How to Grill Flank Steak So It Stays Tender

The short answer

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Grill flank steak over very hot direct heat, check its center early with an instant-read thermometer, rest it, and slice it thinly across the visible muscle grain. Those last two words, across the grain, matter as much as the marinade or fire. Flank is lean and strongly grained. Long intact fibers feel chewy; short fibers are much easier to bite through.

USDA FSIS lists 145°F followed by at least a three-minute rest as the safe minimum for whole beef steaks on its safe temperature chart. That matches MeatLogic's meat temperature chart. Many steak recipes target 130°F to 135°F for medium-rare flank. That range is below the USDA consumer minimum and is a personal risk choice, not a USDA-safe recommendation. Use 145°F plus the rest when you want the straightforward safety path, especially for anyone at higher risk from foodborne illness.

A typical flank steak may cook in roughly 8 to 12 minutes over a properly heated grill, but thickness, fire strength, starting temperature, and wind change the result. Cook to internal temperature, not to the clock.

Why flank steak can be tender or tough

Flank comes from the abdominal area of the animal. It is a broad, relatively thin muscle with a bold beef flavor and long, obvious fibers. It does not have the heavy internal marbling of ribeye, so there is less fat protecting it from excessive heat. It also does not contain the kind of collagen that rewards a short steak cook and somehow turns soft along the way.

The cut becomes enjoyable through a different combination: high heat builds a browned crust quickly, controlled internal temperature preserves moisture, and thin cross-grain slicing shortens the fibers. Miss any one of those and dinner can feel tougher than it should.

ThermoWorks' 2025 flank steak guide makes the same central points about the cut's thin shape, easy-to-read grain, and need for temperature control. The Team at MeatLogic would add one habit before seasoning: study the raw steak and note which direction its grain runs. It is easier to see now than after a dark crust forms.

Flank steak versus skirt steak

The names are often swapped at meat counters, but flank and skirt are different cuts. Flank is generally broad, flat, and comparatively uniform, with straight grain running across its width. Skirt is narrower, looser textured, and usually more irregular. Both reward high heat and cross-grain slicing, but skirt often cooks even faster because it is thinner.

Do not assume every package labeled London broil contains flank. London broil describes a preparation more than a single cut, and stores may use top round. Read the package and look at the meat. A true flank steak normally resembles a large tapered rectangle with pronounced parallel fibers.

That distinction affects timing. A one-inch flank can remain on the grill longer than a half-inch skirt without reaching the same center temperature. Treat the thermometer reading as the truth and the printed cut name as useful context.

How much flank steak to buy

Plan about 6 to 8 ounces of raw flank steak per adult when it is the main protein with substantial sides. Increase the amount for very hungry guests or a meal built mostly around beef. Reduce it when the steak will be sliced into tacos, grain bowls, or a large salad with several other components.

Use the portion calculator for a larger group. One broad steak often weighs around 1 1/2 to 2 1/2 pounds, but packages vary. Two smaller steaks are easier to manage than one oversized piece when the grill has uneven heat.

Choose beef with a fresh red color, clean smell, and no dried edges. A little external fat is fine, but flank should not need aggressive trimming. Avoid a piece with one paper-thin end and a very thick opposite end unless you are willing to cut it into separate portions. Even thickness makes the finish easier to control.

Should you marinate flank steak?

A marinade is useful for flavor and surface seasoning, but it does not turn the entire steak into a different cut. Salt can move inward over time. Aromatic molecules mostly remain near the surface. Acid changes surface proteins, and too much acid for too long can make the outside soft or chalky while the interior remains recognizably flank steak.

For a balanced marinade, combine:

• 1/4 cup soy sauce
• 2 tablespoons neutral oil
• 2 tablespoons lime juice or red wine vinegar
• 1 tablespoon Worcestershire sauce
• 2 grated garlic cloves
• 1 teaspoon brown sugar or honey
• 1/2 teaspoon black pepper
• Optional chile flakes, cumin, or chopped herbs

This is enough for roughly 1 1/2 to 2 pounds of steak. Marinate in a covered nonreactive container or sealed bag in the refrigerator for 2 to 8 hours. Turn it once if the liquid does not fully surround the meat. A full day in a sharp acidic mixture can damage the surface texture.

If you prefer pure beef flavor, skip the liquid marinade. Salt the steak evenly and refrigerate it uncovered on a rack for several hours. That dry surface browns well. Our dry-brine steak guide explains the timing and why salt weight is more reliable than spoon volume.

Never reuse raw-meat marinade as a table sauce unless it has been boiled safely. An easier plan is to reserve a clean portion before the steak enters the mixture.

