Doug said:I'm doing a Pork Loin-Top Loin Roast Boneless (rolled & tied). It's 4
pounds. It's about 4 inches in diameter.
Most recipes call for 20 minutes a pound at 325/350.
My recipe calls for 45 minutes at 425. I don't think this is long
enough. Is it?
Not so much not long enough, it's too hot.
I don't think there is any such pork cut as "Loin-Top Loin Roast
Boneless"... you made that up.
Pork top loin refers to center cut loin chops, which of course includes
the bone, otherwise they'd not be chops.
To roast a pork loin use a meat thermometer, do not cook relying on
time... 325ºF is too low, it'll dry out before it's cooked through...
roast pork loin at 375ºF. Most folks cook pork too low/slow, then
blame their inability to cook on the pork not containing enough fat...
stop blaming and learn how to cook. Unlike beef roasts, pork roasts do
better when placed into the oven while fully cold from the fridge.
With pork roasts I prefer checking periodically with an in-sta read
thermometer than relying on a meat thermometer alone. Your roast
should require about 1 hr 45 mins, but check with that thermometer,
every oven is different.
http://www.foodsubs.com/MeatPorkLoin.html