’s an easy way to test it for freshness before adding it to a recipe: 

• Mix 1 cup of hot water with 2 teaspoons of baking powder
• If it starts to fizz immediately, the baking powder is still fresh for baking
• If nothing happens, go shopping or make a substitution

“When baking powder is fresh, it will create a light and fluffy product,” says Salazar. “But if the product is not good to use, then your baked goods will collapse, be dense and heavy, and have a crumbly texture and not hold its shape after baking.”

How To Make a Baking Powder Substitute

Don’t be tempted to just double the amount of non-fresh baking powder in your recipe. Instead, it’s easy to make your own with some other baking staples.

• 2 teaspoons baking soda
• 4 teaspoons cream of tartar
• 1 teaspoon cornstarch (to prevent the mixture from clumping)
  

Mix the ingredients together and store in an airtight container.

Other Baking Powder Substitutions

If you don’t want to make baking powder from scratch, you can also replace it in a recipe with one of the following:

• Buttermilk (or 1 cup of whole milk with 1 teaspoon of lemon juice)
• Plain yogurt
• Molasses
  
• White vinegar
• Lemon juice
• Club soda

If you use a liquid like vinegar or buttermilk, you may need to decrease the amount of other liquids in your recipe to make up for it. “If you use the same amount of milk with lemon juice in the original recipe that required buttermilk or sour cream, it should hold its structure,” says Salazar. “But if the recipe calls for baking powder and you substitute it with club soda, you will need to increase the amount of flour by 1 to 2%.”

You don’t have to worry about the substitutions having much of an impact on taste. “Baking powder already has an acidic tartness, so cream of tartar, baking soda, vinegar, buttermilk, and lemon juice will not change the taste of the baked product,” Salazar says.

How To Store Baking Powder to Maximize Freshness

Proper storage is key to prolonging your baking powder’s shelf life. Keep it sealed in an airtight container in a dry place at room temperature.

Don’t be tempted to keep it in the fridge. “Refrigeration and moisture are the enemy of baking powder,” says Salazar. “When exposed to moisture, the chemical reactions in baking powder can be activated prematurely, resulting in a loss of its leavening ability.”