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Cook My Meat: heat diffusion through meat over time (csail.mit.edu)
226 points by tomkinstinch on Dec 17, 2018 | hide | past | favorite | 66 comments

I'm one of the 3 MIT students (now MIT alumnae) who coded this over 5 years ago now. It's popped up around the Internet again in the past year or so, which is neat but also a little cringey, because it forces me to look at code I wrote when I was a lot newer to programming than I am now.

One person commented about a better simulator that they'd developed, which I am certain exists. This simulator was developed for an EdX class called the Science of Cooking. Although we tested it and found it to be largely accurate (in one of the more delicious code testing sessions I've ever attended), it was designed primarily to illustrate the various reactions that occur at the molecular level, rather than to provide actual cooking guidance.

Also, it seems that some of you are having problems where the program crashes your browser. Unfortunately, that's not entirely avoidable as the whole application is client-side javascript, and does some moderately complex calculations for heat diffusion. Obviously this would not be the approach I would take if I were to rewrite the program today...

If anyone wants to take a look at the source code, here is the original git repo: https://github.com/laurabreiman/science-of-cooking. Cheers everyone!

Great work! I had a similar idea a decade ago when I wrote a calculator to solve for perfect cheesecake. The idea was to have thick New York style cheesecake with perfect texture top to bottom yet have caramelized top and bottom (no water bath cheating!)

We built a somewhat better thermodynamic model into the Pantelligent iOS and Android apps -- i.e. user would select 1" thick steak, medium, and then we'd use the real temperature signal to adjust the cooking time.

The key fact this simulation is missing is that the outermost layer of the food quickly becomes dehydrated, at which point its thermal conductivity drops dramatically. This is good! It allows for much more uniform internal temperatures.

Edit: we did a lot of thermal simulation using my CircuitLab simulation engine (https://www.circuitlab.com/) -- circuit models for thermal simulation are common, where voltage represents temperature, and current represents heat flow. The simulation engine allows for arbitrary behavioral elements like algebraically-defined resistors, which lets you model this "outer layer dries out" behavior quickly.

Is Pantelligent not available anymore? I was actually just looking for it as a possible xmas gift a couple weeks ago.

Just found an old GIF animation from a finite element simulation of cooking: https://imgur.com/a/ZX1n5Wx

(The "meat" flips in the middle when it disappears for a frame)

I'm impressed but disappointed the "reverse sear" is missing. If you haven't tried, it, it's a pretty amazing way to cook a steak and it scales up to lots of steaks at the same time.

It's awesome

[1] https://www.seriouseats.com/2017/03/how-to-reverse-sear-best...

Just make your own. Or click "as text" and paste this in:

  3cm Steak starts at 23°C
  110°C and 110°C for 2:00
  23°C and 230°C for 0:15
  230°C and 23°C for 0:15
  23°C and 23°C for 20:00

2 minutes of cooking for reverse sear? In practice, a 3cm steak would probably need 20-25 minutes at 100C before sear. This model seems way off at this temp range, but seems closer for sous vide.

Yeah I just flipped the sear then cook low and then adjusted it to medium rare. It seemed short to me too.

The chart on that page reads:

Temperature and Timing for Reverse-Seared Steak For 1 1/2–Inch Steaks in a 250°F (120°C) Oven

Doneness Target Temperature in the Oven Final Target Temperature Approximate Time in Oven

Rare 105°F (40°C) 120°F (49°C) 20 to 25 minutes

Medium-Rare 115°F (46°C) 130°F (54°C) 25 to 30 minutes

Medium 125°F (52°C) 140°F (60°C) 30 to 35 minutes

Medium-Well 135°F (57°C) 150°F (66°C) 35 to 40 minutes

I tend to do something around 75-80c for an hour on a 3-4cm thick steak. The slower one goes, the easier it is to make up for errors in probe placement, multiple steaks, etc.

One thing to note is that reverse sear was his answer to sous vide being too expensive. He does note that there are upsides and downsides to both, but the world has changed and these days precision sous vide circulators are dirt cheap.

