How Long To Cook A 20 Lb Pork Roast

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This method for roast pork gets you meat that's juicy and tender on the inside but with a nice brown crust on the outside. It works perfectly every time!

My favorite way to roast prime rib uses the reverse sear method from Serious Eats.com. To do the reverse sear, you cook the roast at a low temperature in the oven until it gets to the temperature you like. Then you let it rest for awhile. Then you put it into a really hot oven to get a nice brown crust.

It might seem counter-intuitive if you're used to searing your roast before cooking it. But I promise, it works amazingly well. So well that I've applied it to pork roast with the most amazing and perfect results. This is the only way that I roast pork now. The reverse sear is also my new favorite way to cook steaks. I'm pretty excited about it all!

So, today I'm showing you how to apply this same reverse-sear technique to roasting pork. You get a soft juicy inside (nearly as soft as pulled pork) and all kinds of good crunchy meat and fat on the outside.

Here's A Video Showing How To Roast Pork Using The Reverse Sear

How To Roast Pork Perfectly

This how-to is for pork roasts that have some marbling. Look for a pork butt or a pork shoulder (boneless or with bone). Don't try it with a loin. Just don't.

If you have a pork loin instead of a butt or shoulder, go here for instructions for roasting it perfectly.

Getting Your Pork Roast Ready For Roasting

1) Take your pork roast out of the fridge and let it sit at room temperature for 30 minutes to an hour. Preheat the oven temperature to 300°F.

2) If your pork roast has a thick layer of fat on the outside, cut all but a thin layer away so that it's a thinner coating.

Tip: Don't throw this fat out. Season it lightly with salt and then put it in a single layer in a cake pan (something with edges because a lot of hot fatty liquid is going to come out of it). Roast it in the 300°F oven until some fat is rendered. Drain off the fat and keep roasting until very crispy. Check it every 30 minutes or so. When it's crisp and lightly browned blot it on some paper towel and then break it into pieces. Try hard not to eat it all yourself.

3) In a small bowl mix together 1 teaspoon salt, 1 and 1/2 teaspoons of pepper, and 1 and 1/2 teaspoons of garlic powder. That's the right amount for a 5 lb. roast. If your roast is bigger or smaller, adjust the amounts accordingly. Sprinkle the seasoning mixture all over your roast.

Cooking The Pork Roast On Low Heat

4) Put the roast in a large roasting pan, fat-side-up. Add about a half inch of low or no-salt-added chicken broth to the bottom of the pan. Roast it uncovered.

How Long Do You Roast The Pork For?

You're not aiming for a medium-rare pork here. You want that really tender meat like for pulled pork. But you don't want it to be so tender that it actually pulls when you try to slice it. Aim for about 180°F internal temperature. That will be about 40 minutes per pound at 300°F.

Tip: Use an instant read thermometer to check it after 25 minutes per pound and then again every 5 minutes per pound after that. So if you have a 5 pound roast, you'll check it after 125 minutes (about 2 hours) and then every 25 minutes or so after that. It will probably take 3 and 1/2 hours to get to 180°F.

5) When the broth evaporates and has left a light brown layer on the bottom of the pan, add more (or add water). Be sure to add enough liquid so that it goes back up the sides of the pan. This is to dissolve any brownings on the sides of the pan from the previous round of broth. You want all of this brown flavor in your eventual gravy.

6) Put the roast back into the oven. When the liquid level gets low again, add more liquid again.

Let The Pork Roast Rest

7) When the roast gets to 180°F, take the roast out of the oven and let it rest for 30-40 minutes. It will be fine for up to an hour. There is no need to cover it during resting time. This is important because this is the only time the roast will rest. Don't skip this step.

You're probably wondering if the roast is going to get cold during this long rest. It actually stays warm inside for a long time though. Also, you're going to be putting the roast back into the oven for a bit and that will reheat it. Finally, it's my general opinion that once you carve a roast, those slices tend to cool down pretty quickly no matter what you've done. The key is to have a lot of really hot gravy to pour over it all. That makes it all warm and delicious!

It's Time For The REVERSE SEAR!

8) Preheat the oven to 475°F.

9) Put the roast onto a clean baking sheet, or rinse out the roasting pan it was previously in and use that. Put it into the hot oven for 13-17 minutes, uncovered. You want the outside to get really nice and brown and the fat to get crunchy.

10) Carve immediately and serve. Don't rest it when you take it out. It already rested earlier. Just get carving and eating!

Isn't that the coolest way to roast pork? It's low and slow so that it's tender, just the way you want it. And the outside is all brown and crunchy and full of flavor. I'm never going to roast pork another way.

Have a great day!

Christine :-)

DESCRIPTION

This is a method for how to roast pork butt and pork shoulder so that it is juicy and tender on the inside and has a gorgeous brown crust on the outside. It works perfectly every time! If you have a pork loin instead, get instructions for cooking it over here.

