Rendering fat caps

[Shalmanese]

When it comes to foods like duck breast, leg of lamb, rack of lamb, rib roasts or pork belly, there is often a thick layer of fat on the outside. This layer can be delicious if cooked correctly, with a thin, crispy, juicy layer of well browned fat that packs a lot of flavor. On the other hand, if cooked incorrectly, it's flabby, greasy and downright unappealing.

What is the best approach to cooking these fat caps for optimum results?

One trick I sometimes use for large, flat pieces of meat with fat only on one side like duck breast or leg of lamb is to leave it uncovered in the fridge for as much as 4 days. The skin side will dry out which increases the amount of fat rendered. One thing I've taken to doing recently is pre-salting the meat which tends to render out even more fat.

Nathan Myrhvold claims to have a novel way of cooking duck breasts which involves using dry ice to cool down the skin beforehand. I've not yet tried it but it seems interesting.

One thing which I've only recently been experimenting with is to continually slash the fat cap during cooking. I always used to score the fat cap before cooking but I've noticed that cooking tends close those pores up and might inhibit the fat from escaping. For my next leg of lamb, I'm going to flip every 30 seconds and recut the fat every time I flip to see if it makes any difference.

Finally, one quick tip for cooking steak. A pair of locking tongs (I prefer OXO) make an excellent impromptu device for keeping the steak upright during cooking of the fat layer:

[Kerry Beal]

Finally, one quick tip for cooking steak. A pair of locking tongs (I prefer OXO) make an excellent impromptu device for keeping the steak upright during cooking of the fat layer:

Brilliant!

[Blether]

A month or so ago, I trimmed the fat from a piece of fillet steak (the biggest part was between the muscles) and rendered it for fat as a base for frying onions and making a sauce to put in a pastry case with it. That gave the sauce a distinct, rich beef-fat flavour (and meant tasty cracklings for me) that I thought was pretty good.

A couple of weeks ago I rendered the fat cap and between-muscle fat from a couple of big pieces of chuck (shoulder clod) for stew, for fat to brown the meat and onions. I put the cracklings back in to the stew with the meat - lots of browning on them, as you say, and the smaller pieces dissolved completely giving body to the stew. I'd left the bigger pieces of fat (like 3" square) as they were - they gave their browning and some body to the stew, but I had to fish out the goo-ey chunks that they left. In future I'd cut all the fat down to the same 1/2" or 3/4" pieces.

Shoulder clod is very lean - I'd definitely do the same again. I'm pleased with the approach, overall - I've got the benefit of fat that otherwise would've been set aside on the plate and thrown away. If you like soft lumps of fat in your stew, it wouldn't make sense.

[Shalmanese]

Rendering and using fat that's been separated from the meat is a completely different discussion. I'm hoping to focus this specifically on the challenges of fat that's surrounding the outsides of a piece of meat.

[MartinH]

Shalmanese, let us know how the flipping and cutting of the leg of lamb goes. Have you tried jaccarding the fat layer? Love the tongs idea.

I'm wondering if the salting, drying, and even dry ice techniques work equally well when the skin is present and covering the fat (as with duck) or not and the fat is exposed (as with meat).

The Chinese are said to render fat from a duck by first steaming it. I'm wondering what the optimal temp is for roasting a whole duck to render the fat. I have tried at the lowish temp of 200F which seems to work OK but I haven't experimented with alternatives.

[Shalmanese]

So tonight, I'm trying drying as a better way of rendering. I've had a boned, rolled leg of lamb which I salted & spice rubbed 3 days ago and that's been sitting uncovered in my fridge until tonight (apologies for the amateurish tying job):

The first thing I noticed when I put it in the pan was that it was virtually noiseless. I'm used to putting leg of lamb in a pan dry and letting the fat naturally render out but this clearly wasn't happening. If anything, after adding some peanut oil, I would say the lamb was sucking up oil. The other thing I noticed was how ridiculously faster it took to brown than an undryed piece of meat. After letting it go for 30 seconds on one side, it was already mid brown and the entire searing of the leg took only maybe 5 or 6 minutes:

The other thing that tripped me up was that the pan "sounded" a lot cooler than it actually was which caused me to burn bits of the meat. There wasn't the sizzle I was used to hearing so I cranked up the heat a little too high.

I think fridge dried meat might have potential with high heat roasting but pan searing is turning out largely to be a bust. I have it in a 425F oven right now so I'll update on the details of how it ends up turning out.

edit: Wow, one other side effect of drying seems to be that the meat cooks MUCH faster. I just went to check on the roast and it's already at 130F. I don't keep track of time but it can't have been more than 30 minutes in the oven. For comparison's sake, I put some roasted cauliflower in the oven right *before* I started searing the lamb and the lamb was done before the cauliflower was. I don't really have a good explanation for how it could have cooked so fast but I confirmed with two different thermometers and the lamb is indeed cooked.

Edited February 10, 2010 by Shalmanese (log)

[stealw]

Very interesting topic; as I was about to start a post of something very similar to this. The past weekend I cooked some pork belly. Scored the top, put it in braising liquid, covered only the lean meat portion with the liquid, and left the fat "naked". Then 325 oven for ~3hours or so (uncovered).

The result..."crispy" skin, very moist and tender lean meat. However, only qualm about this technique is that it resulted with an almost chewy/leathery texture of the skin/fat. (My original plan was to put it under the broiler for a bit and really crisp it up, but I was out and had someone pull it out for me, thus no broiler effect)

Then it dawned on me, could I have possibly cooked the pork belly like a duck breast? Duck breast: score fat-cap, place in cold pan, render, render, render...flip over and cook other side.

Has anyone tried this before? I'd assume it could work, since you can roast a pork belly & duck. Perhaps I may experiment with this in good time. Until then...open for suggestions.

Jim

[Shalmanese]

Another experiment, this time with a pork loin roast. I brined the roast, then poked holes in the fat cap, rubbed it with red curry paste and pressed some paper towels over the fat side to try and draw out some of the moisture.

When it came to cooking, I started it off in a cold pan with another, weighted pan on top of the roast, pressing it down.

The roast is still in the oven but I think this is one of my more successful attempts. The holes vs scoring gave the top of the roast a more attractive appearance. The weight pressing seems to have helped render significantly more fat out. I'll wait until the roast is out of the oven to give a final verdict.

[Chris Amirault]

I'm having a hard time imagining what you did. Did you rub it after putting the curry paste on? Do you have photos?

[Shalmanese]

I'm having a hard time imagining what you did. Did you rub it after putting the curry paste on? Do you have photos?

Sorry, I rubbed red curry paste on all the meat sides of the pork and left the fat side clean, with a towel on top to dry it. Before searing, I scraped off the curry paste and used it in a satay sauce.

The roast was a huge success, the fat cap on the original loin was ~1/2 an inch thick and, at the end of the cooking, it was probably only 1/6th of an inch. I think the pressing was a huge help and something I intend on exploring more.