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Maximum Collagen Extraction

21K views 30 replies 11 participants last post by  hans.schallenbe 
#1 ·
After simmering my chicken stock for 7 hours I still notice undissolved pieces of soft cartilage. I can squish them between my fingers but they aren't completely dissolved.

Soft cartilage is one of the primary sources for the collagen that makes soup gel, right?

If I want the thickest gel should I simmer it longer?

Also, although I've never seen a recipe adding salt to stock before you simmer it, has anyone ever tried it? In theory the salt should raise the boiling point and the collagen should melt faster. Besides that, I'm not sure what effect the salt would have.
 
#2 ·
It will help if you add some acid, such as white wine, but I don't think you are ever going to melt ALL the collagen. And seven hours on the first boil is more than you need -- 3 to 4 should be plenty; after that, you'll just be releasing more minuscule bits of protein into the water. Strain the stock and defat it. Make a second stock with the bones, etc. (this is remoullage -- reboiling the bones with more water and fresh aromatics), strain and defat that one, then combine the two stocks and reduce them. Reduction gives you a concentrated stock, one that will gel well.

The main reason NOT to add salt to the stock initially is that once you start reducing the stock, you will have no control over the saltiness. I doubt salt would make much difference to the temperature or the collagen extraction.
 
#3 ·
Like Suzanne said, simmer chix stock 3-4 hours tops and taste as you go. Stocks that simmer too long(yup, knew 1 chef who kept his garbage stock going 48hrs plus) will taste "muddy".
Chicken stock i will salt from the start. Something we are all told not to do but it does IMO give your stock a depth you will not acheive by salting at the end. Do not salt if reducing to glace. i do not salt any other stocks, veal, fish, etc...
Reduction is the key to a full bodied stock or sauce without resorting to artificial measures. A split veal foot never hurts either for those meat stocks ;).
Reduce, reduce, reduce.

hth, danny
 
#4 ·
i am curently taking a class called soups stocks and sauces. textbook method of making stocks for us (which has yet to be proven wrong) says to boil for 1 hr and simmer for about 8 - overnight. we never add salt to our stocks because we use it in our sauce production and we dont want to have a salty flavor to start with. as dano1 said if you boil the stock for to long you will have a funny taste to it and it will also be cloudy. our teacher Chef Rerez has told us that it is ok to not disolve all of the connective tissue (collagen) as long as the stock is simmered long enough little bits dont hurt. reboiling the bines and adding that "weak stock" (after draining the bones and bits and peices) will also help to change every last little bit of collagen into gelatin. and be sure to skim the fat. like i said before we do this every class and we havent had any trouble with it at all.
 
#5 ·
From what I'm hearing, it sounds as though stockmaking is about body versus flavor. The longer you simmer the more collagen (body) you get but the flavor gets muddied. So you end up with a compromise - long enough to get a good amount of collagen but short enough to keep the flavor intact.

If one were to have a lot of time on their hands couldn't a better stock be made by separating the soft cartilage from the other bones and simmering them separately - the flavorless cartilage for a very long time and the flavor giving ingredients for only a couple of hours?
 
#6 ·
Scott, whatever you do,DO NOT BOILyour stock for an hour, unless it has been passed and you wish to reduce to demi, glace, or sauce. You WILL cloud it and find the taste unappetizing.
You do need the bits of flesh on the bones to give your stock flavor- along with mirepoix, sachet. The body is controlled by reduction after the initial stock is made-unless its fish or shellfish based. Reduction of these will increase flavor but there just isn't enough collegen there to tighten.
If you want to boil bones for collegen, your stock will taste like boiled bones ;)-not very appetizing. One thing you can do to "fortify" the flavor of your stock is to make what used to be called a second stock or broth(not remoullaige). What this is are meat trimmings and more mirepoix added to a stock for more depth of flavor. The meat has only so much to give before becoming tired. Think along the lines of consomme here.
One thing to remember, and this appears to get lost nowdays, is that stock is just a vehicle, whether it be for soups or sauces. The "demi" this and "reduction" that abounds now on menus shows to me someone who has not grasped the concept of basic saucemaking. Ok enough of my rant :).

hth, danny

p.s. ohh always skim as your stock comes up. The proteins are good for beer but not stocks.
l
 
#7 ·
three hours is plenty of time to release all of the collagen in your chicken as long as its well quartered. for max colagen release, start your stock in a pot of ice water, the slower you bring it up to a simmer, the more time you have for all the good stuff to release from the chix. start slow, once u simmer, keep it on a slow roll. then u have the option of a remulage( never have the time for that myself- i only use this method when dealing with veal or larger bones) strain, shinois and reduce till your hearts content. chicken glace de viande is a beautiful thing with some fresh herbs and a little butter mounted in.
 
#8 ·
I think you might have misunderstood me. Soft cartilage, as far as I know, has no flavor. The bones would be included in the short term (2 hours) flavor-producing pot. The soft cartilage would go in the long term (8 hours) body-producing pot.

