Dear Home Ec 101,
I was hoping you might be able to explain how a water bath thaws out a chicken faster than sitting on the counter when the water is colder. Also, why is it safer ? It seems to me the water would just be a good place for germs to grow.
Perplexed in Perkaise, PA
Yay! We have a science question, we haven’t had one of these in ages. What you are asking about is called heat transference, which is the way heat gets from one thing to another. Heat always moves from warmer things to cooler things, this is phenomenon is described by the Second Law of Thermodynamics. In any system, in this case chicken and the surrounding air or water, the energy involved is trying to reach a state of equilibrium.
When a cold tray of chicken is sitting at room temperature on the counter, room temperature molecules, like carbon dioxide, bounce off the package and transfer a little of their heat to the chicken. Remember, atoms and molecules as gases are very far apart (relatively people, relatively) so they can only interact so much.
When the tray of chicken is immersed in cool water lots of molecules interact with the package of chicken transferring their heat. Even if your ground water is pretty chilly, the sheer number of interactions speeds up the process.
Now, why doesn’t the water turn into a giant bacteria farm? The short answer is, it does. However, the proper way to thaw chicken in a water bath is to either change the water every twenty minutes or to trickle water into the water bath allowing the excess water to spill out. In the first scenario bacteria doesn’t have time to grow to dangerous levels and in the second the water is continuously being replaced, flushing away bacteria.
*Edit* The chicken should be in leak proof packaging. Waterlogged chicken is nasty.
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