Stock in a Pressure Cooker

[Budge]

There is also the issue that simmering a stock with the lid off supposedly allows for the evaporation of certain undesirable volatiles that would remain behind in covered stock.  Aren't covered stocks supposed to have a "vegetal" taste?

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"...certain undesirable volatiles that would remain behind in covered stock." I think you've hit on something here. Julia Child, in her very first book, Mastering The Art of French Cooking, in her section on making stocks, said (paraphrasing) you would think a pressure cooker would be an ideal means of making stock, but the result is not good. I'm thinking there would be some "yuk" left behind from pressure cooking beef and particularly lamb, perhaps less of that with pressure cooking chicken and perhaps none of that with pressure cooking vegetables for stock.

Edited January 18, 2009 by Budge (log)

[scubadoo97]

I've been using a pressure cooker to make stock for the last 6 months.

I toss in all the chicken parts along with onions and carrots and cook at pressure for 1 hour followed by a slow release. The stock is very flavorful. No vegetal off flavors and the stock is remarkably clear. I find all the scum has coated the bottom of the pot and is a little bit of a pain to remove. The gel factor is fantastic. The bones are intact and crumble between you fingers if squeezed.

It's a winner as far as I'm concerned.

[helenjp]

Scubadoo97's experience is about the same as mine - nice, clear stock. As some people commented upthread, the proportion of fat may be what makes the biggest difference, but I usually include only green onion tops, not round onions (too sweet). No problem with deposits on the bottom, but my current PC (Fissler) has a heavy bottom.

As for temperature, "let 'er rip" is my philosophy! 30-45 minutes at full pressure for a 4.5 liter PC, natural release.

[RedRum]

There is one issues with stock that I do not seem to have been addressed.

cold vs hot water:

Science tells us that you need to start with cold water in order to get the best extraction from the bone marrow. This is because bones have small pores that allow the marrow to be extracted. But they close due to protein coagulation if heated. This is why brown (i.e. roasted bone) stocks are less gelatinous than white ones.

Over the last two years I use a modification of Heston's for stock. I use a pressure cooker pot to brown 1 onion with star anise. I then let the onions cool, then add another onion cut in quarters, and roughly chopped celery, carrot, leek spices, herbs. I add COLD water and the bones, and then bring it to simmer slowly. This gives time for the bones marrow and gelatin to be broken down and extracted. after it reached simmer, I pop the pressure lid and cook it full pressure for 30-40 mins. The best way to tell when the stock is done is when you can snap the bones with your fingers.

This produces a fresher and more vibrant stock than the long simmering one, but with equally good gelification and mouthfeel. It only takes 15 mins more than Heston's stock, but the results are much better.

Edited January 20, 2009 by RedRum (log)

[RedRum]

The problem with using pressure cookers for stock is if you rapidly release the pressure after cooking, the mixture will boil violently until the 250degF is reduced to under 212degF - this will surely homogenize any impurities/fat into the stock...

I actually use a pc to make stocks and broths all the time...  and it is possible to make a remarkably clear stock/broth with it... with consomme clarity...

My steps take a little bit longer, but I think, in the end, the result is worth it - I have never tasted any "vegetal" flavor or other off note that has been described above...  also, i don't blanch or wash the bones prior because I think it leaches out flavor...

What I do is put the bones/meat in the pc with the lid off (white stock uses raw bones/meat, brown stock uses roasted bones/meat)... cover with the total amount of water being used.... I bring to a simmer (lid off) skimming all the way... once it comes to a point where no more impurities (or very little) come off, I add the vegetables/bouquet garni, then the lid and increase the heat so that I get full pressure - once at full pressure, I decrease the heat to maintain a bare simmer inside the pot - you can tell the simmer level by listening to the pot - you can hear how fast it boils... also you can tell sometimes depending on how much steam comes out of the release valve - you want it barely steaming at all, while maintaining full pressure.

Chicken stock I let go this way for 1/2 hour, beef/veal stock I let go for 1 hour.

Then, I turn off the heat and allow the stock to "steep" until cooled enough so that there is no more pressure in the pc...  this takes a few hours - once sufficiently cooled, I remove the lid and strain through a strainer lined with cheesecloth, trying to disturb the bones/meat as little as possible.  I have no bacterial concerns since 1)everything has been killed while at 250degF for 1/2 - 1 hour and nothing has been re-introducted usually around 180degF).

I then cool the strained stock in a sink full of cold water to cool as rapidly as possible, then leave uncovered in the refrigerator overnight... the next day, you can remove the congealed layer of fat from the now "stock jello"...  I'll then reheat and either concentrate for storage, or store in the freezer as is...