Although I appreciate everyone's kind advice, I think I should be clear that I have no intention of simmering my stocks for less than 7 hours. My initial question was as to whether or not to simmer it for longer, not shorter. I adore cloudy stocks. My goal is not clearer stocks but maximum collagen extraction.
 
#9 ·
Okay, Scott, we got you. I'm not sure I understand why you don't mind that your stocks are cloudy, but if that's all right with you, so be it. Really, though, 7 hours is excessive for chicken. Just once, try it our way: simmer 3 hours, strain and make a second stock with fresh cold water and the bones, then combine the two stocks and reduce them.

Here's why: I believe that what you're looking for has nothing to do with time, but everything to do with saturation. That is, the water may have absorbed as much of the protein of the collagen as it can hold; longer cooking will have no effect because the water cannot accept any more protein. That's why we make the "second stock" -- to allow more of the collagen protein to be absorbed into the new water. Then by combining the two stocks and reducing them, we evaporate out the extra water and keep the dissolved proteins.

So you see, it makes much more sense to make two stocks, combine them and reduce them. However, if you are dead set on cooking your chix stock that long: remember that it is possible to burn your stock by overcooking it. The stuff that sinks to the bottom of the pot can burn on, and the film that collects around the sides as the stock reduces can burn. These will give your stock an off-taste. Are you transferring everything to smaller stockpots during the simmering marathon? You should, and you certainly should whenever you reduce stocks.

If you want to experiment with removing the cartilage and boiling it separately, I'd be very interested to hear what happens. Please do let us know how that works, how the end products compare in taste, and all that other good information. (Of course, you could probably get the same effect by adding some commercial gelatin to your stock, but that would be cheating. ;) )
 
#10 ·
Maybe I'm in the minority here, but I've always believed that stocks should be cloudy/hearty and broths clear/delicate.

I've thought about that *S* Is unflavored gelatin really flavorless? If it isn't, I'd hate something that would alter the flavor of my stock. I guess the only way of knowing if it's flavorless is to make some up and taste it.

The idea of the stock being too saturated to accept any more protein is certainly an interesting one. I have to admit that I do a sort of quick second stock just to rinse out the post strained bones. I could shorten the time on my first stock and lengthen the time on my second. My only concern is that, if the remoulage is simmered for an hour or more I would definitely want to chill the first stock during that time.

Suzanne, how long do you simmer your remoullage? Do you chill your first stock while your remoulage is simmering?
 
#13 ·
Gelatin sheets are pretty much flavorless. I can't say the same for granulated stuff like Knox; that has a vile taste, IMO. But unless your stock is really delicate, it might not be noticeable. It also depends on what you're going to use the stock for. If it will be the basis for a soup, and you just want the gelatin for body, the flavor change might not matter. If you want to use it for jellied consomme, though, you don't want to use a gelatin that imparts any flavor. If it's for aspic, well then you need to clarify your stock anyway as well as add gelatin.

I usually simmer the second boil for about half the time of the first (at least, for chix). And yes, I chill the first during that period for a couple of reasons:
1. safety
2. ease of de-fatting, because I don't always manage to skim off all the fat as it's simmering.
Then I combine the two and reduce the whole thing.
 
#14 ·
Why wouldn't you just start the first batch on its reductive way while you simmer the second, then combine during the reduction? Doesn't seem worth the time or effort to chill if you can reduce away some of the extra liquid. Unless, I suppose, for defatting?

I'm no pro.

Phil
 
#15 ·
i have to agree with suzanne on the cooling of a stock. i find that although it does take alot more time than skimming it allows you to remove more of the fat while maximizing the amount of stock you are left with.

as far as gelatin is concerned again i have to agree with suzanne. the sheets have little if any flavor and the powder is NASTY tasting.

i just made chicken stock today and i contemplated this thread while i was doing it. i thought of how you had said you wanted to maximize the collagen extraction. as i was cooling the stock for storage i noticed that it geled nicely. there was no additional gelatin added. just chicken bones (roasted, and the pan deglazed with remoulage), white meripoix, boquet garni, and enough water to cover.

not to sound like a smart alleck but how close to straight gelatin are you looking for?
 
#16 ·
The heads up on powdered gelatin is extremely helpful - thanks.

Chicken stock is the center of my universe. I spend hours making it and by the time it's reduced I have a relatively small amount. Because I start with roasted bones I always have more then enough flavor. If I can get more collagen, I won't have to reduce it as much and then I'll get more stock. The more stock I can get out of one batch means the less frequently I'll have to make it.
 
#17 ·
"I spend hours making it and by the time it's reduced I have a relatively small amount."

again not to be smart or anything but i thought that a stock reduced to that point was called a glace. in that case you are talking about a different beast than just chicken stock.
 
