Pressure Cooked Stock

[scubadoo97]

Thanks KennethT-Great to know. I had not done the skimming so had no idea what the difference would be. All I knew is that I don't skim and the stock is pretty clear. Glad to know there was no difference. Again in my stock making I find a lot of the scum stuck to the bottom and lower sides of the cooker after draining.

[KennethT]

I rinse the bones first and make sure all the organs (kidneys, etc) are scraped out to try to "minimize" the impurities... that would be another experiment - maybe the rinsing isn't even necessary? I certainly won't be able to get to that experiment for QUITE a while - my freezer has no space for it!!

Scuba - there was a lot of scum on the bottom and sides of the pot - but none of this had emulsified into the liquid, which is the important thing... even when I used to skim, there would be plenty of scum still on the bottom and sides of the pot... it's hard to tell if there's more now that I haven't skimmed - I didn't usually pay attention to exactly how much there was in the past.

[technogypsy]

he proteins- at lower temps than caramelization.

Leave a can of condensed milk on the shelf for a few years, then open it- it will be a nice shade of tan. Maillard at room temp- in the presence of moisture.

Scott, is there a reference for that? I thought the discoloration was caused by oxidation of fats? But I'm not a food chemist...I thought by definition Maillards require significant heat too due to the type of denaturation. I understood it to be different than that which occurs at RT althro there is considerable range. However I guess what confuses me is the 10-2 rule. For every 10 C, the rate constant normal changes doubles or halves so a Maillard's reaction that takes 5 minutes at 68 C would be half that rate at 58 C etc. At some point you fall below the activition energy too. (But I do polymers so I might be clueless - however we do a lot of kinetics) Is there a references 'cause I'd like to read more for my own knowledge as I suspect most people don't care? Thank you.

On the main topic, I never skim and I use pressure cookers all the time for fish stock. One big advantage no one mentioned is in my home kitchen without a hood, I can take the pot outside to cool and open it and my house doesn't smell of fish for the next week. I do get every cat in the area coming by, to my standard's delight. The result is as good as Grandmere's was, it doesn't take all day, and the house doesn't stink. I do put a lot of stuff into a cheesecloth bag to keep it together. Lately, we have been using the burner for the turkey frier and doing it all outdoors.

[scott123]

Dulce de leche is produced by maillard browning of the proteins- at lower temps than caramelization.

Leave a can of condensed milk on the shelf for a few years, then open it- it will be a nice shade of tan. Maillard at room temp- in the presence of moisture.

Scott, is there a reference for that? I thought the discoloration was caused by oxidation of fats?

It's just an abstract, but this study delves into the subject further:

http://www3.interscience.wiley.com/journal/119953293/abstract?

The discoloration is definitely not caused by oxidation of fats. Fat oxidized to a brown shade, regardless of the origin, is going to be rancid/inedible. 'Vintage' condensed milk, though, is quite delicious- the same flavor you get if you cooked it over the stove the day you bought it.

As far as skimming goes... It's time for the culinary community to put a nail in it's coffin and expend this energy more productively.

Cosmetically, perhaps skimming produces a clearer stock (I've never checked), but, for the most part, a perfectly clear stock is rarely necessary, and, for those dishes that require clarity, you clarify.

I have tested skimming/not skimming's impact on taste, though, and the results there are 100% conclusive. THERE IS NO DIFFERENCE. It's all psychological. The initial skimmers saw the scum and said to themselves "ew, that looks gross, I should get right of it" and ever since, chefs have been thinking/doing the same thing. The reality, though, is that scum, when allow to simmer back into stock, has no negative impact on taste whatsoever.

I've brought this example up here and elsewhere a few times and I continue to stand by it: Fond. The water in meat, while roasting, draws out all the supposed 'impurities' that come out of meat during stockmaking, and yet, at the end of the day, no chef in their right mind would ever skim fond. Skimming fond would be ludicrous.

So, put it on a placard and raise it in the air. Tell it to your neighbor. Scribble it on the bathroom wall:

DEATH TO SKIMMING!!!!!!

[Paul Kierstead]

I put it on my facebook wall. Is that close enough? DEATH TO SKIMMING!!!!

[David A. Goldfarb]

I skim at the beginning, but as the stock cooks, the layer on top often seems to be just gelatin that has congealed at the surface where the liquid meets the air, and if you stir it back in, it dissolves, so I don't skim that.

I do clarify stock in general, because it's more versatile and ready to use that way, if I'm making a large batch of stock for the freezer as I usually do. Not everything requires a clarified stock, but there isn't any situation where you need cloudy stock and couldn't use clear stock.

