Can someone knows these types of things answer my question: I thought you weren't supposed to cook frozen raw meat? I thought you are supposed to thaw it in the fridge first. That may well have been why it turned out bad.
HTC, not so sure about frozen chicken but I will take the opportunity to mention that frozen hamburger patties turn out GREAT on the grill. The outside doesn't burn and the middle stays very juicy even when cooked well done. I don't thaw anything in the fridge because it takes days and I've never had any problem thawing at room temperature. My two cents!
sushi, that's the scum stuff, just take a spoon or laddle and skim if off. Though if you're not using the broth, you could probably just leave it and it won't hurt...It would be there even if your chicken were thawed.
Charcoal, I didn't even think about frozen patties. I guess it would be ok to cook frozen meat. I try to defrost in the fridge (if I plan ahead enough), since that's the "proper" way, but *shhhh* sometimes I defrost your way as well. It's much faster and that's how my Mom did it when I was a kid...I'm still alive and kickin!
The brown foam scum is proteins - definately skim it off, it doesn't taste good.
The yellow stuff is fat - wait until the "stock" cools off and you'll be able to skim more of it off ... when it's cool and you put it in a container in the 'fridge overnight all the fat will congeal at the top and you can lift it all off even easier. Of course, this "schmaltz" is to a Jewish Grandma what rendered bacon fat (Bacon Drippin's) were to my southern (USA) Grandmas.
While you can fry a frozen beef burger pattie with fairly good results - it doesn't work the same with a frozen chicken - the chicken is thicker and needs to be cooked to a higher internal temp than a beef pattie - rare beef is ok, rare chicken is a no-no.
Why is it tough? Norgeskog was definately on the right track - when you heat proteins they contract - how they are heated impacts how tightly they bunch up - and that makes meat tougher. This goes along with what HTC said .... you throw a frozen chicken into a pot of boiling liquid and your going to have the proteins in the meat seize up as quickly as they thaw.
Next time - thaw the chicken first .... and then let it sit at room temp for about 30-minutes to an hour to get it near room temp (assuming your kitchen is about 70-F). Then, when you cook it, start it in a pot of COLD (room temp or so) liquid. Since the heating will be more gentle the proteins will not seize up as tight.
Michel pretty much nails it on the head so all I can add is this:
Freezing the chicken breaks up the celular structure releasing a large amount of it's moisture. If at least thawed you would avoid some of this loss but adding it into a broth while frozen means it's taking even longer to cook while it's internal moisture is sucked out by osmosis.
Also boiling in general is not the best thing to do with chicken despite hwo popular it is... all the fat that contributes to it's taste and texture is lost in the process.
Lugaru just made me realize I had an almost fatal brain f*rt .... boiling is NOT the best method. You were talking about boiling and I got tunnel vision. Well, I was on the right track about the simmering - but Alton Brown made the brain click over ... you want to poach it! Similar to what I originally said ... but a little different technique.
Bring the water to a boil and add the defrosted chicken ... let it boil for 1 minute (gas cooktop) or 30-seconds (electric cooktop) ... then reduce the heat and maintain the temp of the liquid at 165-degrees F until the internal temp of the chicken is 165-F. The reason for the "boiling" period is to kill any surface bacteria.
It still works out to be about the same thing - just a little different way to do it. I'll admit that about the only time I boil chicken is to make stock, soup, or diced chicken with long-grain and wild rice with mushrooms. I've never tried it AB's way ... but the next time I do my chicken and rice I will.
If you start cooking a frozen chicken the outside will cook more quickly than the inside and you get a result of the outside of the chicken being too overcooked and the inside not cooked enough.
I do pretty much what Michael does. Defrost chicken completely in frige. Then bring water up just until it covers the chicken. Add any vegetables. Bring to to a boil. When it reaches a boil trun heat to low and cover with lid. Cook until done about 1-11/2 hours. During cooking process skim off scum as it cooks.
Another way to avoid tough meat in a soup or broth is to never allow the liquid to boil. That is, keep it at around 200 degrees. This is sufficient to cook the meat to a safe temperature, but not enough to toughen it. Ideally, the meat temperature should be no more than 170 degrees.
I use skins and carcass, or bones if not working with poultry, to flavor the broth. The meat is cooked seperately until done to my liking, then added to the soup after everything in it is cooked and tender. that way, the meat is perfect and not overcooked.
I also use the same technique of chilling the broth overnight in the refrigerator, and removing the hardened fat the next day. The liquid has gelled, telling me that it has absorbed the collagen, nutrients, and protiens from the bone and marrow, and will taste great when seasoned. Then I add the veggies and grains, cook until tender, serve in bowls, and add the diced and cooked meat to the bowls.
It's a bit more work, but the results are IMHO, very much worth it.