I think the key to the clarity is the skimming prior to pressurization, gentle simmering during pressurization, and slow cooling....

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I see this is very similar to the method I use, I do cook it full pressure though. I am using stocks mainly for sauces, not broths so I do not mind the fat rendering in the stock, I actually want it for more flavour. I do agree that this is the best way to make a stock, as it yields better results than long cooking and also improves on heston's method.

[jmolinari]

I don't think i can go back to making stock the old way after this weekend and using a PC. Wow is all i can say.

1.5 hours using KennethT's method and i had a supremely tasty chicken stock, that was better than the one i make cooking in a pot for 12 hours.

Then again, it could be because i used 2 whole chickens for 5 quarts of stock:)

But can't beat the time factor

Only major downside is that my yield was only about 5 quarts of stock..whereas normally i end up with about 20 quarts.

[KennethT]

I don't think i can go back to making stock the old way after this weekend and using a PC. Wow is all i can say.

1.5 hours using KennethT's method and i had a supremely tasty chicken stock, that was better than the one i make cooking in a pot for 12 hours.

Then again, it could be because i used 2 whole chickens for 5 quarts of stock:)

But can't beat the time factor

Only major downside is that my yield was only about 5 quarts of stock..whereas normally i end up with about 20 quarts.

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I agree - the major downside is that my pressure cooker isn't nearly as big as I'd like it to be... but since it's very easy to make and doesn't take much active time, I'd rather do it more often this way than make more at once in the traditional way.

I just wound up finishing my latest batch of chicken stock last night - defatted and portioned... I like to call it clear liquid chicken... out of the refrigerator it was so gelled that I could almost cut it with a knife ... not quite - but it definitely wiggled and jiggled!!

Here's my yield: 17 cups stock from approx. 7# backs and necks, plus about 2# mirepoix simmered at full pressure for about 40 min... yes, it's a pretty measely yield - but I don't have that much freezer space, and my pressure cooker isn't nearly as large as I'd like and haven't had a chance to get another... That came from filling the pc as high as I could - I think I only left about 1.5 inches empty space at the top of the pot - wihch is much less than manufacturer's directions, but I guess it was ok since I didn't have hot liquid chicken magma spewing out of the release valve...

[scubadoo97]

Using a pressure cooker I've gone to making stock on demand. Glad to see others have experienced the concentrated chicken flavor and super gelled stock that so quickly is produced in the pressure cooker.

[jmolinari]

Oh yeah, another item...don't overfill your PC...mine had liquid to about 1" from the top, and i think it was a bit too high...i could tell the liquid was just about touching the pressure release valve.

Next time i'll use, backs, necks and chicken feet, which should take up less space than quartered whole chickens, so hopefully i'll get more stock out of it.

[KennethT]

Oh yeah, another item...don't overfill your PC...mine had liquid to about 1" from the top, and i think it was a bit too high...i could tell the liquid was just about touching the pressure release valve.

Next time i'll use, backs, necks and chicken feet, which should take up less space than quartered whole chickens, so hopefully i'll get more stock out of it.

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The best things to use are necks, backs, wingtips and feet - they have the most connective tissue (which turns into gelatin)... using whole chickens would be great for making a soup or broth, since the meat gives nice flavor... but typically, I like my stock to be more neutral in flavor - so I don't use meat... but to make a broth I like to add wings as my main meat source..

[scubadoo97]

I don't run across feet but save backs, necks, wing tips, hearts and gizzards when breaking down or spatchcocking chickens. Doesn't take long to have bags and bags in the freezer.

[muichoi]

I'm a great believer in the pressure cooker, but not for stock. It always comes out cloudy and gluey.

[scubadoo97]

I'm a great believer in the pressure cooker, but not for stock. It always comes out cloudy and gluey.

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I wonder what the differences are in our technique. It is the opposite results for me. The stock is extremely clear and no hint of gluey.

[Chris Hennes]

I made stock in my pressure cooker (actually a 23qt pressure canner) last week and it turned out very well. I basically followed KennethT's method, using about 10 pounds of bones and 2 pounds of feet, plus two carrots, an onion, and two celery stalks. It turned out very well: not crystal clear, but not any cloudier than my typical stovetop stock. Unfortunately, I had the opposite problem you guys are talking about: my pressure canner is by far the largest pot I own, and I had it 2/3 full: I could not keep all the stock I ended up with for want of containers!

