Why do 12-hour 185F short ribs have more gelatin then 72-hour 140F short ribs?

[torolover]

I understand at low temps it takes longer for collagen to turn to gelatin for tough cuts of meat.

 

I've recently compared short ribs cooked for 72 hours at 140F with short ribs cooked for 12 hours at 185F.

 

Why does the 12 hour short ribs still taste like it has more gelatin then the 72 hour short ribs? 

 

I've noticed the same thing with pork belly as well.

 

If I want to convert ALL the collagen into gelatin at 140F, how many hours would it take?

Edited January 9, 2015 by torolover (log)

[Norm Matthews]

This site helps explain what happens when meat cooks.  

 

http://amazingribs.com/tips_and_technique/meat_science.html

 

Here are a couple brief quotes from the site. More collagen is formed at higher temperatures because it doesn't melt very much at lower temperatures. It isn't low temperatures and long cooking, it's slow cooking with lower ambient temperature (190º to 200º vs higher roasting temperatures) to achieve the best gelatin results.

 

"140ºF Connective tissues called collagens begin to contract and squeeze out pink juice from within muscle fibers..."

 

"160-205ºF Tough collagens melt and form luscious tender gelatin.  The process can take hours so low and slow cooking creates the most gelatin...."

Edited January 9, 2015 by Norm Matthews (log)

[Smithy]

Norm, that's a great site. Thanks for the link. I have a question about what you wrote below, however:

More collagen is formed at higher temperatures because it doesn't melt very much at lower temperatures. It isn't low temperatures and long cooking, it's slow cooking with lower ambient temperature (190º to 200º vs higher roasting temperatures) to achieve the best gelatin results.

Did you mean that more gelatin is formed at higher temperatures because collagen doesn't melt much at lower temperatures? Collagen isn't formed at higher temperatures, is it?

[gfweb]

Exactly. Collagen isn't formed during SV, the cow formed it when it was alive. Gelatin is what you get from thermal denaturing of collagen during cooking into a soft gelatinous substance. What was gristle is now juicy stuff.

 

Ultra-long term SV could easily solubilize the gelatin and it might leak out into the bag, thereby having less in the meat. Like the gelatin that comes out of bones in the stock pot

 

Re "140ºF Connective tissues called collagens begin to contract and squeeze out pink juice from within muscle fibers..."  Not sure that's quite right either, I believe that its the muscle fibers themselves(actin and myosin) that contract at ~140F and squeeze out juices...which at 140F probably isn't pink anymore.

[Smithy]

I understand at low temps it takes longer for collagen to turn to gelatin for tough cuts of meat.

 

<snip>

 

If I want to convert ALL the collagen into gelatin at 140F, how many hours would it take?

I think the answer, based on what I've read (including Norm's post) is somewhere between "more than you care to spend" and "infinite". As Norm and his linked article point out, you need a higher 'low' temperature.

gfweb, thanks for confirming my reading. I suspect an early morning typo. :-)

[torolover]

Norm, what a great website!!  Great information!

 

According to Modernist Cuisine collagen can turn to gelatin even at low temperatures of 122F, it just takes a long time.

 

Gfweb, are you saying that gelatin in 140F 72 hours short ribs leak into the bag and doesn't stay in the meat?  Are 185F 12 hours short ribs different?  Those short ribs keep most of the gelatin in the meat?

 

I want to keep the temp at 140F to see if I can keep the moisture of medium rare short rib but still get the same amount of gelatin of a 185F 12 hour short rib.

 

How many hours would it take at 140F to the get the same amount of gelatin as the 185F 12 hour short ribs?

 

72 hours doesn't seem long enough.

Edited January 9, 2015 by torolover (log)

[gfweb]

 

Gfweb, are you saying that gelatin in 140F 72 hours short ribs leak into the bag and doesn't stay in the meat?  Are 185F 12 hours short ribs different?  Those short ribs keep most of the gelatin in the meat?

