This is one of the tools that restaurants use to cool down huge pots of stock and other hot foods when they're not going to be used right away. With all the soup we've been making lately, we're thinking about picking one up for ourselves!
Using an ice paddle cools food down much more quickly than simply letting them cool on their own or even setting them over an ice bath. It's not good to put very hot food directly into the refrigerator because it will make the fridge warm up - along with the rest of the fridge contents - faster than the fridge can cool it down. If food stays too warm for too long, it will start to spoil.
Ice paddles are made of sturdy food grade plastic, meaning they can interact with hot food without melting or releasing any harmful chemicals into the food. You fill them with regular water and leave them in the freezer until you need them. The smooth plastic is also easy to clean, and many of them are even dishwasher safe.
For home use, look for the smallest sized ice paddles - usually 64 ounces (or 2 quarts). They're readily available and affordable at any restaurant supply store or online:
• San Jamar Rapi-Kool Cold Paddle, $20 from Wasserstrom
You can also make your own using a leftover plastic water bottle, though we recommend waiting until the soup is no longer boiling hot before using it since commercial water bottles aren't made of the same grade of plastic.
Related: Fastest Way to Cool a Hot Beverage