What is the best USDA rated beef best for stew in a pressure cooker?

So, understand that MANY recipes were developed to make poor choices of food products chew and taste much better.

Stew is one of these that allows a tougher cut of meat and some older veg stored in the root cellar to be made tender and tasty.

However, all other things being equal, no matter why a recipe was developed, using the highest quality of meats and veg will always produce a superior product.

So the best beef meat to get for a stew would be prime grade beef, and fresh veg is the best to use for the best flavors and textures.

One more however though. There are diminishing returns on goodness versus price. You don't need prime beef for stew. It will be amazing, but is it worth spending $40 for the beef rather than $20? That's up to you and whether you want to 5 star your stew that was really designed to make halfway inedible stuff decent to eat.

The grades are primarily concerned with the marbling of the meat (http://meat.tamu.edu/beefgrading/). If you use a cut with a high amount of connective tissue (anything from the chuck), then you'll get great results in the pressure cooker even with the select grade.

I should clarify that when you mention the pressure cooker, I'm picturing something like pot roast. If it's more exotic than that, YMMV. :)

There are many factors which go into the grading of beef, simply put it's a measure of overall quality taking into account general condition and appearance as well as marbling. Choice grade is a wide range of beef, there's choice that's almost good as prime and choice that is barely better than select. Select grade meat is really not very good and I would not use it even for stewing.

When choosing meat you want to consider cut and quality. Tough cuts come from the working parts of the animal and have more connective tissue, but more flavor as well. Examples of this are chuck and leg meat, which can be delicious after low and slow cooking provided the quality is good in the first place. Meat from an animal which has been fed poor quality food, not cared for well, and is old is not going to come out tasty no matter how well you cook it.

In general I find that medium grade working cuts give better results than medium grade tender cuts. Going for choice grade is fine if you want to pressure cook, braise or stew - just be sure to shop around and get good choice grade meat as there's a wide variance in quality.

For stewing I have had awesome results using cuts and grades of meat that you would normally consider "chewy", "tough", "stringy" or otherwise undesirable.

The grade, at this point, doesn't matter much. The grades are too varied along the lines your looking for, for a good stew meat. As others have stated, the grades just aren't made for stew meat. There made for shorter cooking times.

So what I look for is "work" parts. Chuck, shoulder, shank, and others that, if fried, would be as tough as shoe leather. I try to find as dense and "stringy" a meat as I can find. There needs to be a little fat, but not as much as a brisket or roast.

Essentially, the more muscular the meat the more flavor it has, but also the tougher it is. The meat softens as you stew it though so it's a great way to use meats that are just to tough for other cooking methods.

What I try to stay away from is "old" meat that should be a better grade but has been "downgraded" because there's not enough fat, or the animal was too old. You want naturally fibrous meat, and not meat that is fibrous because it was past it's time.

Unfortunately, the grades don't lend themselves to this measurement well. I usually end up with something from the select or choice ranges. Again though those are mostly meaningless when you talk about a stew. Prime meats are usually pointless and often detrimental. They may loose their texture and/or flavor before you ever get done stewing them. Nothing is worse then spending $50 on a stew and having it taste worse then a $15 stew.

I just checked my America's Test Kitchen pressure cooker cook book, which I consider the gold standard.

...cuts from the shoulder and boneless shortribs could both work since they have plenty of intramuscular fat and collagen to keep the meat moist. We use shortribs here since they are easy to cut into even size pieces.

When shopping, I wouldn't get hung up on grade. I'd buy short ribs or shoulder meat of any grade.

They also add: even if you trim the ribs well, there will be some fat on the surface of the stwe, use a large spoon to skim it off.