Quick Answer
There are a few potential reasons why your grilled flank steak turned out tough:
- The meat was overcooked – Flank steak should be grilled to medium rare doneness to keep it tender. Cooking it past medium will make it tougher.
- The cut of meat was too lean – Flank steak is a very lean cut, so it can easily become tough and chewy if overcooked. Choosing a more marbled cut like ribeye can help avoid this.
- It wasn’t tenderized properly – Mechanical tenderization using a mallet or fork, or marinating with an acidic ingredient like wine or pineapple juice, can help break down the tough fibers in flank steak.
- It wasn’t sliced properly – Always slice flank steak across the grain after cooking. This shortens the muscle fibers and makes each bite more tender.
Examining Why Flank Steak Can Turn Out Tough
Flank steak comes from the abdominal muscles of the cow, so it gets a lot of exercise and is naturally very lean and fibrous. This makes the cut prone to becoming tough and chewy if not prepared just right. Here are some of the main reasons flank steak can turn out tough:
Overcooking
The #1 culprit behind tough flank steak is overcooking. Flank steak should be grilled quickly over high heat to the perfect doneness – medium rare. This means grilling to an internal temperature of about 135°F. Anything above medium (145°F) is going to make this cut get progressively tougher and drier. The high amount of exercise this area of the cow gets means the meat is densely packed with tough muscle fibers and connective tissue. Higher heat melts the connective tissue and keeps the muscle fibers tender. Too much heat causes both to seize up and stiffen.
Lack of Marbling
Flank steak is an extremely lean cut with little to no marbling (fat interspersed within the muscle). This fat helps keep the meat tender and moist during cooking. Cuts like ribeye or tenderloin have more extensive marbling, so they can better withstand higher cooking temperatures without drying out. The lack of fat in flank steak means it has less buffer against overcooking. Choosing a more marbled cut can help avoid turned out tough steaks.
Cut Against the Grain
Flank steak has a very pronounced grain – bundles of muscle fibers all running in the same direction. Slicing against the grain (perpendicular to the direction of the fibers) shortens these bundles, making the meat easier to chew and perceive as more tender. If flank steak is sliced parallel with the grain, those fibers remain long and stringy. Cutting properly matters! Always slice flank steak thinly across the grain after grilling.
Inadequate Tenderization
To break down the tough muscle fibers in flank steak, proper tenderization is key. Mechanical tenderization techniques like pounding with a meat mallet, scoring with a fork, or piercing with a Jaccard tenderizer can help. Marinating with ingredients like wine, vinegar, pineapple juice or yogurt that have acidic properties also gently break down tough tissues. Insufficient tenderization leaves the flank steak dense and chewy.
How to Keep Flank Steak Tender on the Grill
Follow these tips to ensure your grilled flank steak turns out perfect every time:
Choose the Right Thickness
Flank steak should be between 1/2 – 1 inch thick. This allows it to cook quickly over high heat without overcooking the center. Thinner cuts will dry out and thicker cuts won’t have time to cook through properly. Buy a flank steak in the 12-24 oz range and pound to an even thickness.
Tenderize Properly
Use a meat mallet, fork or tenderizer on both sides of the flank steak to break down those tough muscle fibers. Then marinate for 1-2 hours in an acidic ingredient like wine, citrus juice, vinegar or yogurt. The acid will further help tenderize the meat.
Preheat Properly
Get your grill very hot, about 450-500°F, and oil the grates right before placing the steak on. The high heat will sear the exterior and cook the interior before it has time to toughen. Shoot for 4-5 minutes per side over direct heat.
Check for Doneness
Use an instant read thermometer to check for medium rare doneness, 135°F. Resist the urge to cut into the steak to check – this will cause the juices to leak out. Let it rest 5 minutes before slicing.
Slice Against the Grain
Always slice flank steak thinly across the grain of the meat. This will make it much more tender and easier to chew.
