Beef flat rib sous vide, Two different doneness in the same cut!?

First I'd like to wish you all a happy new year, loads of good think and good food on the table!
I did cook some flat ribs 3 days ago, a 900gr cut vacuumed packed that has been cooked sous vide @ 62C for 48H. Everything seemed to be fine but when I cut the meat I was well surprised to see I had got two completely different doneness in the same cut??? See photo attached:

All I can tell is that the pink part (obviously what I was looking for...) was the one that is between the bone and the first layer of fat, while the overcoooked one was between the top layer of fat and the middle one. I haven't got a picture of my cut (before slicing) but you'll understtand what I mean here:
http://www.todenhammanorfarm.co.uk/shop/images/images_big/flat%20ribs%20raw%202012.jpg
My question is: what may have caused this??
I used the rack to hold the meat in the water bath (I've got a sous vide supreme), could it be the problem?
Cheers
Ben

Find more posts tagged with

Recipes Q's

Comments

Patrick_65747

I to have recently experienced this. I was using the same time/temp you had, and cooked using a polyscience classic unit. I shocked mine afted SV, and rethermalized in a deep fryer. Same deal bottom layer super soft midrare, top layer catfood. i just ended up trimming them all down.

Samuel_68313

I am not really sure but from the photo you've linked to it just appears that part of that cut is lean so it has essentially just dried out and got to the point of being well done.

mipopette

@SamuelG, actually that's what I wondered, but I thought the two massive layers of fat would lubricate it while cooking, preventig it from drying out.

tshewman

With bone-in I would suspec a heat conductivity difference. If I recall ribs outer section is cortical (compact) surrounding spongy (cancellous) bone. This would suggest it's conductivity of heat would be spread out (diffuse) as it would actually both conduct and absorb (making neither a great insulator or heat conductor-gastronomic cross-dresser ;-)). Whereas fat would seem to conduct heat considerably better (this is reinforced by our fats used as cooking mediums-duck fat, oils etc etc). So the meat closer to the bone would be lower in temp whereas further away from the bone be closer to the temp of the bath. How do we work around this is the next question. What I have done a few times with decent success is start at higher temps (e.g. 144 for twelve hours and drop to 128 for the remainder of the 3 days total) with a theoretical (I am extremely hopeful someone from chefsteps will offer some guidance here) goal of beginning to release/breakdown some of the collagen in the bone (soften) without overcooking the outer portions. My theory when I did this was because of the different collagen types and distribution between bone and muscle (of course it would be nice if all the research agreed on this, but alas, not the case). Below is a picture of one of the short ribs using this approach. I suspect cooking boneless would reveal a more consistent result. Am looking forward to more help here as well.

mipopette

I believed after a few hours -let's say 3, though this only depends on the size of the cut- of immersion in the water bath the temperature would be the same and equal throughout the bag, regardless of what's inside. Water being an excellent thermal conductor. I thought that was the whole point with sous vide cooking.

tshewman

As I understand it (am really hoping for help here), the temperature of the water in sous vide creates an environment of relatively equal temperature. However, items in the water would still be required to absorb and deliver/conduct that temperature throughout. If there are systems that absorb and/or conduct differently throughout the same cut of meat (in the rib example), then presumably, the temperature could not be equal throughout unless those conductive components were removed or completely broken down. Those closer to the bone (in the rib example) would then be at different temperatures would then have the potential to be at different temperatures than those distal to the bone. Said another way, if we put on full body long underwear,and stand outside (it's 1deg F where I am right now), different parts of our body are often found to be colder than others. Neuro regulatory systems aside, there are physical/anatomical reasons that also provide influence. Please understand, I am not saying this "is" the way it is. Simply how I am understanding things at this time in the learning process.