Just got a question from one of my readers that might be of interest to others.
I was hoping you can answer this question for me. I have been looking stuff up on simmer and boil and how they are related to chicken. I notice that when I simmer chicken breast for an hour it's still raw inside but then everything I read tells me not to boil chicken for an hour because the meat will harden. Is this true? If it is how to I cook this chicken? I guess what setting do I put the stove on after I bring the stew/soup to a boil. I tried putting it on the lowest setting and that does not seem to cook anything. Also if you take a brisket for example and boil it after 3 hours it softens. Is it the reverse of the chicken? By boil I do not mean huge bubbles coming up to the top and trying to escape. I mean 'medium' setting on the stove.
1) The burner settings don't mean anything. Low on one stove and on another can be completely different. If you want to compare apples to apples, stick a thermometer into the liquid to get a temperature. When the recipe says to cook on low, medium, or high, it's just a suggestion of what setting to try first, then you need to adjust as needed.
2) "Boil" and "simmer" are very imprecise terms. Rolling boil = 212F (100C), but the water will start to bubble around 205F. Simmer is all over the place. Visually, it means an occasional little bubble breaks the surface of the water. The temperature should be around 200F. You can cook at many other temperature, but traditional recipes rarely give them a name. When one stove is set to "low," the liquid might hover around 200F, and on another stove it can drop all the way to 180F. This changes the duration a lot. The cooking graph is not linear, so 20 degrees could in some cases double your cooking time (I am not sure on exact number and it does depend on the shape of the ingredient, but want to give you an order of magnitude). Covered and uncovered pots make a huge difference too. When the pot is covered, the pressure inside builds and the same burner setting can produce a completely different temperature inside your pot.
3) What you are describing with brisket happen when the collagen (connective tissue) in meat converts to gelatin and then meat fibers start to shred. For this to happen, not only does the meat need to reach a certain temperature, but it needs to be held at that temperature for a particular duration. That's why the brisket won't cook much faster if you cut it into little pieces. 3 hours is about right for beef. The same will happen for chicken, but it will take about 2 hours given the cooking liquid is 205F. The only problem is that the chicken breast is a bad cut to cook this way. It has very little fat or connective tissue, so although it will shred eventually, it will be very dry. The cuts you want to choose for this long and slow method (simmering, stewing, braising) are fatty and tough -- thighs for poultry, shoulders and bottom of the leg for mammals.
4) About the warnings of meat hardening. It doesn't matter what temperature you cook at, but what temperature you cook to (the internal temperature of the meat). To understand how this works, watch my roasted chicken breast video. I cook it at a very high heat, but to a very low temperature and it's very soft and juicy. Keep in mind that normal home cook recipes are written for people without thermometers but with desire to observe FDA temperature recommendations.
5) Here is how I would add chicken to soup. Buy bone-in chicken thighs, remove the skin and make stock with them (200F for about 2 hours uncovered after the boil is reached). Remove them from the stock and cover (so that they don't dry out). Make the soup using the stock. When the soup is done, shred the chicken thigh meat and add to soup. To use the breast, I would roast it (like in the above video -- you can salt right before putting it in the skillet instead of a day ahead if time is time). Remove the skin, cut it up and add to soup right before serving -- don't simmer it, just let the hot soup warm it up.