Equipment that makes the cook easier

You do not need specialized steak gear, but a few tools solve predictable problems:

• An instant-read meat thermometer for checking several spots
• Long grill tongs for flipping without piercing the meat
• A sharp slicing knife for thin cross-grain slices
• A clean cutting board large enough to hold the whole steak
• A clean platter that never held raw beef

Use separate tools or wash them thoroughly after they touch raw meat. USDA FSIS warns against putting cooked food back onto a platter or board that held raw beef. The same separation applies to tongs and marinade brushes.

Build a hot zone and a safe zone

On a charcoal grill, light enough fuel for a concentrated hot area and leave part of the grate without coals underneath. Our two-zone charcoal fire guide shows the layout. On a gas grill, preheat all burners, then leave one burner lower or off once the grates are hot.

The direct side should be hot enough to brown the steak quickly. The cooler side is insurance. It gives you somewhere to move the beef if a sugary marinade starts scorching before the center is ready. It also lets you hold one steak briefly while another finishes.

Clean the grate after it heats. Then oil the steak lightly rather than flooding the grill. Aerosol oil aimed at flame can flare. A folded paper towel held with long tongs can apply a very thin coat to the grate if needed.

Keep the lid nearby. Closing it can help heat reach the center of a thicker section, but flank is still primarily a direct, hot cook. Do not turn a lean thin steak into a long indirect roast unless its unusual thickness demands it.

Step-by-step grilling method

1. Remove excess marinade

Take the steak from the refrigerator while the grill preheats. Remove it from the marinade and let the excess drip away. Pat very wet patches gently with paper towels. A thin flavorful coating is useful; liquid pooling on the surface must steam away before browning can begin.

Do not leave raw beef on the counter for an hour to "bring it to room temperature." The center will remain cool while the surface warms. A strong fire and direct measurement handle the temperature difference more safely.

2. Mark the grain

Look for the parallel muscle lines. Cut a tiny notch across one corner or take a phone photo so you remember their direction after cooking. Your final knife cuts will run perpendicular to those lines.

3. Sear the first side

Lay the steak flat over direct heat. If one end is much thinner, angle that end toward a slightly cooler part of the grate. Leave the steak alone long enough to make solid contact and form a dark browned surface. Constant lifting slows browning and makes it harder to learn the fire.

4. Flip and begin checking

Flip with tongs after the first side has a strong sear, often around four to six minutes. Begin checking the center after a few minutes on the second side. Insert the probe from the side into the thickest area so more of the sensing tip stays inside the thin steak. Check at least two nearby spots because flank thickness changes across the cut.

5. Choose the finish knowingly

For the USDA-safe path, keep cooking until the coldest checked area reaches 145°F, then rest at least three minutes. If you choose a medium-rare result around 130°F to 135°F, understand that it is below the USDA minimum. Do not describe it to guests as the USDA-safe option, and choose the 145°F route for pregnant people, young children, older adults, or anyone with a weakened immune system.

6. Rest before slicing

Move the steak to a clean board and rest it at least three minutes for the USDA path. Five to ten minutes makes slicing cleaner on a large flank. Do not seal it tightly in foil, which can soften the browned surface and trap steam.

7. Slice across the grain

Rotate the steak so the muscle fibers run left to right in front of you. Cut downward across them, not parallel with them. Make thin slices, around 1/4 inch, and angle the knife slightly if you want broader pieces. A sharp blade matters because sawing crushes the cooked surface and squeezes out juices.

The video below demonstrates marinating, hot grilling, resting, and the final cross-grain cut. Its medium-rare target is a preference below the USDA safe minimum, so use the temperature path stated in this guide for your own risk needs.

A practical temperature guide

The site's general beef doneness ranges help describe texture, but only the USDA minimum is presented here as the simple safety endpoint.

Final center temperature	Typical appearance and texture	Safety context
130°F to 135°F	Rosy medium-rare, juicier, softer	Below USDA minimum; personal risk choice
135°F to 145°F	Medium to medium-well	Still below the USDA endpoint until 145°F is reached
145°F plus 3-minute rest	Less pink, firmer	USDA FSIS safe minimum for whole beef steaks
Above 155°F	Little pink, increasingly firm	Safe but flank can become dry and chewy

Carryover depends on thickness, fire intensity, and rest conditions. Thin flank has less stored heat than a large roast, so do not subtract a universal number and assume it will coast to safety. If your plan requires 145°F before removal, measure 145°F before removal as USDA guidance states.

How to slice flank steak correctly

Slicing is not presentation trivia. Imagine each muscle fiber as a long cord. Cut with the grain and each bite contains long cords that your teeth must shorten. Cut across the grain and the knife does that work first.

If the grain bends slightly across a large steak, divide the cooked flank into two or three sections, rotate each section, then slice it correctly. A single knife angle across the whole piece may be wrong near one end. The grain-marked Commons image above is useful because it shows how visible those lines can be before cooking.

Do not slice the entire steak far ahead of service. Thin pieces cool quickly and expose more surface to air. Rest the whole piece, slice what you need, and spoon any clean board juices over the meat.

