Reducing pot roast liquid for beef gravy

You want a thick or thin gravy?

Think stick to you bones stuff you should use a little cornstarch, flour will work in a pinch.

try a little corn starch instead

If you're going to add flour, make a little roux so the flour flavor isn't so raw or uncooked. A browned roux tastes better for roast gravy. I don't make one, but I flour and brown the roast first, which essentially makes a roux. I add a tablespoon of tomato paste concentrate from the tube to the liquid before the roast cooks. I skim the fat and that's it, but I don't like thick gravy. I like it with some body.

Use a cornstarch slurry

If you're wanting a thicker gravy dust that roast good with seasoned flour and brown before adding the liquid. Boom, 3 hours in, badass gravy.