Why Does Baking Soda Absorb Odor?

Two experts explain why baking soda is such an effective smell-stopper.

Wooden spoon with baking soda
Photo: Getty/ EKramar

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It's been a household trick for generations: Sprinkling a little baking soda on everything from your cat's litter box to the bottom of the kitchen trash can reduce unpleasant odors. And while this trick generally works, you may not know why it is so effective. To get to the bottom of it, we talked to two experts, and here's what they have to say.

The Science Behind the Soda

The "why" behind baking soda's successful absorption of odors has more to do with chemistry than anything else, says Alex Reed, the co-founder of Truman's: "Most smells are acidic in nature, and baking soda can be a pH neutralizer." Simply put, the chemicals in baking soda are perfect at neutralizing the acids that cause bad smells.

The Best Way to Use It

For the best results, spread baking soda in a thin layer, explains Reed, which is why it does such a good job at combating odors when sprinkled across the bottom of a trash can or the surface of a litter box. But the fact that it really should be spread out to do its job to its full potential is what means it's less effective in the refrigerator. "Baking soda in the fridge will have a minimal impact on odors if the corner [of the box] is simply left open," Reed says. "It needs to be spread more evenly on surfaces to have a meaningful impact." Interestingly enough, the benefits of using baking soda as a deodorizer don't stop in your home. Trisha Lake, owner and CEO of TLC Cleaning, explains how it can battle personal odors, as well: "Very few people know that baking soda actually makes a great deodorant and works well in tennis shoes."

Keep Your Cooking Baking Soda Separate

It may be tempting to steal a pinch of baking soda from that open box in your refrigerator if you run out of the stuff in your cupboard, but that would be a mistake, says Lake. "When we utilize baking soda as an odor reducer, the molecules in the air react to the baking soda to grasp those odors," she explains. "If we were to take that same box and use it in our food, we would run the risk of having our foods' tastes altered." The reason? That baking soda has spent all that time in the fridge "grabbing" odor molecules and has since become flavored by everything that has a smell—which is probably not what you want to think about while whipping up a batch of chocolate chip cookies. For good measure, you should always keep your cooking and deodorizing baking soda separate.

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