Tips for Grilling the Perfect Flank Steak
Follow these flawless grilling methods for tender, juicy flank steak every time:
Choose the Right Steak
Pick a flank steak that is 1/2 – 1 pound and between 1/2 – 1 inch thick. Make sure it is bright red and that the grain is very visible running the length of the steak. Pass on steaks with thick seams of fat, which can flare up over high heat.
Trim Excess Fat
Since flank steak is so lean, only a minimal rim of fat needs to be trimmed. Using a sharp knife, trim off any thick chunks or flaps, leaving just a thin layer over the surface. Too much external fat can cause flare ups.
Tenderize Thoroughly
Use a meat mallet or fork to break up the dense muscle fibers on both sides. Then marinate for 1-2 hours in wine, citrus juice, vinegar, yogurt or other acidic ingredients. This one-two punch tenderizes flank steak perfectly.
Pat Steak Dry
Remove flank steak from the marinade and pat off any excess moisture with paper towels. The drier the surface, the better it will sear. Use paper towels to wipe off any excess oil or marinade too.
Season Generously
Coat both sides with a layer of salt and pepper. Flank steak loves big, bold spices and herbs. Garlic powder, onion powder, chili powder and cumin are all great options. Apply an even layer of dry rub.
Get the Grill Very Hot
Heat your grill to at least 450°F, preferably closer to 500°F if possible. Clean the grates and brush with oil right before adding the steak. The high heat is critical for getting that nice char.
Sear Both Sides
Place the flank steak over direct heat. Resist moving it for at least 3 minutes to get a good sear. Use tongs to flip and sear the other side for another 2-3 minutes. Shoot for rare to medium rare doneness.
Let It Rest
Transfer the steak to a cutting board and tent loosely with foil. Letting it rest 5-10 minutes allows the juices to redistribute evenly throughout the meat. Don’t skip this step!
Slice Against the Grain
Identify the direction of the muscle grain and slice the steak very thinly against the grain. This ensures maximum tenderness in each bite.
Common Mistakes to Avoid
Follow these flank steak grilling dos and don’ts:
Do:
- Pound it to tenderize
- Marinate in something acidic
- Pat it dry before grilling
- Use very high heat
- Let it rest before slicing
- Slice against the grain
Don’t:
- Buy a steak over 1 inch thick
- Trim off too much fat
- Overcrowd the grill
- Grill over low heat
- Press down on the steak with tongs or spatula
- Cut into the steak to check doneness
- Forget to slice against the grain
Follow these simple guidelines for grilling flank steak like a pro!
Frequently Asked Questions
What is flank steak?
Flank steak is a cut of beef that comes from the flank primal – the abdominal muscles of the cow. It is very lean and has a distinct longitudinal grain. It has robust beefy flavor but can be tricky to cook properly due to its leanness.
What is the best way to cook flank steak?
Grilling over very high direct heat is the ideal cooking method for flank steak. The high heat sears the outside while cooking the inside quickly before it can toughen. Grill to no more than medium rare doneness to keep it tender.
How long should I grill flank steak?
For a 1/2 – 1 inch thick flank steak, 4-5 minutes per side over high heat is ideal. Use a meat thermometer to check for 135°F for medium rare doneness. Let it rest 5 minutes before slicing.
What is the best marinade for flank steak?
Acidic marinades help tenderize flank steak. Red wine, beer, vinegar, citrus juices, yogurt and pineapple juice all work well. Add herbs, garlic, Worcestershire and soy sauce for flavor. Marinate 1-2 hours.
Should flank steak be grilled frozen?
No, grilling flank steak straight from frozen can negatively affect the texture. Always thaw in the refrigerator overnight before grilling. This allows any ice crystals to melt gently so they don’t damage the muscle fibers.
Conclusion
When grilling flank steak, focus on tenderizing it properly, cooking over high heat to the right doneness, letting it rest adequately, and slicing against the grain. Avoid overcooking this lean cut beyond medium and don’t forget to cut across those muscle fibers. With the right techniques, grilled flank steak can be tender, juicy and packed with big beefy flavor. Use this guide for your best steak night yet!