Gas, charcoal, and pellet grill adjustments

Gas grill

Preheat longer than the hood dial suggests because the metal grate needs stored heat. Use the hottest burners for the first side and keep a lower burner available. Close the lid between checks if wind is stealing heat, but avoid repeated long lid openings.

Charcoal grill

Wait until the initial heavy ignition smoke clears. Spread a compact direct zone rather than a thin layer across the whole kettle. Flank benefits from concentrated radiant heat, and the empty side protects it from flare-ups. Our lump charcoal versus briquettes guide can help you choose a fuel behavior.

Pellet grill

A pellet grill can cook flank, but many models do not deliver the same direct radiant heat as a charcoal or gas sear zone. Use the manufacturer's approved high-heat setting or sear accessory. A preheated cast-iron surface can improve browning, provided it does not obstruct required airflow or grease drainage. Do not extend the cook just to chase smoke flavor. Flank reaches its center target quickly.

Marinade flavors that work

Keep the same salt, oil, and modest acid structure, then change the aromatics.

Garlic and rosemary

Use red wine vinegar, Worcestershire sauce, garlic, rosemary, black pepper, and a little brown sugar. This profile works well with potatoes and grilled vegetables.

Lime and cumin

Use lime juice, soy sauce, neutral oil, garlic, cumin, oregano, and chile. Slice the beef thinly for tacos. Keep toppings ready before the steak comes off so the slices are served warm.

Ginger and scallion

Use soy sauce, neutral oil, rice vinegar, ginger, scallion, garlic, and a small amount of sugar. Avoid adding all the sugar at the beginning if your fire is extremely hot, because a sweet surface burns quickly.

Salt content matters across all three. Soy sauce, Worcestershire sauce, bottled rubs, and prepared sauces can stack sodium. Taste the clean marinade before it touches raw meat and adjust deliberately.

Common flank steak mistakes

Cooking by minutes alone

Recipe timing assumes a thickness and fire you may not have. Begin checking early. The difference between juicy and dry can be a few minutes on a thin cut.

Leaving the surface dripping wet

Excess marinade cools the grate and delays browning. Drain it and remove obvious wetness before grilling.

Using a weak fire

Flank needs fast surface browning. A lukewarm grill cooks the center while the outside remains pale, tempting you to leave the steak on too long.

Burning a sweet marinade

Sugar darkens fast. Move the steak to the cooler zone if the exterior threatens to burn before the center reaches the temperature you chose.

Guessing doneness from color

Marinades, lighting, and smoke can change appearance. Measure the center. Color alone cannot confirm safety.

Slicing with the grain

This is the classic failure. Even perfectly cooked flank feels stringy when cut parallel to its fibers. Reorient the board and cut across them.

Serving ideas

Flank steak is built for dishes that use thin slices. Serve it in warm tortillas with onions and salsa, over rice with grilled scallions, or on a crisp salad with a sharp vinaigrette. For sandwiches, cut the slices shorter again so diners do not pull an entire strip from the bread in one bite.

Our chimichurri for grilled steak is a natural finishing sauce. Make it before lighting the grill and keep it separate from raw beef tools. A bright sauce helps a lean cut without burying its flavor.

For a buffet, keep cooked meat at 140°F or above or refrigerate it promptly. Do not let sliced steak linger at room temperature. Thin slices cool fast, so put out smaller platters and replenish them instead of exposing the whole batch at once.

Leftovers and reheating

USDA FSIS says to refrigerate cooked leftovers within two hours, or within one hour when the air temperature is above 90°F. Store the steak whole when possible, then slice after reheating. A whole piece loses moisture more slowly than a pile of thin strips.

USDA FSIS lists 165°F for reheated leftovers on its safe temperature chart. Warm the steak covered with a spoonful of broth or sauce, then verify the center. For cold salad or sandwiches, use properly chilled leftovers within a safe storage window and keep them cold until service.

The method in our steak reheating guide separates gentle warming from a brief surface refresh. Flank is thin, so shorten each stage and check early.

Final checklist

• Choose a broad, evenly thick flank steak.
• Note the grain direction before seasoning.
• Marinate 2 to 8 hours, or dry-brine instead.
• Drain and dry the surface before grilling.
• Build a very hot direct zone plus a cooler escape zone.
• Check more than one spot with an instant-read thermometer.
• Use 145°F plus a three-minute rest for the USDA-safe path.
• Treat medium-rare flank as a personal risk choice below the USDA minimum.
• Rest the steak, then slice it thinly across the grain.
• Move cooked beef to a clean board and utensils.

Flank steak is not difficult once you stop treating it like a thick ribeye. Give it a short, hot cook, make an informed temperature decision, and let the knife shorten the fibers. That combination produces the tender, beefy slices the cut is capable of delivering.