Beef Vegetable Soup - why didn't the fat render from the brisket?

[greygarious]

I had some sliced BBQ beef brisket in the freezer, from a take-out order a couple of weeks ago. I was disappointed with the brisket that day - not enough flavor other than smoke, with thicker lines of fat than typical. I thawed it in the fridge and today used it to make soup. Figuring that "fat is flavor" and that it would render out during cooking, to be skimmed from the cooled finished soup if the amount was excessive, I sliced the cooked brisket into quarter-inch slices, crosswise and against the grain. I added it to browning onions in the stockpot, stirred it for a few minutes until it sizzled, then added a 28oz can of crushed tomatoes, 2 cans of water, Better than Bouillon, garlic powder, uncooked barley, dried onion, dried bell pepper, dried celery leaves, dried mushrooms, fresh carrots,
and some teriyaki cooking sauce (Mr. Yoshida's). I simmered the bubbling soup for an hour. Everything else was properly cooked, but the fat was still on the ends of the batons of brisket, which surprised me.
Is there anything about the BBQ process that hindered the rendering of the beef fat? .

[Karl S]

You don't render fat at that sub-boiling point simmer temperature (some of the water in the brisket might steam out, but the fat itself doesn't really render) - fat is rendered at temperatures higher than water's boiling point.

[greygarious]

Actually, I am guilty of using "simmer" to mean a bubbling low boil. In other words, the covered pot was at a fairly active perk, but less than a rolling boil. I can fry bacon at the same heat setting - of course in that case it's dry heat.

[Karl S]

The heat of the pan in direct contact with the bacon is hotter than boiling point once the water in the bacon has steamed off. The thermal quality of a large pot full of watery liquid is different. When I render fatty meat, I put about of quarter cup of water to steam the water out of the fat under a cover, but then I have to remove the cover and let all the water vapor out and let the temperature rise over the boiling point (of water) so the fat will render properly. I find, by contrast, when poaching chicken that the fat (which is easier to render than lard/suet fat) not rendered too much - a bit, but not too much (the fat is softer, to be sure, but it's not really rendered).

[greygarious]

Good point about the chicken fat. Fortunately there's not a humongous amount of fat on the brisket. Bottom line is that the soup is better than the plain brisket, at least! :-)

[Madrid]

I just made a porchetta, long roasted pork shoudler, 6 plus hours. It still had wide visible bands of fat after pouring off all the roasting fat. I looked at lots of recipes and then used the Tartine Bread idea of "browning" the sliced slow roasted pork with no added fat. It turned out great...lots of rendered fat in the high heat skillet and crispy pork slices. So I think browning your brisket over high heat with the onions and no added fat till crisp, might have worked before putting it in the soup. It takes high heat to get off the last of that fat!