Today was mostly lecture - we learned about beef and had a lecture about kosher animals and kosher slaughter.
Beef is very nutritious - high in protein, many vitamins and minerals, both trace and iron. It also has 5% fat, and the best beef, Prime? Is also the most marbled. Most beef in the US is corn-fed, which to many tastes better, and is more tender, and also has more marbling (marbling is intramuscular fat. There is also subcutaneous fat, which is below the skin. Not as desirable.)
In terms of animals, we get beef from steers - castrated male cattle 9-17 months old. This produces the finest meat. There are also heifers - cows who have not yet given birth, cows and bulls. The latter two are used for pet food and commercial products (soup, McDonalds, etc.) Heifers are mostly used for veal - veal, unlike beef cattle, are products of the dairy industry. Farmers need to breed their cows to get milk, and that will result in calves. These are killed as veal at 250-400lbs. Over 400lbs, sold as "calf meat."
There are seven primal cuts from each side of a steer, after the animal has been cut into quarters. In the kosher world, we only use the forequarters because there's a nerve called the gid hanasheh (the sciatic nerve) which must be removed from the hindquarters in a process called treiboring. This is not done in most of the world (although it IS done in Israel.) As a consequence, we can't use that part of the animal, and it's sold to nonJews. This means we do not use the tenderest part of the steer - the loin and sirloin. No filet mignon, no chateaubriand. No tenderloin. Anything from the thirteenth rib inclusive is not used. What do we use? We use the chuck (or shoulder), the breast and foreshank, the ribs and the plate. So while we do have prime ribs, we basically get the tougher cuts and need to use a lot more moist heat or mechanical means of tenderizing, such as pounding, papain or cubing.
We also had a lecture on kashrut by Rabbi Blech. In this case, it was about kosher slaughter and identification of kosher animals, and information about kashering meat. Kosher slaughter is a tricky subject, where they have to balance the needs of halacha, the needs of the animal and the needs of the consumer (and the safety of the shochet) plus the laws of the land.
It's easy enough to identify kosher mammals - do they chew their cud? Are their hooves split? KOSHER! Although, if there isn't a tradition of eating such animals (American bison, Zabu cattle), it might be problematic. Tradition is important, after all. It's a thing to fall back on if there is doubt. There are also ways of determining kosher birds and fish, including tradition - again, best method.
The most fascinating part from my point of view was the discussion of kashering - meat needs to be salted and soaked within 72 hours, or it needs to be broiled. (Interesting point - one can salt and soak any size piece of meat. Once it's done, it's done. So one can kasher a quarter of beef and then dry age it. More about that later.) If one broils meat over 72 hours old, one can't recook it. Liver MUST be broiled. These days, kashering is part of processing, so it happens before the meat leaves the slaughterhouse, but in the old days, meat was sold unkashered. It would have to be washed every 72 hours unless it were frozen solid (not everyone accepted that freezing solid stopped time). (These days, one can buy broiled liver, too.)
When the rav left, the chef continued. We talked about dry-aging beef - this is a controlled, well, rot. It's done in aging rooms - very low humidity, 34°F, with UV light and constantly moving air to control the bacteria, for up to 90 days. The result is drier, more tender meat with a more concentrated flavor. It's not to everyone's taste. There will be a black, dry crust to be removed.
There is also fast-aged, which is 6-8 days, done at 38-39°F, and wet or vacuum aged (still-warm meat packed in cryo-vac packages.) This last is how most meat is aged.
We also talked about how meat is graded - color (you want bright red or purple) and fat content (more marbling, the higher the grade.) Prime is the most scarce, most high-end restaurants sell Choice. We get Good or Select. There are five grades, with the lowest called "canning." Think Campbell's soup.
And then we got to practicalities. Chef took out a shoulder of beef *and* a pair of cryo-vac packaged minute steaks. He took a boning knife and began to take it apart, going along the muscle lines. Here's the thing - kosher butchers have different cuts and names for those cuts, and anyway, they're not popular among those who don't need to eat them. (This process is called fabrication.)
Once he had the big blocks of muscles dissected apart (using his hands as often as his knife), he showed us how to trim fat and silverskin, and passed out portions. I got a "london broil" - a piece of meat with mostly parallel grain that, with marination, could be cooked in a broiler. First, I weighed it, then I trimmed it. Silverskin is a material that doesn't cook more tender. It has to be removed. It's done in strips, using hands and the boning knife. He said I did a good job, although I think I did butcher it a bit. Then I wrapped it in parchment paper, plastic wrap and aluminum foil, and labeled it.
All meat scraps, btw, were saved for stock, and tougher muscles for ground beef.
The cryo-vacced minute steaks were weighed in the package and then out of it - 4 oz difference. After they were trimmed and the fat removed and the muscles taken apart, with the tender ones set aside from the tougher ones. And the end result? From $7/lb, it went to about $13/lb for the servable parts.
One has to balance so many things - time and labor vs. cost of fabricated meat. And this is important to know.