When it comes to beef, it doesn't get much more impressive—or expensive—than a porterhouse steak.
The porterhouse is a crosscut bone-in slice of the short loin. It features the buttery tenderloin on one side of the bone and a section of the beefy strip loin, which we also call a New York strip steak, on the other.
Now, to qualify as a porterhouse, the tenderloin section must be at least 1¼ inches in diameter. Anything smaller has to be labeled a T-bone.
When shopping for a porterhouse at the supermarket, you may be inclined to look for the steak with the largest tenderloin portion possible. More tenderloin is better, right?
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Well, not exactly. It turns out that where the tenderloin is largest, roughly the last six inches of the short loin before it meets up with the sirloin, the accompanying strip portion is divided by a line of tough sinew. On the outside of that line, sits a portion of top sirloin, a much more heavily used muscle. Steaks from this section are known as a vein-end porterhouse, and while they look impressive, butchers report that they aren't much fun to eat.
To see and taste the difference ourselves, we visited Kinnealey Quality Meats in Brockton, Massachusetts, where butchers cut us both vein-end and center-cut porterhouses from three different short loins.
Back in the kitchen, sure enough, once tasters crossed the vein of sinew, they were met with a significantly chewier piece of meat. The section of top sirloin was not only tougher, but it was streaked with chewy connective tissue and rubbery fat. So if you don't want to pay porterhouse prices for sirloin quality, look for a porterhouse where the strip is vein- and top sirloin-free.