Listen to me explain briefly about how to make this amazingly perfect Roast Pork Recipe, with some great tips along the way, by clicking the play button below:

a boneless or bone in pork butt or pork shoulder (4-8 pounds is ideal)
1 and 1/2 tsp. black pepper
1 and 1/2 tsp. garlic powder
1 tsp. salt
low or no-sodium chicken broth

Take your pork roast out of the fridge and let it sit at room temperature for 30 minutes to an hour. Preheat oven to 300°F.
If your pork roast has a thick layer of fat on the outside, cut about half of it away so that it's a thinner layer. You can throw this out. Or, the best thing to do, is to turn it into a snack to have while your pork is roasting. Put the fat that you removed from the roast in a single layer on its own cake pan. Use a pan with edges because a lot of hot fatty liquid is going to come out of it. Season it lightly with salt. Roast the layer of fat in the 300F oven until it's brown and very crispy. Check it often. Blot it on kitchen towel. Break it into pieces and offer it as nibbles to anyone who is lured into your kitchen by the roasting pork smells.
Meanwhile, mix the pepper, garlic powder, and salt in a small bowl and then sprinkle liberally all over the roast.
Put the roast in a large roasting pan, fat-side-up. You do not need to use a rack in the pan.
Add about half an inch of low or no-sodium chicken broth to the bottom of the pan. Put it into the oven, uncovered.
Cook for 40 minutes per pound or until an instant read thermometer reaches 180F. This may seem high for pork but your goal is really tender, slow-cooked pork, almost like the texture of pulled pork.
If at any point most of the broth has evaporated, add more. Add enough to cover any brownings on the side of the pan from where the previous broth evaporated away. This will dissolve those brownings and flavor your gravy.
Take the roast out of the oven. Transfer it to a plate so that you can get at the roasting pan and make your gravy. Let the roast rest for 30-40 minutes. This is important because this is the only time the roast will rest. The roast does not need to be covered during resting time. Use this time to make your gravy. (Here's how to make gravy using the flavorful broth from the bottom of the roasting pan) and to finish off your other side dishes and set the table.
Preheat the oven to 475F.
Once the roast has rested, and the oven has preheated, and once you have everything else for your dinner just about ready, put the roast into a clean roasting pan or onto a baking sheet, uncovered, and put it into the hot oven for 13-17 minutes. You want the outside to get nice and brown.
When it's really nice and browned, take the roast out of the oven and immediately carve it* and serve it. Do not let it rest now since it has already rested.

Frequently Asked Questions

I answer a lot of questions in the comment section at the bottom so do read those, but here's a summary of the most frequently asked questions.

Can I roast 2 (or more) roasts side by side and how does this affect the cooking time?

As long as the roasts are not touching and there is room for air to circulate between them, the roasting time does not need to be adjusted. Weigh each roast on its own and determine how long it will take. The cooking times for each roast will be independent of the other roast there.

How do I make gravy for this roast?

Here is my tutorial for making gravy. This recipe uses the liquid from the roasting pan. If you want to make the gravy ahead of time, you totally can. Use this recipe for making gravy without drippings. Then, if you want to, you can add some of the liquid from the roasting pan while the roast is resting.

Can I brine the pork roast before cooking it?

Yes, you can use a brine or a marinade. I honestly don't think it's needed for the tender juicy cuts used here though(the butt and shoulder). It's more beneficial when doing a leaner cut like a loin or tenderloin. If you do brine the roast, you won't be able to use the liquids that drip out of it during roasting. They'll be too salty. You'll need to use the Gravy without Drippings recipe.

Can I put potatoes or other root vegetables in the roasting pan with my roast pork?

Yes. But then skip adding the liquid to the pan. You want the vegetables to roast, not boil. Arrange potatoes or other root vegetables around the roast in a single layer for the last hour of cooking. While the roast rests, you can put the veggies in a low oven to keep them warm, or you can let them keep roasting at a higher temperature to get a crust on them. Note that you won't get any drippings for gravy since the vegetables will soak up all the fat and juices from the roast. That's not a bad thing at all. Just go ahead and do the Gravy without Drippings mentioned above.

Can I make the roast ahead of time?

YES! My parents' restaurants used to do a lot of catering when I was a teenager, and so I did a lot of catering alongside them. What we used to do for turkeys is exactly what you should do for this roast pork if you have a crowd coming over. A day ahead, roast the pork. Follow the instructions above and roast it slowly at 300°F, then let it rest, then do the reverse sear, but then let it rest again. Let it rest until it's cooled down quite a bit. Then refrigerate it whole until chilled. This makes it really easy to get nice even slices because slicing it cold there are less juices flowing and everything holds together better.

Use an inexpensive electric knife, if you have one, to get nice thin slices. A carving knife works too just not as well and it gets tiring if you're doing a lot of slicing.

Arrange the slices in a single slightly overlapping layer on a large sheet pan. 40 minutes before you're serving dinner, dribble water or chicken stock over the pork slices. You want about 1 drop of water for every 3-4 slices. Very little water, really. But the water is going to heat and steam and keep the roast juicy. Next, cover the sheet pan with foil and then put it into the oven at 300°F until just heated through, about 25-30 minutes. Serve.

If you want to keep several trays of meat warm while serving, you can do that. Heat the trays all together in the oven at 300°F for 30 minutes. Then drop the heat down to 200°F so that you're just keeping them warm and not at risk of them actually cooking or starting to dry out.

How to store roast pork

I like to carve the entire roast and store it in the fridge in slices. The slices are easier to grab to use than having to haul out the whole roast and cut it every time. Put the slices in a sealed container. They'll keep for 3-4 days in the fridge. Or you can put them in a freezer bag and freeze them for a month.

What do I do with the leftovers from the roast pork?

Once you have the leftovers, you can do all kinds of things with them. You can use them anywhere you'd use cooked chicken. Put them on a salad or in a sandwich or wrap. They're great on a bun with BBQ sauce, like pulled pork sort of. You can mix them with any pasta sauce and serve with pasta. It's great chopped up and put with rice, like Chinese fried rice, or even white rice with peas and pork. The possibilities are endless!

Video by Leigh Olson. Article, photos and recipe by Christine Pittman.

Disclosure: This post contains Amazon affiliate links. If you click on one and buy something, I receive a small commission at no additional cost to you. All opinions are my own.

This post originally appeared in December 2014 and was revised and republished in December 2020.

How to Roast Pork Perfectly