[jmolinari]

Chris, when i make large stock amounts, i then reduce it to about a 5:1 ot 7:1, and freeze it in 4oz. tupperwares, then pop the disks out, and put them in a zip lock bag. You can store the equivalent of 20 quarts of stock in 10-15 disks.

When needed you can cut off chunks while they're still frozen , or take out and put in fridge...

[Stephie]

I made veal stock in my pressure canner today (All American 25 qt) according to MC's instructions. I understood that because of the pressure in the cooker that my stock wouldn't boil. It did. In the first batch, it was obvious because the liquid was dried a good four inches above the level that went in. In the second batch, it hit the lid and was still lightly boiling after depressurization. The stock is fine, other than being far from clear. Any insight as in to what I did wrong?

[patrickamory]

My main use for my pressure cooker is for stock. All my chicken stock is now made in the PC. I usually make Chinese style - just the whole chicken, broken down, some unpeeled ginger and scallions, cooked at high pressure for 45 minutes, slow release.

It's perfect.

[Martin Fisher]

To minimize boiling, use the 15 pound weight and operate the pressure cooker at just below venting.

Depressurize using the natural release method only so the pressure drops slowly.

I'm not yet completely sold on pressure cooker stock.

Does the pressure cooker extract more flavor? Yes, I think so.

Is the flavor of pressure cooker stock better than stock made via other methods? I think that the jury is still out on that one.

I think that the flavor of pressure cooker stock is a bit 'tired' but I'm working to correct that.

[jayt90]

DDFarm, what is natural release?

I let the stock cook at 13 psi for about an hour, with no excess steaming. (13psi is all I can get from a Lagostina, but generally it is quick).

I release pressure just by turning off the heat and waiting, about 15-20 minutes.

If I need to use it right away, I'll de-pressure under a stream of water. That is immediate, and the broth is still reasonably clear.

[Martin Fisher]

DDFarm, what is natural release?

Removing the pressure cooker from the heat source in order to cool down and reduce pressure to slowly and naturally.

Reducing the pressure rapidly via other methods can cause violent boiling.

[jayt90]

I have a feeling certain root vegetables contribute to cloudy stock, and I've had good results with just bones, skin, necks, plus celery. No carrots or other roots. I'm not sure about onions yet.

I would usually have Ruhlman's vegetable stock on hand, and mix it with my all purpose meat and bones stock in making sauce or soup.

Ruhlman has a unique vegetable stock, done in 30 minutes. The fennel bulb he uses is pure inspiration. I think the recipe is ''Ratio".

[nickrey]

If you look at Heston Blumenthal's chicken stock recipe, he does the conventional stock making first step of bringing the elements to the boil and skimming off impurities before pressure cooking the stock for maximum extraction. This is going to result in a more clear product. With the level of flavour extraction done by the pressure cooker, I cut the carrot content way back to avoid both the muddy taste referred to above as well as an orange tint to the stock.

If you are going to use the stock for sauces and to add to other dishes for flavour, why work towards a clearer stock anyway? You could always use an egg white raft to clarify it if you want to use it in a consommé.

[Stephie]

With regards to the natural depressurization and cooling, apparently just letting the pressure return to zero isn't sufficient. That's what I did, and obviously it didn't work out so hot for me. I suppose next time I'll wait another half an hour or so before touching the cooker.

The bigger issue than the cloudiness is that the fat seems to be emulsified in the stock. I went in the fridge this morning expecting to see a layer of fat on top ready for me to remove. Not the case. I have a batch of greasy veal stock and a likely very greasy demi-glace that I just turned off the heat. I can live with it for sauces, but if this was a batch of chicken stock, I'd be more displeased. What I do know is that my next batch will not be 40 quarts!

[rotuts]

that's interesting about the emulsion. after removing the solids, consider re-boiling the liquid and then let that cool. the emulsion then might 'denature' and separate. thats only a guess.

I guess the above is a mistake

i found this:

http://www.google.com/search?client=safari&rls=en&q=breaking+down+fat+emultions+in+stock&ie=UTF-8&oe=UTF-8

one would have to decide if any of the above is helpful

Edited October 24, 2013 by rotuts (log)

[Stephie]

"Well, my theory is that in the case of tonkotsu broth, the gelatin created as the broth cooks acts as a kind of net, trapping all that good stuff and causing the broth to become both opaque, and more flavorful." - Kenji from Serious Eats comments.

Later in his article, he talks about par-cooking the bones and removing the marrow before starting actual stock production. I did par-cook the bones, but a boat load of marrow went in the stock. I used about 70% of bones to 100% water. There is a lot of gelatin in the stock to say the least. If it holds the fat, that could explain some of this.

Interesting find. Thanks!