Why You Should Never Transfer Hot Soup Straight to the Fridge

I myself have wondered why, as I ladle piping hot broccoli-cheddar soup or Tuscan white bean soup into lunch-size square containers, something feels off about depositing those steaming containers straight into my fridge. Turns out, my instincts were right.

Placing hot foods directly into the refrigerator can raise the appliance’s internal temperature to potentially unsafe levels, endangering the other perishable items stored inside. It’s the second law of thermodynamics at work: Heat will always flow from hot to cold. Placing hot soup into a cold environment means that heat transfers to cooler objects in the fridge, such as milk, meat, or cheese, potentially warming them to an unsafe temperature.

To avoid this, let your soup, stew, or other hot foods cool off the heat on the stove or countertop for about an hour, or until it reaches 75 degrees Fahrenheit. (This is a great opportunity to, you know, eat some of that delicious food.) After it’s cooled to 75 degrees, the food can be safely transferred to the refrigerator, which should be set to about 40 degrees.

If you’re planning to freeze your soup or stew leftovers, take special care with those that include dairy or pasta. These tend not to reheat well: The dairy curdles as it’s frozen, and the pasta turns mushy when reheated. Instead, cook and freeze the soup or stew without the dairy or pasta. As you’re reheating it, stir in uncooked pasta and simmer until the pasta is tender; or add the dairy and gently heat the entire soup through—just don’t let it boil, or the dairy will curdle.

(By the way, are you looking for the best plastic and glass containers for freezing and refrigerating? Look no further than our equipment reviews of the best food storage containers.)

Now that you know the ins and outs of refrigerating and freezing soups, go forth and cook them by the vatful.