Pork Butt Fat Side Up or Down?

Have you ever considered whether you should smoke pork butts fat side up or down? I know personally, I’ve always put mine on the smoker fat cap up without giving it a second thought. However, there’s a lot of discourse on whether you should put your pork butt fat side up or down on the smoker. 

So what’s the correct answer? Should I have the fat cap up or down? And what the heck is a fat cap? As always when it comes to the finer points of barbecue, there’s some nuance to the answer. It can depend on the type of smoker, but if that’s not a problem, we here at Angry BBQ do cook our pork butts with the fat cap up. 

We will dive into the arguments for the fat side up or down when smoking, some of the negatives of both choices, and then defend our stance on why we prefer what we do. We’ll also talk about the physical makeup of a pork butt and how it affects the smoking process. Let’s tear into this like a smoked and rested pork butt!

What Is A Fat Cap And Why Does It Matter?

For starters, the fat cap is a thick layer of hard white fat that sits on the exterior of a pork butt or pork shoulder. For the full reasons why we use pork butts when we make pulled pork, check out our breakdown of pork butts vs pork shoulders. For a quick reason, the pork butt (or Boston butt) has more marbling (which is renderable fat) and is not as tough as a pork shoulder, making it ideal for turning into tender, juicy pulled pork.

So why do we care about the fat cap? Well, there’s a thick fatty layer only on one side of the pork butt. Therefore we should consider whether we should smoke pork butt fat side up or down. It’s also a thick layer of fat that isn’t something all that edible. So we need to figure out what we’re doing with it. 

If you’re smoking your pork butt fat side up, you should trim the fat cap down to around ¼ of an inch thickness, much like trimming a brisket. If you leave an extremely thick layer on, it won’t render properly. You don’t need to do much trimming if you’re smoking the fat side down.

Let’s take a look at the arguments for smoking pork butt fat side up or down.

Smoking Pork Fat Side Up

As I said earlier, this is what I default to every time I’ve smoked pork butts. However, just because I default to something doesn’t necessarily mean that it’s right. So why would you keep the fat up? 

One argument is that the fat will render down and help baste the meat. We know that all that fat will not be absorbed into the meat. Thankfully pork butts have plenty of intramuscular fat that will render down throughout the cooking process, keeping the interior of the meat nice and moist. However, the fat cap rendering can help keep the surface of the meat basted and protect against drying out.

Also, smoking your pork butt with the fat cap up can help when you’re using a smoker where the majority of the actual heat comes from above due to convection. It’s perfect for pellet grills and offset smokers.

Another good reason to smoke your pork butt with the fat up is so you can see the progress of the cooking process. Michael Haas models his pork butt recipe on legendary pitmaster Aaron Franklin’s method, and one of the indicators both men use for knowing when to wrap is the fat cap splitting apart as it renders. Now I typically follow the common procedure of cross-hatching the fat cap, but trimming and then observing the fat cap for splitting to judge on wrapping makes a lot of sense.

Downside To Smoking Fat Side Up

There are two major downsides to smoking with the fat up. The first one is if your smoker  generates a lot of heat directly under the cooking surface. The second major downside is the potential that as the fat melts, it could actually wash some of the dry seasoning rub off. However, as long as you season the pork butt liberally and don’t wrap it too soon, you should be okay.

Smoking Pork Butt Fat Side Down

However, we know that there’s an argument over whether we cook pork butt fat side up or down. So why would we keep the fat cap down? 

The biggest reason is if you’re smoking on a barrel, vertical, or similar style of smoker. Essentially, you want to smoke your pork butt fat cap down on any smoker or grill where the heat source is close to the bottom of the cooking area without much in the way of protection. The fat cap then serves as an insulator, protecting the meat from burning or overcooking. While pellet grills have a firebox that typically sits directly below the middle of the cooking chamber, the heat baffle or grease tray acts as a diverter plate causing the heat and smoke to rise along the sides, meaning you don’t have to worry about overheating from below.