[joesan]

If there's one thing that the whole current "MG" inspired type of cooking has done it's make some of us question the old ways of doing things.

I'm not saying that you do or do not need a perfectly clear stock. In some cases that is cosmetically desirable, in others it is not a requirement.

The point is that if we want to make a quicker, fuller flavoured and easier stock the way to do it may be to dump it all in the pressure cooker, save yourself the chore of skimming and have it ready for use in 4-5 hours less than traditional methods.

[Mallet]

Ok, I'm sold. DEATH TO SKIMMING!!

[KennethT]

I do put a lot of stuff into a cheesecloth bag to keep it together.

hmmm... the biggest problem I have in retaining clarity is getting the liquid out once I get down to the level of the bones in the pot. My first several ladels of stock removed off the top of the pot are perfectly clear - like consomme.. when I have to start tipping the pot and/or slightly moving spent bones or removing spent bones, the liquid always gets a little cloudy from stuff that comes off the bones and mixes with the liquid... maybe this stuff would settle out in a little time, but I haven't tried that... but with regards to the quote above, I wonder if I put everything in a big cheesecloth bag, then when finished, just lift out the bag, let the liquid drain out (no squeezing) and the remains should be untainted...

[technogypsy]

I put everything I can into the bag but I still see some sediment. However as I am not as cultured as most here, I don't mind cloudy broth. I guess I could suck the top layers off because they do look clear. It does come out cleared this way that when I just dumped the trash from the frig into the pot and boiled it.

Kevin

[joesan]

KennethT - pour your stock into a large container and let it cool, then put into the fridge overnight. Next day it will have gelled. On the top will be a layer of fat that is easily scooped off since the main body of the stock is now gelled. Clouding sediment in the stock will have fallen to the bottom of the container and can easliy be left behind as you remove the gelled stock from the container into a fresh container. I find that this gives a more than adequately clear stock. Not "consomme at Alain Ducasse" clear but clear enough for most everyday uses.

This is what I do with my everyday stock making and it saves me so much time normally that I don't mind undertaking the extra effort now and again to produce really clear consomme when it's called for on the odd occasion. When I need a really clear consomme I generally employ the egg white raft method but I'd also like to try the gel filtration method at some point also.

[scubadoo97]

Joesan, this is what I do too. It's easier to work with when cold. I use to strain my stock through a colander lined with cheese cloth but have done it with moisten paper towels which works very well to remove fine particles. It also catches a lot of the fat off the top.

[KennethT]

Joesan - interesting - I do something similar, but have always found it a pain to portion the stock when it's cold and gelled - it's a semi-firm gel when it's cold... so I typically scrape the fat off the top when it's cold, then reheat slightly just so that it's liquid, then portion, re-chill and freeze...

[joesan]

Looks like we all do something similar. Personally I don't find the gelled stock too hard to work with but I know what you mean. I just take a large spoon and scoop it into individual containers. If you haven't tried it I'd recommend leaving it in the fridge because all (or much of) the sediment just falls to the bottom and can be left in the bottom of the pan without any straining. It's an added bonus that the flat solidifies as you say. I normally scoop it all straight off with palette knife and selectively add a little in to enrich soups etc.

[joesan]

Some more on the topic from Dave Arnold at Cooking Issues. In precis Pressure Cooking can be better but you need the right pressure cooker. The Kuhn Rikon ones I recommended earlier seem to work well.

[RWells]

Some more on the topic from Dave Arnold at Cooking Issues. In precis Pressure Cooking can be better but you need the right pressure cooker. The Kuhn Rikon ones I recommended earlier seem to work well.

This is an interesting distinction, one that I have personally witnessed. These guys are culinary school instructors who ran an initial test with grandma's jiggler pressure cooker (the one available at the school) vs. the conventional stock method. To their horror the conventional method won. One of the instructors was not convinced and he repeated the test with his home pressure cooker a more modern Spanish made, Fagor model. Blind taste tests bore out his intuition. The more sealed and frankly, safer pressure cooker beat conventional stock.

I have personally used my grandmother's ticking time bomb of a pressure cooker. Scared the crap out of me. I own a more modern Fagor and have been very pleased with its quality and the results. The "pot" of the pressure cooker is one of the best pots I own. High gauge, heavy, an excellent stockpot in it's own rite. The system while obviously not "sealed" is a much more closed system than the weight, "jiggler" models. I have no experience with the Kuhn Rikon models, I hear from colleagues that they are great as well. Fagor is a great company. They are available at Bed, Bath and Beyond. I bought mine with one of their ubiquitous 20% off coupons and it was very affordable. Would make a great Christmas present.

