Flank Steak Vs Skirt Steak: What's The Difference?

What is flank steak?

Flank steak is a long, flat cut from the abdominal muscles (belly) of the cow, below the loin and short ribs. The cut is about 1.5-2 inches thick and weighs 1.5-3 pounds typically, with prominent grain running lengthwise. Flank steak is relatively lean (about 9-10 grams of fat per 4 oz serving) and slightly tougher than premium steaks because of the active muscle group. The lean profile and prominent grain make flank steak ideal for marinating (which tenderizes) and high-heat cooking (which sears without overcooking). Common preparations: fajitas, stir-fries, beef and broccoli, London broil-style roasts, and steak salads. Slice flank steak against the grain after cooking to maximize tenderness; cutting with the grain leaves long meat fibers that feel chewy.

What is skirt steak?

Skirt steak comes from the diaphragm muscle of the cow, separating the chest cavity from the abdomen. There are two cuts: inside skirt (from inside the rib cage) and outside skirt (between the ribs and abdomen), with outside skirt being more tender and flavorful. Skirt steak is thinner than flank steak (about 1 inch thick) but longer, sometimes 20+ inches in length, with prominent loose grain. The diaphragm muscle gets steady use throughout the cow's life, giving skirt steak intense beef flavor and slightly more marbling than flank steak. Skirt steak is the original cut used in Tex-Mex fajitas (the word 'fajita' comes from 'faja,' Spanish for belt or sash, referencing the long shape).

How do flank and skirt steak compare in cooking?

Both cuts work best with high-heat cooking methods that quickly sear the exterior without overcooking the interior. Grilling, broiling, and pan-searing all work well; both should be cooked to medium-rare or medium (about 130-140 degrees F internal temperature) for best tenderness. Overcooking either cut produces tough, chewy results. Skirt steak cooks faster due to the thinner profile (4-5 minutes per side over high heat); flank steak takes 6-8 minutes per side. Both benefit from marinating in acidic, oil-based mixtures for 2-4 hours to tenderize the meat fibers. Always slice against the grain after a 5-10 minute rest. Skirt steak's looser grain is more forgiving for cutting; flank steak's tighter grain requires careful slicing.

Can you substitute one for the other?

Yes, flank and skirt steak substitute for each other in nearly all recipes with minor adjustments. Both work in fajitas, stir-fries, tacos, salads, and sandwiches. Skirt steak's higher fat content gives slightly more flavor; flank steak's leaner profile makes it slightly drier when overcooked. Adjust cooking time based on which you have: skirt steak (4-5 min/side) vs flank steak (6-8 min/side). When skirt steak isn't available (it's often more expensive or sells out faster), flank steak is the standard substitute. Hanger steak is another close substitute for both. For Korean barbecue (galbi or bulgogi style), thinly sliced flank or skirt both work; the marinade and slicing matter more than the specific cut.