Tuesday, May 5, 2009

Rosemary and garlic grilled leg of lamb, sauteed greens and thermodynamics for the home cook

This is a little belated, and the picture didn't work out so well. But, man, it was something else, and I can't wait to try it again. I guess I'm something of a novelty seeker, and although it's great, I get a little weary of only cooking steak and chicken on the grill. I figured it was Easter, might as well try some lamb.
When I went to Whole Foods, I was looking for boneless leg of lamb. Silly me, they were sold out. I had a choice between previously frozen leg of lamb from New Zealand, or probably previously frozen leg of lamb from a farm in Kentucky, right up the road. Which one was cheaper? You might be surprised to know that the lamb that required a ton more fuel to transport to my "grid" was cheaper. So, Kentucky bone-in lamb leg it was.


Crushed garlic, olive oil, fresh rosemary from the garden, and salt and pepper. Overnight.

Grill temperature: HTH (hotter than hell, more on that later)

Seared the outside, and then set it up on the upper deck with a drip pan to create an indirect effect. The finishing temperature was 126F, and I pulled it off to rest for about 20-30 minutes. With a piece like this, the longer it rests the better.

What does resting do?
I've frequently wondered about this, and what the big deal was. I've ignored it in the past, and didn't think anything about it. According to Cookwise by Shirley Corriher, the outer layer of muscle fiber contract, and that at least partially "squeezes" the liquid to the cooler center of the meat.

You're left with dry outside, wet inside. If you slice you meat too soon, you'll lose a lot of the juices, and the result will be dry. But, if you let the meat rest appropriately, the juice redistributes back throughout the whole cut and is much juicier. Remember osmosis? Fluid moves from an area of high solute concentration to an area of lower concentration. It also moves along pressure gradients. Entropy strikes again.

For my lamb leg, I let it rest almost 30 minutes, and the result was exquisite. The longer the better. Also, serve the juice that runs out as your au jus on the meat at the table; you won't be sorry.

Cooking on the bone
The more I think about it, it really does make more sense to cook meat on the bone. In French cuisine, stock is the basis of many dishes and meat flavors. What is one of the main ingredients in stock? You guessed it: bones. The younger and more cartilaginous, the better. Refer back to JW's post about veal stock based on Ruhlman and Keller's logic of white veal stock being a major contributor to haute cuisine. Veal bones will always make a better stock than beef bones because of their bone/cartilage ratio. Second, there is typically a lot of connective tissue and fat surrounding bone (how the muscles attach to it) which has a basting effect as well as being just plain good, as we know with pork shoulder and other braised/"slow and low". Finally, the bone-in cut also allows for various temperatures of the meat. This can be a challenge with certain cuts (pork and chicken), but with red meats, this is more desirable, and it allows you to taste a range of temperature in the meat. Why is the meat closest to the bone the least cooked, yet the bones are hotter? In other words, when you check the temperature of the meat, if you touch the bones, they will give a falsely elevated reading. Why, then, if the bones are hot, would the meat around the bones not be at a higher temperature as opposed to a lower one? Good question...

Normally, when you cook your meat (boneless) this is how it's going to look. Heat attacks it from the outside via conduction, convection, and radiation and transfers to the coldest area, the middle, thus satisfying the second law of thermodynamics (bear with me). The slower you bring it up to final temperature, the more consistently cooked the entire piece will be. Since the majority of the BBQ cuts we make has a final finishing temperature is around 190-200F, 225-250F is the preferred temperature for cooking it. We can get it to temperature with higher heat, but the outside will be overcooked, and the collagen structure of the meat will not have had time to break down, resulting in something you don't want to eat. Some meats are better suited for slow and low or braising, and some are better on HHH (a nursing term I learned in residency used to describe enemas: high, hot, and helluva lot).

Why do streams always seem cooler than the air temperature would suggest? A phenomenon we can call "heat sink."

Bone-in meat seems to represent muscle with a fluid/flow system within it (the bone). This also has some application in the medical field, if you're familiar with radio frequency ablation of tumors. A probe that generates a bunch of heat basically cooks a tumor, killing it. If you do it close to a big blood vessel, you can't generate as much heat because the continuous current sucks the heat away, acting like a heat sink.
Bones anatomically and physiologically speaking have similar properties to blood vessels, in that they can be used to give fluids and medications. They basically would act like a stream in the middle of a hot field. The part I have yet to prove is that the center of the bones is cooler than the surrounding meat, thus preferentially transferring the heat from the bones centripetally as opposed to the contiguous meat. It may just be that there is "flow" of heat and fluid (gas or liquid) through the center of the bone, and even if the center is hotter, there is a steady fluid flow acting like a convection current that pulls that heat away down the gradient. I guess I have all summer to experiment. I also welcome any better description. I'm doubt JW has gotten any sleep since I posited the question to him.

Back to the menu. The lamb was cooked, rested, looked great and was really juicy. The greens were organic mustard greens that I cut into two inch strips, blanched, drained, and dried. I sauteed some pieces of Spanish chorizo and added the greens back to it for a minute or two. Pancetta, bacon, pork belly, anything fatty would have worked fine. The result was a wonderful main course and blurry picture. Really, though, I can't recommend more highly experimenting with different, maybe unfamiliar cuts. The result could be something really great. I'd feel like I was missing out on something if all I ate was BS (boneless, skinless) chicken breast and hamburgers.

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