It’s important that liquids are cool before you put them in the refrigerator; if the liquid is too hot, it will increase the temperature inside the refrigerator and potentially cause food to rise to unsafe temperatures.
To rapidly chill soups and stocks, our usual approach is to transfer the liquid to a bowl set in larger bowl of ice and whisk until cool. Since different materials transfer heat at different rates, we wondered if we could get faster results by using a certain type of bowl. We cooled 2 1/2-quart batches of hot soup in stainless-steel, glass, and heatproof plastic bowls, all with similar diameters, and timed how long it took the liquid to drop from 174 degrees to 80 degrees while stirring constantly. The differences were dramatic: Soup took more than twice as long to cool in glass as in metal and more than three times as long to cool in plastic. To encourage the quickest cooling, we’ll always be sure to transfer our hot liquids to a metal bowl since it transfers heat the fastest.
Transfer hot liquid to a metal bowl, set the bowl in a larger bowl filled with ice, and whisk or stir constantly.
Plastic: 36 Minutes
Glass: 26 Minutes
Stainless Steel: 11.5 Minutes