Why can you pressure-cook frozen meat?
March 27, 2017 9:41 AM Subscribe
So I just got an instapot, and one of the amazing features is the fact that you can drop in a frozen piece of chicken and have it perfectly cooked in no time. My highschool physics is not helping me understand why it's ok to do that with a pressure cooker but not by say baking it. My thoughts were baking may not get the temperature high enough in the frozen center for food safety. Is this not then true for pressure cooking?
As a bonus any handy recipes I can try?
As a bonus any handy recipes I can try?
Short answer: PV = nRT (or "pimp nert" as it was known in my high school).
posted by Alison at 9:55 AM on March 27, 2017 [2 favorites]
posted by Alison at 9:55 AM on March 27, 2017 [2 favorites]
Baking from frozen is a perfectly acceptable way to cook chicken.
From the US Department of Agriculture: "chicken can be cooked from the frozen state in the oven or on the stove. The cooking time may be about 50 percent longer."
posted by cooker girl at 10:02 AM on March 27, 2017 [2 favorites]
From the US Department of Agriculture: "chicken can be cooked from the frozen state in the oven or on the stove. The cooking time may be about 50 percent longer."
posted by cooker girl at 10:02 AM on March 27, 2017 [2 favorites]
Best answer: As I understand it, the failure modes with cooking from frozen are:
1. the middle doesn't get up to a safe temperature at all, like you suggested, which could happen with a frozen roast in the oven
2. the middle gets up to a safe temperature, but takes too long to do so, and therefore spends too long in the bacteria breeding temperature zone - like with a frozen roast in a slow cooker
3. the middle gets up to a safe temperature in a safe amount of time, but it still takes long enough that the outside is now overcooked and not as good - that's the case with frozen bits of chicken in the oven, especially if there's no sauce to stop it drying out.
So I reckon that using a pressure cooker on the bits of chicken would be quick enough to avoid all these failure modes, plus it's really wet in there so the chicken surface won't dry out.
I still wouldn't try the pressure cooker with a frozen roast!
posted by emilyw at 10:02 AM on March 27, 2017 [3 favorites]
1. the middle doesn't get up to a safe temperature at all, like you suggested, which could happen with a frozen roast in the oven
2. the middle gets up to a safe temperature, but takes too long to do so, and therefore spends too long in the bacteria breeding temperature zone - like with a frozen roast in a slow cooker
3. the middle gets up to a safe temperature in a safe amount of time, but it still takes long enough that the outside is now overcooked and not as good - that's the case with frozen bits of chicken in the oven, especially if there's no sauce to stop it drying out.
So I reckon that using a pressure cooker on the bits of chicken would be quick enough to avoid all these failure modes, plus it's really wet in there so the chicken surface won't dry out.
I still wouldn't try the pressure cooker with a frozen roast!
posted by emilyw at 10:02 AM on March 27, 2017 [3 favorites]
I still wouldn't try the pressure cooker with a frozen roast!
There's nothing different between beef and chicken when it comes to food safety issues in a pressure cooker. As long as the meat hits the correct pasteurization temperature for the necessary amount of time, you'll be safe.
The issue with beef is that, like emliyw said, you're cooking in a very moist atmosphere. Chicken can handle it - beef will fall apart. So pressure cooking beef is only useful if you're braising a tough piece of meat into a pot roast or stew.
posted by JoeZydeco at 10:36 AM on March 27, 2017 [1 favorite]
There's nothing different between beef and chicken when it comes to food safety issues in a pressure cooker. As long as the meat hits the correct pasteurization temperature for the necessary amount of time, you'll be safe.
The issue with beef is that, like emliyw said, you're cooking in a very moist atmosphere. Chicken can handle it - beef will fall apart. So pressure cooking beef is only useful if you're braising a tough piece of meat into a pot roast or stew.
posted by JoeZydeco at 10:36 AM on March 27, 2017 [1 favorite]
One of the ways to not get extremely gnawy overcooked-on-the-outside meat in the pressure cooker is to chunk it up into even-sized pieces that can reasonably cook through without overcooking (and all of the pieces cook through at roughly the same rate). You will get chewy stringy outer meat if you try to freeze a huge rump roast and then PC it - it won't be unsafe, but it will be unpleasant. So if you're buying meat to freeze for later, cut it first and then freeze it.
