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.
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.
Having the right equipment makes grilling London broil much easier and more successful. Here’s what you’ll need:
These essential tools will help ensure your London broil comes out perfect every time.
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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!
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.
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!
Stop guessing when your London broil is done! The ThermoPro TP20 wireless thermometer lets you monitor your meat’s temperature without opening the grill.
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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).
The type of grill you use will affect your cooking method slightly. Here’s how to adapt:
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.
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.
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.
The Weber Spirit II E-310 gas grill provides the consistent heat control needed for perfect London broil every time.
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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.
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!
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 |
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.
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.
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.
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.
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.
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.
Get everything you need for perfect London broil: thermometer, tongs, and carving knife in one convenient package.
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