I've tried both and much prefer the reverse sear to a sous vide steak. Getting a good sear on a wet steak is pretty difficult.

I will say that sous vide steaks make good camping food. I get vacuum sealed ones, cook 'em in the bag, toss 'em in my cooler and when it comes time, they can be dried with a few paper towels that then get tossed in the fire, some salt and pepper, and put a steak on a spit like a marshmallow.

That's a great idea!

Kenji Alt has gone into some depth on the tradeoffs between reverse-sear and circulators. There isn't much downside to reverse-sear; you get superior browning (the same quality browning on a circulated steak will give you a grey band), and basically just trade off not having to keep track of time.

Yeah great tip.


Serious Eats is the hacker news for cooking.

Once, Nathan Myhrvold spoke at Google about Modernist Cuisine and I asked him how to make the ultimate BBQ ribs (he won some competition). He said "sous vide, liquid nitrogen, then deep fry". Glad to see this site includes sous vide + liquid nitrogen.

For ribs I follow a modified 321 method, 3:30 on, 1:30 in tinfoil on, 1 unwrapped. Sauce them 10-20 minutes before they are done just to carmelize it a bit.

They are still tender but with A bit of toothiness left.

you're describing classic ribs (not sous vide, liquid N, or deep frying), right?

It's funny you mentioned that because the other point Mhyrvold and I discussed was using aluminum foil to tightly wrap the ribs during cooking- eliminating the water vapor that forms around the meat, which contributed to barbeque stall. Should speed up cooking without negatively affecting the results by 2-3 hours.

I was describing my method of BBQ in response to the gp. deep frying sous vide, liquid n or whatever other method is not bbq. Just like grilling is not BBQ. The style has a fairly specific meaning. If your ribs don't sweat three times in the process over six hours, you are doing it wrong.

Foiling them locks in the moisture. It absolutely doesn't eliminate it.

6 hours, low and slow. Or its not passable as BBQ

This technique is sometimes called "cryo frying".

Once upon a time I ordered a pizza at a pub in Glasgow. The barman plucked s pizza out of the freezer with tongs and dropped in in the Fryalator. It was less horrifying than it appeared to be.

Cooking the meat is cool. But, being someone of french gastronomical culture, I to to lean to Fernand Point saying : "Du beurre ! Donnez-moi du beurre ! Toujours du beurre !"

(basically, butter, butter, butter).

There was a recipe from G. Ramsay where it show to first sear the steak in oil, then, finish it with a bit of butter. It adds flavor and prevent the butter to burn.

I also tend to use my finger to test if a steak is fine. I'm no expert, but it works 80% of the time (to get a good steak). Now I must admit that sous-vide gives a lot more control and helps to reach the medium cook on a much wider part of the meat.

I threw away the finger technique, and now I use an instant thermal probe. Works 100% of the time.

+1 for the beurre, but don't forget to buy more for the sauce! It's all about the sauce.

Yeah but the finger makes you look like the real deal :-)

Another thing with that technique : rest the meat long enough. Makes a huge difference (not necessary with sous-vide/low temperature I think)

And contrary to what I've read, good precision cooker and vacuum machine (dunno how to call it in English) can be quite pricey. A few hundreds euro down here, so not cheap at all.

For ~$100, you can get a sous vide machine that attaches to most pots and a set of reusable zipper bags with a valve built in and hand pump for vacuum sealing. I highly recommend trying it out as the steak and fish I have tried cooking so far all come out very tasty and well cooked.

It's not clear to me what they're using for the surface heat transfer coefficient, which I think would be different for a skillet vs sous vide. (Or even, in their case, Side 1 = skillet vs side 2 = air.) But I only have a cursory knowledge of the physics involved.

For the sous vide case, I've tried implementing Douglas Baldwin's model on Observable. It seems to match the "SousVideDash" results, but this is my first foray into solving PDEs, so use with caution.


If anyone here does know the physics / math, I'd like more details on the $\beta$ "geometric factor" that Baldwin uses. I couldn't find mention of it in books and wonder if it is something you derive (say transforming coordinate systems) or something determined experimentally.