#18 ·
Chef from va, when I say a "relatively small amount", I'm not referring to a glace, it's just a stock reduced to a point where it will gel when cold. I mean "relatively" in terms of a. in relation to the amount of time I put into it and b. in relation to my chicken stock needs.

My needs are such that I have to make stock about every two days. If I can up the amount of extracted collagen, I can decrease that to every three days. Which would be wonderful.
 
#19 ·
scott,
might be best to find a butcher or meat purveyor and buy 40lb cases of chix bones at a time and a 40qt stock pot.
IMO, stock doesn't need much attention-the less its messed with the better. Its set and forget. I don't want to sound like a d..khead but maybe your putting too much thought into this?
40lb chix bones yields me 5-6gal stock that will gel when cooled(not that is my main point).
You can always try a pressure cooker for it ;_.
hth, danny
 
#20 ·
Danny, you're brilliant!! :bounce: PRESSURE COOKER!!!!! Of course! I didn't think of it because I hardly ever use mine -- but I have used it for stock, and it does indeed work very well, and very fast. The only drawback is that it doesn't make more than a few quarts at a time.

Scott, what kind of quantities do you use? And what storage space do you have? Really, the more hard numbers we have from you, the more we can focus. :D
 
#21 ·
How long do you pressure cook it for?

Simmering doesn't need any attention, but by the time you add up the washing of the chicken, the roasting (yes, I'm one of the ones who prefers browning first), deglazing the pan, deboning the meat, straining, simmering again, straining, reducing, skimming, and cooling, it can get pretty labor intensive.

Buying chicken bones sounds like a good idea. Although my local butcher is not that clean, hopefully I can find a butcher who is.

Suzanne, I use about a quart of stock per day. My storage is less of a limitation than my capacity for chicken meat. 2 chickens (about 9 lbs.) gives me about a half gallon of stock. If I roast more chickens I end up with too much meat to work with. Which is why chicken bones sounds like a good idea.
 
#22 ·
Every restaurant I ever worked in used mostly just bones. That might be your best way to go.

Here's a suggestion: since you can't use a whole 40-pound case of bones at once, maybe the butcher you find can keep them for you and you can get them in batches. I hate to say the "f word" but maybe the butcher can freeze ;) the batches, so they'll keep until you're ready for them.

Another suggestion: if not bones, why not use only wings? They should be a lot cheaper than whole chickens (that's what you've been using??? :eek: ), readily available, and with all those joints they've got lots of collagen. I use wings when I make turkey stock, and I get a really good strong broth.

(I haven't addressed your pressure cooker question because I don't know; as I said, I don't use mine very much. But surely someone else knows. Anyone??? :confused: )
 
#23 ·
There's a recipe in the Balthazar cookbook for a jus made strictly with chicken wings that sounds succulent. I have yet to decide whether or not to have chicken wings as one of my manly snacks for the Super Bowl tomorrow. We live a couple of towns away from Gillette Stadium and this is real bluecollar Patriots fan country. I'm not a rabid fan, but after following the Red Sox for a long time, one yearns for championships and real men, not wimps (25 players, 25 cabs) and excuses.

I just got the Time-Life The Good Cook book on Pates, Terrines and Galantines and it shows putting powdered gelatin into a fish stock. Most of the other stocks they have in there are made with either pig's feets or veal knuckles.
 
#24 ·
Oh, yeah: I've been adding a half a pig's foot to my stocks lately (I just make a few quarts at a time at home). That adds a lot of natural gelatin. But some folks can't do that, if they keep kosher or halal. If Scott doesn't have those restrictions, that would work for him, since the richer flavor of the brown chix stock would cover any residual pig-foot flavor.
 
#25 ·
Thanks everyone for all the great advice.

I will definitely seek out chicken bones. I've been paying close attention to wing prices (turkey and chicken) and I can't seem to get any good deals. Also, my favorite brands of chicken don't seem to sell the wings by themselves. I have made stock from wings before and yes, they appear to produce more collagen than any other part of the bird.

I don't keep kosher, but I'm pretty sure I could still detect the taste of pigs feet in my brown chix stock. Pigs feet chix stock are probably delicious, it's just I'm a bit of a purist when it comes to my chicken stock. When I do a pork stock, which I do very infrequently, I'll remember your note about the feet, thanks.
 
#26 ·
Just wanted to add an update, although re: veal stock, not chicken.

Last night I roasted a piece of veal breast, three ribs' worth. As you know, there is not a lot of meat on that cut, but there is a LOT of bone, cartilage, fat, and integument. After dinner, I took all that stuff we'd trimmed off and tossed it in the slow-cooker with the leftover jus, some veg stock, and water, and left it on LOW. It cooked all night at a very low simmer. By the time I looked at it this morning (about 9am), the collagen was mostly melted, and by now (2 1/2 hours later) it is almost all gone. I'm going to have some nice jelly. :lips:
 
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