Prime Rib vs Ribeye: The Difference Explained

By Dylan Clay
Last Updated 
April 20, 2022

If you ask anyone what their favorite cut of steak is, they're likely going say Ribeye.

However not many people realize that Prime Rib and Ribeye both come from the same place on the animal.

While they come from the same beef primal, they look, taste, and are cooked very differently.

The Differences Between Prime Rib and Ribeye

The main difference between prime rib and ribeye is in their method of cooking. A Ribeye steak is cooked over high heat and a prime rib is slow cooked.

Prime rib and ribeye also differ in terms of their size, taste, and general economics.

A ribeye steak is typically 1 - 2 inches thick and usually weighs 8 to 16 oz. A whole bone-in prime rib is the width of seven ribeyes and weighs anywhere from 14 to 22 lbs.

rib roast
This three bone rib roast is 10.75 lbs

In terms of taste, you won't find significant differences as they're from the same area of the steer. Again, the main difference in flavor stems from how they're cooked/prepared.

Ribeye steak is typically salt and peppered and then reverse seared over high heat. With prime-rib you'll often see herbs and spices used to develop an extraordinary crust (my Mom likes to inject garlic cloves) and then the meat is slow roasted under low heat.

In terms of economics, a prime rib is going to cost you more money than buying a single ribeye steak.

For example, we can look at two places I frequent for beef online:

Meat Provider Ribeye Roast Cost Ribeye Steak Cost
Wild Fork Foods $147.27 (6.7 lbs - USDA Prime) $17.49 (0.7 lbs - USDA Choice)
Snake River Farms $255 (5 lbs - Waygu Black Grade) $75 (0.94 lbs - Waygu Black Grade)
*Prices as of 3/14/2022

The Anatomy of the Rib Muscle

There are three major muscles that make up a ribeye steak. They are as follows:

  • Longissimus Dorsi - Eye of Ribeye
  • Spinalis Dorsi - Ribeye Cap
  • Complexus

These muscles are held together by a tender sinew membrane and large swaths of fat.

To break down these muscles, I've highlighted them in blue below:

Longissimus Dorsi

longissimus dorsi muscle

The Longissimus Dorsi or the eye of ribeye is the meatiest portion. All ribeyes have an eye - it is the center (or eye) of the cut.

The rib primal isn't a heavily exercised muscle and will collect a lot of intramuscular fat. Most of this marbling happens in the longissimus dorsi.

The eye is surrounded by two kernals of fat called the spinalis dorsi and the complexus.

Spinalis Dorsi

spinalis dorsi muscle

The Spinalis Dorsi is the cap of the ribeye. Of the three muscles, the Spinalis has superior intramuscular fat.

Without knowing it, most folks would likely find this part of the steak to be the most tender and flavorful part of the entire steak.

Complexus

complexus muscle

The Complexus is the smallest muscle of the ribeye. Depending on which rib (between 6 and 12) you receive, it may not even be present. For instance, a cut close to the front will receive a small piece of the complexus - literally a bite or two.

The spinalis and complexus are very similar, however you get significantly less of it.

What is Prime Rib

what is prime rib

A steer has 13 ribs per side. When a Butcher refers to these ribs, they start at the front of the animal and work their way back.

The first five ribs (1 - 5) are found in the beef chuck, the next 7 (6 - 12) are in the rib primal, and the 13th rib is part of the loin. This is also why there are so many different types of beef ribs.

prime rib location

A proper prime rib comes from the best part of a steer's rib - this is generally found in the middle - between rib bones 6 - 12.

Prime rib can also be referred to as a rib roast or standing rib roast - as the bones are standing as the meat roasts.

standing rib roast

A whole prime rib or a seven-rib roast can weigh anywhere from 14 to 22 lbs; Not only is this a lot of meat, it is also very expensive.

As a result, Butcher's will divide the roast into two smaller roasts - called a first and second cut.

  • First cut prime rib: Closer to the loin; Consists of ribs 10 - 12; Contains a large "eye."
  • Second cut prime rib: Closer to the beef chuck; Consists of ribs 6 - 9; Less uniform, contains more connective tissues, but more fat (flavor).

This area of the rib is prime because it has a thick fat cap and heavily marbled meat. This is the reason prime is used - not because the meat is USDA Prime Grade.

If we look at the United States Department of Agriculture (USDA) Food Standards and Labeling Policy handbook, we're told:

PRIME RIB OF BEEF OR STANDING BEEF RIB ROAST FOR PRIME RIB:
These products do not have to be derived from USDA prime grade beef.

USDA, Food Standards and Labeling Policy handbook, pg. 146.

How is Prime Rib Cooked

how is prime rib cooked

There are essentially two schools of thought when it comes to cooking prime rib:

  1. Sear first and then roast low and slow (180 - 225F) until medium-rare.
  2. Roast slowly first and then sear at medium-rare.

Either method works. The goal with both is to develop a great outer crust and a red center.

The way my Mother does is it (Her roast is pictured above) and how I was taught is to sear first and then roast in the oven until Medium-rare.

What is Rib-eye Steak

bone-in ribeye

A ribeye is a beef steak that comes from the rib primal or the cylindrical muscle that is close to the steer's rib.

A true rib eye steak is just the center longismissus dorsi muscle with the other two muscles and fat removed.

However, ribeye is sort of a catch-all term that's used to refer to this type of beef steak.

There are a few different ways to cut a ribeye steak. However, as a generalization ribeye steak is either bone-in or boneless.

When the bone is left in, it's commonly called a cowboy steak. When the bone is left to be long and is frenched, it's called a Tomahawk steak.

How is Ribeye Steak Cooked

Like most other cuts of steak, ribeye steak is cooked over high heat.

The conventional way to cook a steak is to sear over high heat and then to put the steak in the cool zone to come up to a desired internal temperature.

My preference for cooking steak is to do the above in reverse; What's referred to as a reverse sear.

two zone fire
Reverse Searing - Start in Cool Zone

In this case, the steak is placed in the cool zone and allowed to come up to near the finish temperature.

Temperature probing steak

For example, if your goal is medium rare, you might come up to a measured internal temperature like 125-130F, then sear in the hot zone. The steak should finish at around 130 - 135F or medium rare.

Searing Cowboy Steaks

This is also the reason resting steak can be problematic. If you opt to rest too long, you risk carry-over cooking (the surface temperature will carry over to the internal temperature) and serving a steak that goes from Medium-rare to medium pretty quickly.

Dylan Clay
I've grilled and smoked meat for roughly half my life. While i'm not a professional Pitmaster, I've worked with nearly every cut of meat. Not everyone has a hands on guide to teach them BBQ. It's my hope that Barbecue FAQ can be that helping hand.

Leave a Reply

Your email address will not be published.

BarbequeFAQ.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for website owners to earn advertising fees by advertising and linking to amazon(.com, .co.uk, .ca etc) and any other website that may be affiliated with Amazon Service LLC Associates Program.
Copyright © BarbecueFAQ
linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram