Stew meat for something that isn't stew.Can I use stew meat for beef stir fry? Will it be too tough?

I would not use stew meat for stir fry - it'll be chewy even if you slice it thinly. If you do decide to use it in stir fry, definitely slice as thinly as possible (freeze the meat for a short time to make it firmer and easier to slice). You could use a marinade to help tenderize, but be careful. Over tenderizing gives the meat an unpleasant 'mealy' texture.

Use stew meat as is in recipes that call for a long cook/braise. That's what you need to break down tougher meat.

I've used stew meat in stroganoff, kabobbs and one time mistook it for pork rips and it ended up being bbq beef pieces never had trouble with it being too tough but it works really well when u need cut up beef pieces just search for recipes that call for things like Chuck Shoulder, Rump Roast, Pot Roast, ect and it wants it cut up into small pieces works wonders in crock pot recipes

http://nomnompaleo.com/post/22316250352/oven-braised-mexican-beef

http://www.skinnytaste.com/carne-guisada-latin-beef-stew/

Beef barley soup..........or you could sub quinoa (for barley) if you like.

http://www.skinnytaste.com/beef-barley-soup/http://www.skinnytaste.com/beef-barley-soup/

Look into braising, it is a way to break down fattier tougher meats into a nice tender bite. If it were me I would dredge the meat in seasoned flour, then in a hot oiled skillet brown off the meat on all sides, once that is done remove the meat and in the same pan add in tomato paste, and once the tomato paste has browned, pour some red wine into the pan, this is called deglazing and it gets what is known as the fond off the bottom of the pan. That is where the flavor comes from, then add in carrot, celery, and onion. Cook all that together and once the veggies have a little color on them place the meat back in the pan and pour enough stock to cover the veggies and meat. Have your oven heated to about 300 degrees and place the meat and veggie mixture covered with aluminum foil and let the dish bake for a couple hours. Check on the dish throughout cooking and once the meat falls apart when pierced with a fork remove it from the pot. Now the fun part making a pan sauce, remove all the contents of the pot, and pour them through a chinois (a mesh strainer) pouring the liquid into a skillet and reserving the meat and veggies, separate the meat from the vegetables as they are no longer of value and all the nutrients have been cooked out of them, put the meat aside and keep it warm. With the liquid you just saved, turn on the skillet on a medium heat and let the mixture simmer add in some seasonings and a touch of heavy cream, a little more tomato paste, and let the mixture reduce and thicken, finish the sauce with a little butter and viola braised beef, that you can serve with an herbed butter asparagus, or some other vegetables.

If you are in the mood for stir fry, you can slow cook or braise your beef with the flavors to create the sauce for it. Then just stir fry the veggies and add at the end. For me I would braise with lots of onion, garlic and ginger, if you like spicy add red pepper flakes or green peppers; Tamari or Hoisen sauce (or both). Pineapple juice would tenderize the meat faster. For the braising liquid you could just use broth or if you want to go all out a little sake.