That Baking Soda in Your Fridge Probably Isn't Doing Much

Deep in the back of many refrigerators sits a small orange box with one of the top corners torn off—or, in some cases, a bowl of white powder. That, of course, is (probably) baking soda, and it was placed there to absorb any food odors in the fridge.

If this is something you do, chances are your parents, grandparents, or other people in your life swear by this longstanding method for minimizing bad smells, and instructed you to do the same thing. Maybe you swear by it, too, and have always enjoyed a fresh-smelling fridge.

Or, perhaps, you’ve wondered why your own refrigerator is seemingly immune to baking soda’s supposed odor-eliminating powers, and continues to stink no matter how often you switch out the box or bowl of the stuff. If that’s the case, it’s not (necessarily) you or your food: Baking soda simply isn’t equipped to tackle all odors. Here’s what to know.

How baking soda is supposed to work in your fridge

The gross smells in your fridge come from a variety of molecular compounds, Joe Schwarcz, PhD of McGill University explains. When food spoils or rots, it releases volatile fatty acids, which bases—like baking soda—should be able to neutralize upon contact, eliminating their odor in the process.

For example, when butter goes rancid, it releases foul-smelling butyric acid. When it reacts with sodium bicarbonate (aka baking soda), odorless non-volatile sodium butyrate is formed. Ta da.

Why the baking soda in your fridge isn’t working

If baking soda has always worked for you, that’s wonderful—you’re all set. But for everyone else, there are a few different reasons why you’re still dealing with foul smells in your fridge, despite having a box or dish of it on a shelf:

It’s been in there too long

While baking soda is capable of reducing some mild-to-moderate food odors, after some time has passed, it will start taking on the bad smells of the volatile fatty acids it previously neutralized. This is why swapping your old baking soda for some that’s fresh is recommended every three or so months.

Interestingly, Arm & Hammer recently updated their guidance, and now recommends replacing the box of baking soda in your fridge every 30 days, instead of every three months, based on their “continuing research efforts.” Of course, that also means they sell more baking soda, but either way, if the box or dish in your fridge has been there longer than three months, it’s probably not working, and may be making the smells worse.

Baking soda is powerless against certain odors

Although baking soda may be able to handle many mild-to-moderate food smells, not all bad fridge odors come from food, Schwarcz explains. A mix of bacteria and household mildew often found in refrigerators and freezers can produce a variety of disgusting-smelling volatile acids that baking soda can’t neutralize—no matter how fresh it is.

Not enough surface area is exposed

Baking soda works when the individual sodium bicarbonate crystals come into contact with stinky volatile fatty acids and neutralize them. So if you’ve only opened one small corner of a box of baking soda, it’s not going to do much.

How to eliminate more odors from your fridge

Baking soda may not be a magical smell-remover, but there are ways you can make it more effective:

Expose more surface area

Instead of opening a corner of a box—or even tearing off the center of boxes designed to go in the fridge or freezer—pour at least one cup of baking soda into a shallow dish. And don’t forget to change it at least every three months.

Deep-clean regularly

If your fridge is especially stinky, remove the rotten item—and any leaking liquids or powdery molds it leaves behind—ASAP, and clean the shelf or drawer where it had been stored. Tackle these issues right away, and even if you never let it get to that point, deep-clean your fridge regularly to keep it smelling fresh.

Use activated charcoal

Place one cup of activated charcoal powder or pellets in an open, shallow dish, and replace every month. You can do this instead of or in addition to using baking soda.