 

 

I'm saying that the higher and longer you cook, the more gelatin can become soluble and leave the food. Pressure-cooked meat, for example,  often ends up pretty dry if cooked too long in part because the juicy gelatinized collagen is gone from the meat. (The other part leading to dry toughness is the contraction of muscle proteins that squeeze out water which occurs at a lower temp eg the temp of a 'well-done' steak.)

 

I don't know the answer to the specific times and temps for short rib gelatinized collagen, but I was responding to the original question of why a higher temp for a shorter time might more completely convert the collagen.

 

I imagine that there is a sweet spot of time and temp where the collagen is completely gelatinized, but not made soluble, so it stays in the meat.

 

An experiment where  short ribs are cooked at say 140, 160 and 185 and weighed at 1, 2, 3 and 4 days might give an idea at what time and temp the gelatin and moisture begin to leave the meat. The liquid that is in the bag at each time point could be roughly analyzed for gelatin by chilling and looking for gelling. (I'd probably not vacuum pack the rib so as not to remove moisture by vacuum. A zip-loc with a decent seal would be better). Might be fun.

Edited January 9, 2015 by gfweb (log)

[FeChef]

I wouldnt go any longer then 36 hours @ 140F. That, and also making sure you get "true short ribs" I found out that some grocery stores sell a different cut called "chuck short rib" it comes boneless and they market this cut as "boneless short rib" I know it sucks to pay for a bone your going to throw away but its the only way to ensure your getting "real short ribs" I will probably start saving the bones for rich beef stock for making au jus.

[torolover]

I've always wondered about boneless short ribs.  Whenever I sous vide boneless short ribs they are never as good as "true short ribs"

 

 I stopped buying "true short ribs" because after you cut off the excess fat and the bone, you end up with only half the weight.  At $7 a pound (meaning $14 a pound for just the meat) it's too expensive!

[Norm Matthews]

i don't know anything about SV so I can't address those issues but I got some boneless short ribs once last year.  I had never heard of them before so I looked them up and found that they basically were chuck roast cut into strips to look like short ribs.  They didn't taste anything like short ribs to me and I would not ever buy them again. These were cheaper than short ribs but per pound, but expensive for chuck roast.

[btbyrd]

i don't know anything about SV so I can't address those issues but I got some boneless short ribs once last year.  I had never heard of them before so I looked them up and found that they basically were chuck roast cut into strips to look like short ribs.  They didn't taste anything like short ribs to me and I would not ever buy them again. These were cheaper than short ribs but per pound, but expensive for chuck roast.

 

Sounds like false labeling to me. I've run into that problem before; my local market carries real boneless short ribs (as well as bone-in versions) but I ran across a cryovacked package of something that obviously wasn't short rib yet was labeled as such. Maybe what you (and I) came across were those chuck short ribs that FeChef was talking about. I'd never heard of this cut, but found a video about the cut on the YouTubes.

 

 

It's hard to tell without a good closeup, but these chuck "short ribs" don't seem to have anywhere near the marbling or connective tissue of true short ribs.

[Norm Matthews]

In Korean restaurants and when my son and I make Kalbi, we have sometimes cut the meat off of short ribs in a long thin strip, but leave it attached to the bone so one will know what it is.  These didn't look like real short ribs so I googled them and saw that they were chuck.  When I got them out of the package I realized that one (cut into quarters) was not enough for our meal so I went to another store and got a similar sized chuck and cut it myself.  The two looked and tasted alike but the whole one from the other store was about a dollar a pound cheaper. I braised them and they were good but they did not taste like short ribs, in my humble opinion.

 

PS this link shows real short ribs.  One cut they call a flanken sp? cut for Kalbi is what a lot of Koreans call a LA cut (for Los Angeles)

 

 

Korean short ribs, both kinds

 

Edited January 15, 2015 by Norm Matthews (log)

[pbear]

Yes, it's flanken.  From German, by way of Yiddish.