If you notice an odor when you open your refrigerator, it might be time for a deep clean. But even immaculate shelves and crystal clear crisper drawers won’t save your fridge from that not-so-fresh smell if you frequently fill it with fancy cheese and fragrant leftovers.
For most people, the solution is a box of baking soda.
Known scientifically as sodium bicarbonate, baking soda is an incredibly versatile kitchen staple. A necessary component of airy baked goods, it can also be helpful for getting that perfect golden brown color on bagels, taming the acidity in tomato-based dishes, and quickly softening legumes. And when your refrigerator starts to reek of all of those things (or worse), you can just tear open a box of baking soda, stick it in the door, and wait for it to deodorize the stench.
Does it work? Sure. But after speaking with Georgia Institute of Technology chemistry professor Anthony Rojas, it doesn’t work the way I’ve believed it did.
How baking soda makes your fridge smell better
The science behind baking soda’s deodorizing properties is an acid/base reaction. In this case, the food (no matter how bland) is the acid, and the baking soda is the base. To fully comprehend how this works in the fridge, it’s first important to understand that everything we eat is constantly in a state of flux.
As Rojas explained over Zoom, the microorganisms in food are always undergoing chemical processes that affect odor, appearance, and taste. At the same time, molecules are also traveling from the surface of those foods into the atmosphere, and the worst smells are often caused by the oxidation of those foods’ fatty acids. In other words: they’re the gaseous by-products of decay (and unless you have a live lobster or living basil plant in your fridge, everything in there is already in a state of decay).
Enter baking soda, which chemically speaking, is a base. If you happen to keep a box of it anywhere in your fridge, then there are microscopic sodium bicarbonate particles constantly rising up out of that box and moving around through the air, even if you can’t see them. Your refrigerator’s built-in fan gives them an added boost, as do you every time you open and close the door or rearrange a shelf, especially if you jostle the box.
As Rojas explains it, those mobile sodium bicarbonate particles are drawn to the stinky molecules and once they make contact—which happens in the air—the odor is neutralized.
How to use baking soda more effectively in the fridge
Because microscopic particles can penetrate cardboard, you could put an unopened box of Arm & Hammer in the fridge and baking soda would still manage to escape and neutralize odors. Eventually. Venting the top or using a fridge-specific product with a larger, mesh-covered panel simply allows the process to happen much more quickly because when more surface area is exposed, more particles are able to escape at once.
If the contents of your refrigerator are extra pungent, or if you want faster results, think outside the box and place smaller containers of baking soda on every shelf. It will give the particles more opportunities to enter the atmosphere of your fridge, and they won’t have to travel as far to reach their targets, either.
So how often do you really need to replace the box of baking soda?
According to Rojas, since the reaction happens in the air, as long as there’s still baking soda in the box, the box is still doing its job.
So instead of spending your money on a new box of “fridge” baking soda every month, buy a few fun dispensers, fill them up once, and leave the rest to science. For a while, anyway.