Bob

[vice]

So if one difference between pressure-cooked and conventional stocks is that more volatiles are retained with PC, what does this mean for us home cooks who reduce stock for storage? Does the reduction step negate any advantage? This shouldn't matter so much if the bigger gain is in increased gelatin content or extraction of other compounds.

Edited December 28, 2009 by vice (log)

[paulraphael]

The Cooking Issues post looks like required reading, based on the dramatic results.

Pretty sure, though, that it was the Kuhn Rikon that beat the conventional stock, not the Fagor.

[vice]

Yeah, they were pretty explicit that the KR (spring valve) yielded a better product than the cookers with either a jiggle or a rotating switch valve. As they only had one of each type of cooker, however, the results could be due to other differences between their test models. This gets back to my question above: are their results due to differential extraction or to differential volatile retention? All their cookers reach similar temperatures and pressures which suggests that extraction was probably similar. The big difference was that the KR does not vent steam (and presumably volatiles), whereas the other models do. More testing is needed to get to the bottom of this, and thankfully Dave Arnold indicates that it is on their agenda.

Paul, have you had any luck tracking down other (cheaper) pressure cookers with a spring valve? I'm batting zero.

[paulraphael]

This gets back to my question above: are their results due to differential extraction or to differential volatile retention? All their cookers reach similar temperatures and pressures which suggests that extraction was probably similar. The big difference was that the KR does not vent steam (and presumably volatiles), whereas the other models do. More testing is needed to get to the bottom of this, and thankfully Dave Arnold indicates that it is on their agenda.

Yeah, I think it's their assumption that the other kinds of cookers lose volatiles. Knowing for sure will require a much more elaborate experiment design. I'm sure they're on it!

[OliverB]

this is interesting. I don't mind skimming and simmering for a long time, but with two little ones it can be hard to find a day where there's enough time to be around the house for hours.

With chicken stock I find that there's little scum to deal with. I'm pretty sure I'd skin with veal bones or beef stock though, especially "white" i.e. made from not roasted bones. That scum is really filthy foamy icky stuff that I'd simply not want to ingest, no matter how tasty it may be. Still, seems a pressure cooker would get great results after skimming in a lot less time here too. I guess I'll have to put a KR on my amazon wishlist :-)

[Guy MovingOn]

Reading through this thread, and the post on Cooking Issues (http://www.cookingissues.com/2009/11/22/pressure-cooked-stocks-we-got-schooled/) I have been interested in pressure cooking stock. I understand that the Kuhn Rikon pressure cookers are highly recommended, especially for their spring valve, but I would like to ask if anyone has seen these:

http://www.amazon.co.uk/WMF-Perfect-Pressure-diameter-stainless/dp/B00008XWYR/ref=sr_1_3?ie=UTF8&s=kitchen&qid=1268635892&sr=1-3

I am very tempted to get one, and it seems that according to their features, they might even be better than the Kuhn Rikon ones... Does anyone have any feedback or recommendations based on this?

Also, in this thread, many people were talking about avoding stirring the stock too much to avoid a cloudy stock, etc. If we were to do a gelatin clarification/filtration, would this negate the need to keep the stock exceptionally still during cooking?

Many thanks for the help!!!

[Richard Kilgore]

I don't know anything about the brand, but noticed that this one has a 3 year guarantee vs the K-R's 10 year.

[Patrik Svensson]

I bought the WMF Perfect Plus 8.5L and I'm very happy with it.

My brother have a 4.5l and he's also very happy with his.

I bought mine mainly to be able to make stock "quick and easy" :-)

[Guy MovingOn]

I bought the WMF Perfect Plus 8.5L and I'm very happy with it.

My brother have a 4.5l and he's also very happy with his.

I bought mine mainly to be able to make stock "quick and easy" :-)

The 8.5L one is the exact same one that I was interested in purchasing, since on Amazon it is the same price as the 6.5L one!

I also like the fact that it seems to be extremely easy to clean (dishwasher safe too), and has a universal plate at the bottom to allow it to be used on induction hobs. There are also some good accessories that can go with it, so it can be a multipurpose pot!

Do you find the size of the 8.5L to be too large? I would use it for domestic purposes... but if i could make a large batch of stock at a time, or pressure cook whole joints of meat, that would be pretty cool! Since it is the same price as the 6.5L, i guess bigger is better?

But does it take a very long time to come up to pressure??

Thanks!