As others have said, for meat that doesn't need a massive amount of cooking time, you need to go smaller so that it goes faster before every bit of juice is wrung out. I just made carnitas yesterday and felt like I'd cut the shoulder pieces down too small but actually got it right on target, it turned out, since shoulder will dry out if you push it too hard at all. There's a little bit of an art to this, though, and I don't think anybody's done the legwork to identify the ideal size chunk for every type of meat yet.
posted by Lyn Never at 10:45 AM on March 27, 2017
As others have said, for meat that doesn't need a massive amount of cooking time, you need to go smaller so that it goes faster before every bit of juice is wrung out. I just made carnitas yesterday and felt like I'd cut the shoulder pieces down too small but actually got it right on target, it turned out, since shoulder will dry out if you push it too hard at all. There's a little bit of an art to this, though, and I don't think anybody's done the legwork to identify the ideal size chunk for every type of meat yet.
posted by Lyn Never at 10:45 AM on March 27, 2017
Best answer: Pressure cookers like the Instapot can increase the boiling point of water from 212 to 250 degrees which helps to bring about the Maillard reaction, which usually isn't possible when just braising or poaching on a stove top. An sufficiently hot oven can do that as well, but the dry atmosphere will almost certainly overcook the outside of the chicken breast before the inside has time to get to temperature.
A wet, hot, high pressure environment is probably a lot better for heat transference than a dry, hot oven.
posted by Fidel Cashflow at 10:51 AM on March 27, 2017 [2 favorites]
A wet, hot, high pressure environment is probably a lot better for heat transference than a dry, hot oven.
posted by Fidel Cashflow at 10:51 AM on March 27, 2017 [2 favorites]
Best answer: Besides raising the boiling point of water, the other thing that pressure cookers do is enable faster heat transfer to any food that is NOT immersed in liquid. Instead of (mostly) dry air surrounding the food, it's steam, and further it's at twice the usual pressure (2 atm instead of 1, or about 28 PSI instead of 14 PSI), so twice the mass interacting with the surface of the food per the PV=nRT equation mentioned above.
Another illustration of this effect, from the Wikipedia article:
"... steam and liquids transfer heat more rapidly than dry air. As an example, the hot air inside an oven at, say 200 °C (392 °F), will not immediately burn your skin, but the wet steam from a boiling kettle at 100 °C (212 °F) will scald skin almost instantly and 'feel' hotter, despite the steam (and water) in the kettle being at a lower temperature than the air inside a hot oven."
Ask me how I know that last example is true.
posted by intermod at 11:12 AM on March 27, 2017 [1 favorite]
Another illustration of this effect, from the Wikipedia article:
"... steam and liquids transfer heat more rapidly than dry air. As an example, the hot air inside an oven at, say 200 °C (392 °F), will not immediately burn your skin, but the wet steam from a boiling kettle at 100 °C (212 °F) will scald skin almost instantly and 'feel' hotter, despite the steam (and water) in the kettle being at a lower temperature than the air inside a hot oven."
Ask me how I know that last example is true.
posted by intermod at 11:12 AM on March 27, 2017 [1 favorite]
> I still wouldn't try the pressure cooker with a frozen roast!
There's nothing different between beef and chicken when it comes to food safety issues in a pressure cooker
Just for reference, the difference between bits of chicken and a roast here is that the roast is big and the bits of chicken are small! A big lump of meat is much less likely to get up to temperature all the way through in a short enough time to make it safe.
posted by emilyw at 12:02 PM on March 27, 2017
There's nothing different between beef and chicken when it comes to food safety issues in a pressure cooker
Just for reference, the difference between bits of chicken and a roast here is that the roast is big and the bits of chicken are small! A big lump of meat is much less likely to get up to temperature all the way through in a short enough time to make it safe.
posted by emilyw at 12:02 PM on March 27, 2017
Response by poster: Thanks everyone this was very helpful.
posted by aeighty at 9:08 AM on March 28, 2017
posted by aeighty at 9:08 AM on March 28, 2017
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