Cool leftovers quickly
A deep pot of soup loses heat slowly from its center. Bacteria multiply fastest between 4°C and 60°C (40 to 140°F), and a full stockpot put straight into the fridge can take 8 hours or more to cool through that range.
Shallow containers cool food faster
Get cooked food into the fridge within 2 hours. Heat leaves through the surface, so pour the food into containers no deeper than 5 cm (2 in), or set the pot in an ice bath and stir. The faster it drops from 60°C to 4°C, the less time bacteria have to grow.
Test yourself
Questions from the interactive lesson, with the answer and the why.
What's the best way to cool a big pot of chili?
Split it into shallow containers first. More surface area lets heat escape much faster.
True or false: Hot food should cool completely on the counter before it goes in the fridge.
False. Food left out for over 2 hours sits in the danger zone, so divide it and refrigerate within 2 hours.
What went wrong? You ladle a stockpot of hot soup into one deep container, seal the lid and put it in the fridge.
The deep, sealed container traps heat in the middle. The center takes many hours to cool.
Fill the blank: Dividing food into shallow containers works because it increases the ___ that lets heat escape.
Dividing food into shallow containers works because it increases the surface area that lets heat escape. More exposed surface sheds heat faster.
Roughly how long can cooked food sit out before it should be chilled?
About two hours, or one hour in a hot room. After that, bacteria have time to grow to risky numbers.
Shallow vs deep cooling
Why we cool food in shallow trays.
Do the 40-minute experiment