How to know the doneness for a tough cut of meat

There are two basic cooking methods for tough cuts:

• Cook for a long time ("low and slow"): this is appropriate for large pieces like roasts
• Sear very quickly on both sides and remove while barely medium-rare: this is appropriate for thin steaks

The thing is, while many people mention the second method, it's still going to produce a relatively tough piece of meat. Some people claim that you could take a piece of chuck steak or round steak and make it as tender as a ribeye as long as you cook it fast and don't overcook it. That's just not true, but it's a way of cooking the meat fast, while minimizing the amount of toughness that occurs with fast cooking.

Usually you'd want to do this either with very thin steaks (which is one the reasons flank is often sliced very thin) or with the type of meat that you'd slice into thin strips before serving. Many people cook a traditional "London Broil" this way (which tends to be a relatively lean and somewhat tough cut): very fast cooking on both sides, then slice thinly and serve.

The reason for these two conflicting pieces of advice is that "tough" meat reaches its maximum toughness when it's just "well-done." You generally want to cook it to medium-rare, because that's when beef is juiciest, so you get juice and still less tough. But once you go beyond medium-rare, it just gets tougher and less juicy. At that point, the way forward is to continue to cook for a long time, which will eventually break down the tissues that make the meat tough (as you note), so you'll end up with thoroughly cooked but more tender meat in the end.

The culprit for "chew-y" is all the connective tissues; ligaments, tendons, silver skin, collagen. These need lots of time or very high heat (usually both) to break down into something edible. By the time the meat breaks down to this level you have also cooked every bit of flavor and moisture right out of the meat. This is why lots of BBQ sauce is needed for brisket.

If you cook these tougher cuts to medium rare; then you need to thin slice against the muscle fiber as the above post mentions. Great flavor; but VERY chewey.

Now if you want both; what do you? Besides spitting out 200 bucks for a rib roast instead...

The real answer is Sous Vide cooking; as they are now finally affordable for home kitchens.

Before we were left to smoking; as that was the nearest we could get to precision cooking at lower temperatures over extended periods.

http://www.amazon.com/Anova-Culinary-Bluetooth-Precision-Cooker/dp/B00UKPBXM4/ref=sr_1_1?ie=UTF8&qid=1449120337&sr=8-1&keywords=sous+vide

Fairly affordable and you can do a water bath precision cooking for days.

My current experiments for beef brisket; I water-bath at 131 Degrees for 72 hours; then sear in the oven for 30 mins;

This gives a perfect medium rare that is as tender and flavorful as a filet Mignon.

In your question, it seems like you have large pieces of meat in mind. There are alternative cooking techniques for preserving tenderness, though this often involves changing the meat significantly from monolithic pieces. For flank steak, for example:

1. Slice meat thinly across the grain. Muscle fibers contract as you heat them; slicing across the grain means the fibers will contract in the thin dimension of the meat instead of shriveling.
2. Marinate in sauce with acid, like lemon juice.

There are other techniques too:

1. Salting/Brining
2. Pounding
3. Grinding (chuck which often gets tough, is often used for hamburger)