You grill a London broil by searing it over direct heat (450-500°F) for 4-6 minutes per side, then finishing it until the internal temperature reaches 130-135°F for medium-rare. The key to a perfect London broil is marinating it beforehand, using a reliable meat thermometer, and slicing it thinly against the grain after resting.
What Is London Broil?
Despite its name, London broil isn’t actually a cut of meat – it’s a cooking method. Most butchers label top round or flank steak as “London broil,” though you might also find it as sirloin tip or skirt steak. These cuts are lean, flavorful, and typically less expensive than premium steaks.
The traditional London broil method involves marinating a tough cut of beef, then cooking it quickly over high heat, and slicing it thinly against the grain. This technique transforms naturally tough cuts into tender, flavorful meals that won’t break your budget.
Essential Tools for Grilling London Broil
Having the right equipment makes grilling London broil much easier and more successful. Here’s what you’ll need:
Must-Have Grilling Tools
These essential tools will help ensure your London broil comes out perfect every time.
- Reliable Grill – Gas grills like the Weber Spirit II E-310 offer consistent temperature control, while charcoal grills provide more flavor but require more skill.
- Meat Thermometer – The ThermoPro TP20 wireless thermometer lets you monitor your meat’s temperature without opening the grill.
- Quality Tongs – OXO tongs with silicone tips give you a secure grip without piercing the meat and losing juices.
- Cutting Board – A sturdy carving board with a juice groove prevents messy countertops.
- Sharp Knife – A sharp carving knife makes slicing against the grain much easier.
- Marinade Container – A gallon-sized zip-top bag or glass container works perfectly.
- Timer – While not essential if you have a thermometer, a timer helps track flipping and resting times.
Grilling Safety Notes
Before firing up your grill, keep these important safety tips in mind:
Always position your grill at least 10 feet away from your home, deck railings, and overhanging branches. I once made the mistake of grilling too close to my vinyl siding – the repair was expensive!
- Grill Placement – Set up on a flat, stable surface away from high-traffic areas.
- Fire Management – Keep a spray bottle of water nearby for flare-ups, especially with fatty meats.
- Food Safety – Use separate plates and utensils for raw and cooked meat to prevent cross-contamination.
- Heat Protection – Always use heat-resistant gloves when adjusting hot grill grates.
- Proper Ventilation – Never grill in enclosed spaces due to carbon monoxide risk.
Best Marinades for London Broil
Marinating is crucial for London broil since it’s a naturally tough cut. A good marinade tenderizes the meat while adding flavor. For best results, marinate for at least 4 hours, but overnight (8-12 hours) is ideal.
Classic Balsamic Marinade (My Go-To Recipe)
- ¼ cup balsamic vinegar
- ¼ cup soy sauce (low sodium)
- ¼ cup olive oil
- 2 tablespoons Worcestershire sauce
- 3 cloves garlic, minced
- 1 tablespoon brown sugar
- 1 teaspoon dried Italian herbs
- ½ teaspoon black pepper
- ½ teaspoon red pepper flakes (optional)
Combine all ingredients in a zip-top bag, add your London broil, remove excess air, and refrigerate. Turn the bag occasionally to ensure even marinating.
I’ve found that adding an acidic component like balsamic vinegar or lemon juice is essential for breaking down tough muscle fibers. The first time I skipped this, my London broil was like chewing leather!
Marinade Variations
Herb Lover’s Marinade
- ¼ cup olive oil
- ¼ cup red wine vinegar
- 2 tablespoons fresh rosemary
- 2 tablespoons fresh thyme
- 4 cloves garlic, minced
- 1 tablespoon Dijon mustard
- 1 teaspoon salt
- ½ teaspoon pepper
Sweet & Spicy Marinade
- ¼ cup soy sauce
- 2 tablespoons honey
- 2 tablespoons lime juice
- 1 tablespoon sriracha
- 2 cloves garlic, minced
- 1 teaspoon ginger, grated
- 1 teaspoon sesame oil
How to Grill London Broil: Step-by-Step
- Prepare the meat – Remove London broil from the refrigerator 30-45 minutes before grilling to bring it to room temperature. This ensures more even cooking.
- Preheat your grill – Heat to high temperature (450-500°F). For gas grills, turn all burners to high. For charcoal, spread hot coals evenly.
- Remove from marinade – Take the meat out of the marinade and pat dry with paper towels. This helps achieve better searing.
- Season if needed – If your marinade was light on salt, add a light sprinkle of kosher salt and fresh black pepper.
- Oil the grates – Lightly oil your grill grates to prevent sticking. I use tongs holding an oil-soaked paper towel.
- Sear the meat – Place London broil on the hottest part of the grill at a 45-degree angle to the grates. Sear for 2-3 minutes.
- Create crosshatch marks – Rotate the meat 90 degrees (without flipping) and sear for another 2-3 minutes for those perfect grill marks.
- Flip and repeat – Turn the meat over and repeat the same process on the second side.
- Check temperature – Use your meat thermometer to monitor internal temperature. For medium-rare, aim for 130-135°F.
- Rest the meat – Remove from grill and let rest for 5-10 minutes on a cutting board. This allows juices to redistribute.
- Slice properly – Cut thin slices (¼ inch) against the grain at a slight angle for maximum tenderness.