Fluid dynamicist here. The $\beta$ notation appears to be a convenient way to write the Laplacian assuming that the temperature is homogeneous in the angular direction. The values are exact for certain coordinate systems.


My go to site when cooking thicker than normal steaks via Sous-vide

With sous-vide, I'm always wondering a little bit about food safety (BPA and friends). Is there any reason to be concerned or is it just FUD?

This link gets into food safety aspects. Sous-vide is technically a pasteurization process in a way. http://www.douglasbaldwin.com/sous-vide.html

I think he meant specifically of "cooking in plastic":


Sous-vide is just amazing isn’t it? I won’t cook steak any other way since I got my circulator. I have never tried the liquid nitrogen though!

I've had a Sous-vide setup for years and will use it for just about everything, except steaks. No matter what I try I cannot get results anywhere near as good as I get with a simple reverse sear.

Oh interesting... I have tried both and had the opposite experience. A steak Sous-vide to rare and then finished on an ultra hot cast iron skillet with oil, butter, fresh herbs comes out better and more consistent than the reverse sear. How long are you leaving your steaks in the water? Are you putting oil, butter, or any aromatics into the sealed bag?

Yep, totally spoiled now. Can’t eat a steak at a restaurant or anyone’s house after sous-vide.

I also have a great marinade that we add to the bag while it cooks. Seriously, it is ridiculous.

May I enquire about this marinade? :-)

Why do you need the site? I played around with the site, and it doesn't look like it makes a difference if you cook it sous-vide for 20 minutes or 2 hours? (I've never cooked anything sous-vide)

Sous vide needs way more than 20 minutes, but you are correct that once it's reached the target internal temp, the time doesn't much matter (beyond going too far).

Typically, about 90 minutes is a good spot for almost all temps with steak, a little more if it's a thick steak.

For tender cuts of meat (like a good steak) it might be true that temperature is what matters. But cooking sous vide for 12-24 hours can turn a tough cut into incredibly tender juicy meat - the connective tissue needs time as well as temperature to break down.

It's quadratic. You need four times longer for a steak that's twice as thick.

I've certainly overcooked more than a few steaks due to cooking too long, not too hot. Also, it seems it sometimes depends on meat quality (not just the cut). Or maybe it was the sear that I tend to overdo.

In a series of highly (un)scientific experiments the 'Sous Vide Everything' youtube channel concluded that you arguably improve the texture by cooking meat longer by sous-vide, but the flavor deteriorates. I reproduced this result at home.


There's definitely a point when the texture starts to get worse, too. IMO it starts before the flavor degrades significantly, though the timing totally depends on the cut of meat and connective tissue.

This model needs density, moisture content, and temperature gradient at initial cook.

Prob a second model for bone-in cuts.

I'm looking for a recipe that maximizes the term Net Meat Score = [(browning+med rare) - (medium+well)] while also enforcing steak=3cm, Rare=0%, Raw=0, Char=0, and steak starting at either 0C or 23C. Note that you have to let the meat rest for 10+ minutes to really let it finish (the default settings cut it off to early).

The best I have gotten under normal conditions is: Net Meat Score of 40, by doing:

Steak starts at 0C, 3:20 @190C , flip, 1:40 @190C. Yields 17% brown, 23% well, 7% medium and 53% med rare.

Chose 190C because olive oil. Interested if anyone has found something better.

Sous vide with no sear maximizes that: 24 hours at 57C on both sides. It yields 100% medium rare.

Fair, but I was looking for a crust :)

I don't know how to model this, but I can pretty much get this using a searzall. sous vide to desired temperature, briefly drop in ice water to lower surface temperature, then hit with a torch in bursts as desired

This is a good recipe. I tried for an hour to beat it but I couldn't. I tried an oven at 100 and then some searing at 175, but I ended up getting too much well-done.

nitrogen free!