Downside To Cooking Fat Side Down

There are two issues with smoking your pork butt fat cap down. One, the fat rendering and all the drippings falling straight down can cause flare-ups on an exposed direct heat source. The second issue is that the fat cap can stick to the grates making a big mess and potentially causing your pork butt to tear when you go to remove it. 

Is It Better To Smoke Pork Butt Fat Side Up Or Down?

If you smoke on any version of a barrel smoker or a vertical smoker like a Weber Smokey Mountain, you want to cook your pork butts fat side down. Otherwise, you want to keep your pork butt fat side up. It helps limit the fat sticking to the grill and also helps you judge visually if your pork butt is ready to be wrapped. 

Should I Flip My Pork Butt Midway Through Cooking?

You might have heard and read about people advocating for flipping your pork butt  throughout your smoking session. However, we want to open our smoker as little as possible, really only to spritz and wrap. Every time you open the lid of your grill or smoker, you’re losing heat and smoke which extends your cooking time. 

If you need to keep the fat cap down to protect the meat, you’re exposing the meat to extra heat that can burn it. You’re also potentially causing the fat cap to tear or at the very least make a big mess of the grates. We want to let the pork butt cook slowly and largely undisturbed to pick up all the flavors in the cooker, not be constantly jostled around.

Wrapping It Up

When it comes to smoking pork butt fat side up or down, we typically side with cooking with the fat cap up. However, if you have a barrel smoker or a bullet smoker like a Weber Smokey Mountain, you’ll want to keep the fat cap down to help protect the pork butt from the heat that sits underneath the cooking chamber. 

Michael reinforces that the splitting of the fat cap is an indicator of the pork butt being ready to wrap per Aaron Franklin. I always use a wireless meat thermometer like the ThermoWorks Twin TempSpikes (especially helpful if you’re smoking two pork butts!) for keeping an eye on a pork butt’s internal temperature both for the stall and to check on the tenderness to take it off the smoker. However, knowing when to wrap is a combination of the stall and the condition of the bark, and seeing the fat cap split is helpful in that regard.

Which way do you smoke a pork butt, fat cap up or down? What kind of smoker do you use? Let us know in the comments!

FAQS:

Question: How Much Pulled Pork Do I Need To Cook Per Person?

Answer: When you head to the store, you want to make sure you’re buying plenty of pork butt for everyone you’re planning on feeding. The last thing you want to happen is not having enough of that tender pulled pork to give everyone at least one serving, right? Here’s the rule of thumb: you want ⅓ of a pound of pulled pork per adult and ¼ of a pound per child you’re serving. 

There are two important factors to consider here, though. These numbers are for making pulled pork sandwiches. If you’re simply making a plate of pulled pork for everyone and it’s the only entrée, bump the number up to ½ of a pound for adults and a ⅓ of a pound for children. Secondly, these numbers are for cooked pulled pork. You’re going to lose roughly around 50% of a pork butt’s weight during the cooking process. 

So to figure out how much pork butt you need in pounds, you want to multiply the number of people you’re serving by ⅓, then double that number. Remember, you always want to have more than you need! Leftovers are good. For more details (and a handy-dandy calculator so you don’t have to do the math yourself,) check out our article on how much pulled pork per person you should cook.

Question: What Are Some Other Uses For Leftover Pulled Pork?

Answer: There are plenty of options if you want to enjoy your pulled pork other than on a plate or as a sandwich, though those are classics. One of my favorites is a pulled pork pizza! You can use your favorite pizza dough or even naan bread (I recommend garlic.) Drizzle with your favorite BBQ sauce, then layer with leftover pulled pork, cheddar cheese, mozzarella cheese, and red onions then cook until the dough is done and the cheese is melted. 

If you want to experiment with a breakfast dish using pulled pork, you can try pulled pork waffles. For that recipe plus many more, check out our favorite leftover pulled pork recipes including our very own Jannah Haas’ pulled pork shepherd’s pie!