My question, tonight I used corn starch to thicken. Really didn't get as thick as I wanted. Would a butter / flour rou been better?
Thanks
No, roux will NOT thicken better than corn starch. If it wasn't thick enough then you needed to add a little more cornstarch.
Corn starch is a lot more efficient at thickening than flour, because it's pure starch, whereas flour also contains protein.
Both roux and corn starch have their place as thickeners, and it depends on what you want.
Roux can give a more velvety texture to hot items such as gravy, because it's utilizing fat to coat the starch molecules. But, because of the fat, roux is harder to digest for some folks (especially if using butter or beef fat).
Corn starch will give a more gelatinous texture, especially as the gravy cools, but is easier to digest.
Hope this makes sense.
P.S. Freezing your bone broth for later use was a GREAT idea!