3cm Steak starts at 0°C

280°C and 20°C for 0:30

20°C and 280°C for 0:35

60°C and 60°C for 30:00

20°C and 20°C for 3:00

yelds 73% medium rare, 7% medium, 7% well and 13% browned

take it with a grain of salt tho because the simulator does have some ugly quantization effects, for example:

3cm Steak starts at 0°C

280°C and 20°C for 0:30

20°C and 280°C for 0:35

60°C and 60°C for 25:00

20°C and 20°C for 3:00

reducing the oven pass causes the high temperature skillet passes to burn the meat and yelds 7% charred

Would be interesting to see sous vide and torches incorporated into this.

I usually "sous vide" at a lower temp and then finish with a weed burning torch (aka flame thrower). I find using a large and very hot flame is necessary to get that crisp outside without overcooking it. The handheld chef torches don't get enough searing to cooking ratio.

Fat and connective tissue is another factor that makes things interesting. What's the best technique to soften up the fat and connective tissue without denaturing the protein?

My question is how to brown/caramelize meat with only an induction cooktop?

After I put my chicken, I just see all the water come out and the chicken starts boiling in the pan :(

What is the cut? You might be buying brined chicken (salt solution).

If it was previously frozen, and not thawed out this might be the problem.

Maybe you are "crowding" the pan? When you put too much protein in the pan too close together, the meat steams instead of searing. It needs space for the moisture to air out.

Or you might have lots of surface moisture. Based on your scant description, I'm guessing this might be your issue.

Regardless, try this next time:

- line a flat plate with paper towels

- take your protein out of the packaging, and pat dry on all sides with other paper towels

- place protein on the lined plate

- turn over and replace towels after 12 or so hours. to avoid this, and the lining, you can put the protein on a rack with a towel underneath so air can circulate under the meat

- put back in your fridge overnight on lowest shelf, uncovered (fridge is a very dry environment)

- next day, surface should be very dry

- take protein out 45 minutes before cooking it

- super hot pan + high smoke point oil + don't crowd it + dry protein surface == nicely seared

note: super hot + nonstick is toxic. use cast iron, or stainless that works with induction. induction should get hot enough to sear at 500-700 degrees

salted liberally + open rack in the fridge for about a day gives you both dry surface and well seasoned. sometimes called a "dry brine"

Chicken breast diced into cubes, using Rice Bran oil. I will try those tips. My problem sounds like crowding.

Is your pan induction compatible? If the metal has too much nickel it'll cancel out the magnetic field. Put a magnet to the bottom of your pan and if it grips strongly it should work. Also, do not use a teflon-lined pan. Pans with thick bottoms are better because they retain more heat which is then available to transfer into your meat, and with typical ranges will help avoid hot-spots.

Pre-heat your pan. As your pan heats, toss some water droplets into the pan. Once they immediately form beads and roll around the pan like crazy, your pan is hot enough. But don't let it get too much hotter; if the water droplets disappear in <3 seconds, it's too hot. Pat your slightly-chilled or room-temperature chicken dry with paper towels before putting it down; excess water will prevent the sear, pull moisture out, and boil the chicken. And don't crowd the chicken in the pan, or the close proximity of escaping water vapor will steam the chicken. You can also try adding a light coat of oil to the dry chicken.

Dry the meat with paper towels before. Use cast iron or carbon steel, get the empty pan ripping hot, pour some canola oil and it should start smoking. Put your meat in the pan. Dont touch it for a minute.

Guaranteed sear.

You might need a hotter pan with more butter/oil.

It breaks when you switch to Fahrenheit and use the sous vide + liquid nitrogen recipe. It autoconverts -200°C to -328°F which then errors "too low" (for some reason?)

I got the same error

I wonder if it's because "-273 C = 0 kelvin = absolute zero" which was coded as a simple check on the field > -273 without units

Does this work for sous vide and reverse sear? Water's thermal conductivity is 1/10th of iron and much smaller for air(oven).

If you put a thick steak (like 50 cm) it freezes Firefox for like 4 seconds, while Chrome freezes for 1 second. Real world benchmarks :D

Bill: check out the new optimizations I added to our JS engine!

Sally: Yeah, but did you check for regressions in the thick steak benchmark?

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