FOOD PHYSICS. HOW TO COOK MEAT, SCIENTIFICALLY INVESTIGATED

Preparing a piece of meat a piece of cake? Not exactly, according to Harold McGee, Jack McInerney and Alain Harrus, two physicists and a writer on the science of food and cooking.

They published an article in an issue of Physics Today that was dedicated to everyday physics (November 1999): The virtual cook: modeling heat transfer in the kitchen.

Below are the juicy bits from that article and here is the handy download (PDF) that you can stick on your fridge. There is only one more tool that you need to cook meat perfectly.

The tricky part of cooking meat? It is that time when the meat is just right, at just the right temperature, because it lasts only about two minutes. So you do want to invest in that meat thermometer. Meat thermometers are not that expensive. But how do you avoid overcooking the outer parts? The three authors or the article in Physics Today looked into the matter and came up with the following guidelines.

• Use thin cuts.
• Pre-warm the meat, for instance by immersing the (wrapped) meat in warm water, so that its temperature rises to about 40 °C (104 °F). This diminishes overcooking of the outer parts as it reduces the cooking time. Letting the meat warm to room temperature is much less effective! When you try this at home, you may notice that the color of the meat changes. The red color of meat is caused by myoglobin, an oxygen-storing protein. It denatures – breaks down - at higher temperatures and then turns grayish brown. Experiment with this and you may be pleasantly surprised by the results.
• Keep the surface temperature below boiling. This minimizes the temperature gradient across the meat and it maximizes the time interval during which the center of the meat is close to its temperature optimum.
• If you fry or grill meat: Flip the meat frequently. This is much gentler on the meat.
• Do not boil tender meats or fish. Simmering or poaching well below boiling is much better (at about 80 °C or 176 °F).
• Do not stick to standard rules about cooking time per weight or thickness. They have nothing to do with physics and cooking meat is physics, and chemistry. When you have double the thickness of a cut of meat, for instance, the cooking time does not become twice as much but almost four times as much. That's Fourier's Law at work. The rate of heat flow in one dimension is proportional to the square of the thickness.
• Remember the two-minute interval, when the meat is at its best. Most meat is properly done at temperatures between roughly 55 and 70 °C (130 to 160 °F). Most people cook meat to much higher temperatures, but only tough meats should be heated past 70 °C (160 °F). Other meats turn very dry at those high temperatures.
• At 70 °C (160 °F), E. coli is destroyed. Browning, however, may already occur at lower temperatures and therefore is not a great indicator of temperature.

Heat transfer, that is what cooking is all about. Heat transfer comes in three kinds: conduction, convection and radiation. How the heat is transferred depends on whether the meat goes into an oven, a stewpot, a frying pan or a steamer. Heat transfer within the meat itself takes place mainly by conduction, however.

So, in summary, what determines what your steak or hamburger is going to taste like?

• The difference between the temperature of the meat and the temperature of the heating source. It is the reason why heat goes into the meat, just like water flows downstream, not upstream.
• The type of meat. How good it is (its texture, and whether it has inhomogeneities).
• The temperature of everything in your kitchen and the initial temperature of the meat.
• The presence of water, which lowers the effective cooking temperature. Regular meat consists of about 75 weight percent water. If you think that loss of water has something to do with juiciness, you guessed right.
• The heating path. That’s the time a piece of meat spends at a particular temperature. Or in plain English: how quickly or slowly you heat it and the way you turn up or turn down the heat when cooking your meat.

The authors of the article used a computer program called FlexPDE to model their meat problems. You can download the Original Unlimited Scripted Multi-Physics Finite Element Solution Environment for Partial Differential Equations from the web site of PDE Solutions Inc.. Student version available for free.

Physics Today is published by the American Institute of Physics.

Here is the handy download (PDF) that you can stick on your fridge if you didn't already download it. And here is the link to a meat thermometer that will help you cook meat perfectly.

Disclaimer: SmarterScience and Angelina Souren cannot be held liable for the results of any decisions made on the basis of the contents of this web page or of any other pages on this web site.

MYSTERY CLICK:

DOWNLOADS:

How to cook meat (PDF). Next, click on the image below to get a great tool that will help you do it.

How to limit flooding (PDF)

Grain size table (PDF)

---

TAKE-AWAY:

Your only limitation is how much action you are willing to take.

Carrie Wilkerson

---

LIVE CHAT (not answered 24/7):

TWITTER:

The small print:

Yes, of course I cherish your privacy and confidentiality. No, of course I won't send you spam.

My favorite countries:

The United States and Spain.

Science and technology reading material for you:

Looking for something special?