Perfect Temperature Every Time
Stop guessing when your London broil is done! The ThermoPro TP20 wireless thermometer lets you monitor your meat’s temperature without opening the grill.
Temperature Guide for London Broil
Getting the temperature right is crucial for London broil. Since it’s a lean cut, cooking beyond medium will result in tough, dry meat.
| Doneness | Internal Temperature | Description | Recommended |
| Rare | 125°F (52°C) | Cool red center, very soft | Good option |
| Medium-Rare | 130-135°F (54-57°C) | Warm red center, tender | Best option |
| Medium | 140-145°F (60-63°C) | Pink center, slightly firm | Acceptable |
| Medium-Well | 150°F (66°C) | Slight pink, firm | Not recommended |
| Well Done | 160°F+ (71°C+) | No pink, tough | Avoid |
Pro Tip: Remove your London broil from the grill when it’s 5°F below your target temperature. The meat will continue cooking during the rest period (called carryover cooking).
Grilling London Broil on Different Types of Grills
The type of grill you use will affect your cooking method slightly. Here’s how to adapt:
Gas Grill
Pros: Easy temperature control, consistent heat
Method: Preheat all burners to high (450-500°F). Sear on high heat, then reduce to medium-high to finish cooking.
Recommended: Weber Spirit II E-310 provides excellent heat distribution.
Charcoal Grill
Pros: Superior flavor, higher heat potential
Method: Create a two-zone fire with coals on one side. Sear over direct heat, finish over indirect if needed.
Recommended: Weber Premium charcoal provides consistent heat.
Pellet Grill
Pros: Flavor infusion, temperature consistency
Method: Set to highest temperature (usually 450°F). May need slightly longer cooking time.
Recommended: Traeger pellets in hickory or mesquite enhance beef flavor.
Upgrade Your Grilling Game
The Weber Spirit II E-310 gas grill provides the consistent heat control needed for perfect London broil every time.
The Critical Importance of Proper Slicing
How you slice your London broil is just as important as how you cook it. Proper slicing can make the difference between tender, enjoyable meat and a tough, chewy disappointment.
- Identify the grain – Look for the lines running through the meat. This is the direction of the muscle fibers.
- Slice against the grain – Cut perpendicular to these lines, not parallel. This shortens the muscle fibers, making each bite more tender.
- Use a sharp knife – A dull knife will tear the meat rather than slice it cleanly.
- Slice thinly – Aim for ¼-inch thick slices or thinner.
- Cut at an angle – Hold your knife at a 45-degree angle to the cutting board for wider, more tender slices.
I ruined my first London broil by slicing with the grain instead of against it. The meat was perfectly cooked but nearly impossible to chew. Slicing technique matters more than you might think!
Troubleshooting Common London Broil Problems
Even experienced grillers encounter issues. Here’s how to solve the most common London broil problems:
| Problem | Possible Causes | Solution |
| Tough, chewy meat | Overcooked, insufficient marinating, sliced with the grain | Cook to medium-rare (130-135°F), marinate longer (8+ hours), slice against the grain |
| Too rare in center | Uneven thickness, insufficient cooking time | Pound meat to even thickness before marinating, use thermometer to verify doneness |
| Burnt exterior, raw interior | Grill too hot, meat too cold | Create two-zone fire, bring meat to room temperature before grilling |
| Flare-ups burning the meat | Excess marinade dripping, too much oil | Pat meat dry before grilling, keep spray bottle of water handy |
| Bland flavor | Insufficient marinating, not enough salt | Marinate longer, add more salt to marinade or season before grilling |
Frequently Asked Questions
How long should I marinate London broil?
For best results, marinate London broil for at least 4 hours, but preferably 8-12 hours (overnight). This gives the marinade enough time to tenderize the tough muscle fibers. Don’t marinate for more than 24 hours, as the meat can become mushy.
Can I grill a frozen London broil?
It’s not recommended. Grilling frozen London broil will result in uneven cooking—a burnt exterior and raw interior. Always thaw completely in the refrigerator (24-48 hours depending on thickness), then bring to room temperature before grilling.
What’s the best internal temperature for London broil?
For maximum tenderness and flavor, cook London broil to medium-rare (130-135°F). Since it’s a lean cut, cooking beyond medium (145°F) will result in tough, dry meat. Always use a meat thermometer for accuracy.
How do I know which way the grain runs in the meat?
Look for lines running through the raw meat—these are muscle fibers. In London broil, they typically run lengthwise. After cooking, identify the grain again (it may be less obvious) and slice perpendicular to these lines.
What sides pair well with London broil?
London broil pairs beautifully with grilled vegetables (asparagus, zucchini, bell peppers), baked potatoes, garlic bread, or a fresh salad. For a complete meal, I recommend a starch, a vegetable, and a sauce like chimichurri or horseradish cream.
Final Tips for London Broil Success
Grilling the perfect London broil comes down to a few key principles: proper marinating, accurate temperature control, and correct slicing technique. Remember that this cut shines when cooked to medium-rare and sliced thinly against the grain.
With the right tools and techniques, you can transform this affordable cut into a restaurant-quality meal that will impress family and friends. Don’t be discouraged if your first attempt isn’t perfect—each time you grill, you’ll gain experience and confidence.
Essential Grilling Kit
Get everything you need for perfect London broil: thermometer, tongs, and carving knife in one convenient package.
