Etymology: There is some difference of opinion on the origin of the word “Porterhouse,” with several restaurants and cities claiming to have created the name. For example, Martin Morrison served large T-bones in his Pearl Street (Manhattan) “Porter House” around 1814. This history was popular in the late 1800’s, but some say a Cambridge, Massachusetts proprietor by the name of Zachariah B. Porter added his name to the steak. Still, others argue that the Porterhouse name stems from various 19th Century U.S. hotels or restaurants called Porter House, such as the Porter House Hotel in Flowery Branch, Georgia.

Anatomy: The Porterhouse is a cut of steak from the short loin portion of the animal that contains both strip loin and tenderloin meats. See the highlighted portion in the diagram below:

It is cut from a lumbar vertebra that is sawed in half through the vertebral column.

The downward prong of the “T” is a transverse process of the vertebra, and the flesh that surrounds it (spinal muscles) makes up the meat of the Porterhouse.

Essentially, it is a large T-bone steak from the rear of the animal that has two different types of meat (tenderloin and strip loin), one on either side of the “T.” In the picture below, the strip loin or Strip Steak is on the right, and the tenderloin or Filet Mignon is on the left.

The small semicircle at the top of the ‘T’ is half of the vertebral foramen, which is the name of the hole that passes through each vertebra for housing and protecting the spinal cord. They run the whole way up the back, all the way up to the brain of the animal.

The anatomy of a Porterhouse differs from that of a T-bone only in that the Porterhouse contains a larger portion of tenderloin than its T-bone counterpart.

This is primarily due to the fact that Porterhouse steaks are cut from further in the rear of the animal, from lumbar vertebrae, where the tenderloin is much thicker. Experts differ, however, on how large the tenderloin must be to differentiate a Porterhouse from a T-bone. The U.S. Department of Agriculture’s Institutional Meat Purchase Specifications state that the tenderloin of a Porterhouse must be at least 1.25 inches thick at its widest, while that of a T-bone must be at least 0.5 inches.

Here is a shot of a short loin with multiple vertebrae still intact and not portioned out into individual Porterhouses and T-bones.

You can see on the left there is a good sized, thick portion of tenderloin. That thins down as you move the the right, and seems to disappear by time your eyes reach the far end of the cut.

Just to drive home the anatomy a little more, here is a great excerpt and image from Russ Cooks:

“Up close and personal, this is where the T-bone fits.

The black line across the top of the two T-bones pictured here is the outside (top of the back) of the steer. You can see the T-bone in the schematic illustration higher up on this page as the topmost part labelled Rib. Above the ribs, what you touch if you pat the steer’s back, is the New York strip. Beneath the ribs is the tenderloin from which a filet mignon is often cut. T-bone steaks cut closer to the shoulder are known as Porterhouse while those cut closer to the loin are just T-bones.”

Preparation: Most times, T-bones and Porterhouses are either grilled, seared in a pan, broiled or blasted with high heat in specialty steak ovens made for charring the outside of the meat without over-cooking the inside. Butter is essential, and heavy seasoning is important as well. Herbs and garlic help boost the flavor too.

Flavor: Since this cut contains both the Filet Mignon and the Strip Steak, I refer you to the flavor sections for those cuts below, with a notation that the bone being left in often adds a more robust flavor while helping to retain tenderness and juiciness. These are very popular items at steakhouses because they can be cut large enough to feed anywhere from two to four people. Additionally, with two different types of meat in one steak, one can vary the flavors that one experiences with each bite.