Making an authentic French stock/demiglace

[marvelous_marvin]

Hi,

I'm working through "Jacques Pepin's Techniques," and I've just made my second go at making demiglace from scratch. His recipe includes 10 pounds of bones simmered for 10 hours, and after the whole thing is reduced, it's supposed to result in this semisolid gelatinous mass that can be cut with a knife (as shown in a photo in the book).

I can't get my demiglace to form up anything near that solid--the best I can do is a very thick liquid. What am I doing wrong? Is it customary to add arrowroot or cornstarch to make a demiglace of the right consistency?

[Pallee]

No, you never should need any thickener at all.

I don't have his book, so don't know his exact instructions, but here's what I do.

I use veal bones and sometimes veal feet or "trotters" if I can get them. Brown in oven, brown the mirepoix, add some tomato product, peppercorns, thyme and parsley stems, garlic. Cover with cold water, bring to just a boil, skim the scum, and let simmer, never boil, for at least 10 hours, often I go 20. Then strain and defat. This stock gets reduced down quite a bit - check the consistency by spooning some on a plate. I pour it into a shallow pan to cool and firm up, then cut it into brownie size pieces, wrap with saran and freeze to use as needed.

I usually make a second stock, covering the used bones with cold water, adding fresh roasted mirepoix, and cook for another 20 hours, repeating the straining and reducing. This "remouillage" will need more reducing as it's not as strong, but is still useful.

The yield is not huge, you're probably just not reducing it down far enough.

[tim]

Marvin.

If your stock is not solidifying at a little lower than room temperature, I will agree with Palee that you are not reducing enough.

You should review Pepin's recipe to understand the differences. Possibly you had more water added to the ten pounds of bones. Your bones may not be of the same quality, maybe with less collagen. It is also possible that you simmered at a lower rate and didn't get the same extraction. (I also simmer veal for up to 20 hours.) Maybe your stock didn't reduce much during the simmer due to a humid kitchen, narrow stock pot or really slow simmer.

There are a number of variables and you have to learn to judge the concentration of your stock and adjust. If you have not extracted all that your bones have to offer a second run (fresh water with the same bones for 10 hours or more) can yield a wonderful stock. If you didn't get much reduction during the simmer, more reduction after straining may be appropriate.

With time, you will learn to judge a stock by its flavor, clarity and viscosity. I think it helps to pull a half cup of stock out every hour and compare it as you simmer and reduce.

Good luck,

Tim

[marvelous_marvin]

I did notice that in his recipe he calls for 10 pounds of bones (veal, chicken, beef) cut into 2-inch pieces. My butcher winced when I asked for them cut that way, since that is a lot of cutting of big irregular bones into teeny pieces. I think they wound up about 4 inches on average. I mention it because I wonder if the difference in surface area would have made a significant difference. Maybe compensate with more bones?

The stock definitely went down about 1/15 of its original volume

[Busboy]

Are you letting it cool before you see if it's solid? I'm no Jacques Pepin, but I've never made a stock that didn't turn into meaty jello at room temperature and I never even really tried, it just seems to come out that way. Tim's suggestions seem spot on and another to bump up the gelatin is to add a sliced pig's foot or two into the mix -- also adds a little flavor. Thomas Keller does this, (and chicken feet in his chicken stock) so it must be OK.

[Shalmanese]

You said it was a thick liquid so I'm guessing you're actually judging the stock while it's hot. It's meant to be solid when cooled.

[paulraphael]

I did notice that in his recipe he calls for 10 pounds of bones (veal, chicken, beef) cut into 2-inch pieces.  My butcher winced when I asked for them cut that way, since that is a lot of cutting of big irregular bones into teeny pieces. I think they wound up about 4 inches on average.  I mention it because I wonder if the difference in surface area would have made a significant difference.  Maybe compensate with more bones?

The point of small pieces is to get more surface area for browning. With bigger pieces you'll still extract as much flavor from the beef (it simmers a long time!) but the stock will likely be less brown and have less of the roasted flavors you get from browning.

[paulraphael]

You said it was a thick liquid so I'm guessing you're actually judging the stock while it's hot. It's meant to be solid when cooled.

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An easy way to do this is to spoon a bit onto a cool plate. This will give you an idea of its consistency at eating temperatures.

As far as Pepin's recipe, it's very typical of what I hear restaurant cooks doing these days, but it represents a major shortcut (perhaps a shortcut on a shortcut on a shortcut) compared with what traditionally has been called demiglace (which itself is a shortcut, intended to simulate natural jus and coulis which are not possible to prepare in a modern restaurant that needs to make a profit).

I would recommend a look at Sauces by James Peterson, and possibly also The Saucier's Apprentice by Raymond Sokolov or Le Guide Culinaire by Escoffier. These will give an idea of the origins of demiglace and the differences between one and a glace de viande (an important distinction that seems to be getting lost. What you're describing--a 10X or more reduction that results ina a solid mass--is glace de viande, not demiglace. It is used very differently in recipes than demiglace). Peterson especially will give you much more theory than you get from Pepin, so if you chose to take Pepin-like abbreviations, you'll at least have an understanding of what you're doing.

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