Can You Really Make London Broil Tender?
Yes, but not through the smoker alone. London broil is a lean cut (often top round or flank) without much of the connective tissue that breaks down during a long, slow cook — so smoking it doesn’t tenderize it the same way smoking a brisket or pork shoulder does. What actually makes it tender is a combination of marinating beforehand, not cooking it past medium, and slicing thin against the grain afterward. Smoking adds flavor and a controlled, even cook; it’s the marinade and the knife work that do most of the tenderizing.
What You Need
- London broil (top round or flank), about 1-2 inches thick
- Marinade: oil, an acidic component (vinegar, citrus, or Worcestershire), garlic, and herbs
- A simple dry rub (optional, in addition to or instead of a marinade)
- Instant-read thermometer
How to Smoke London Broil Step by Step
Marinate for Tenderness
Marinate for at least 2 hours, ideally overnight. The acid in the marinade is doing real work here — it’s the main lever you have for tenderizing this cut before it ever touches heat.
Season with a Rub
Pat the meat dry and apply a simple rub if you’re using one — salt, pepper, garlic powder, and paprika work well without competing with the marinade flavor underneath.
Smoke at 225°F
Place the London broil on a preheated smoker at 225°F.
Pull at 135°F Internal
Cook to an internal temperature of 135°F, checking with a thermometer rather than guessing by time — London broil’s thickness varies enough that clock-based timing isn’t reliable.
Rest and Slice Against the Grain
Rest for 10 minutes, then slice thin, against the grain. This is the single most important step for perceived tenderness on this cut — even a well-cooked London broil will taste tough if sliced the wrong way.
How Long to Smoke London Broil at 225°F
For a 1-2 inch thick London broil at a steady 225°F, expect roughly 1.5 to 2.5 hours to reach 135°F internal, depending on exact thickness and how consistently your smoker holds temperature. Go by the thermometer, not the clock — actual time varies more than with a uniform cut because London broil trims aren’t perfectly consistent in shape.
Does Cooking London Broil Longer Make It More Tender?
No — and this is a common misconception carried over from cuts like brisket. Brisket and chuck are full of collagen that slowly converts to gelatin over hours of cooking, which is what makes long cook times tenderize them. London broil doesn’t have much of that connective tissue to begin with, so cooking it longer past your target internal temperature doesn’t add tenderness — it just dries the meat out further since it’s already lean. Pull it at 135°F for medium-rare and stop there; extra time in the smoker works against you on this cut.
In a Hurry? Grill It Instead
Smoking gives you a slower, more controlled cook, but if you want London broil on the table faster, our guide to grilling London broil covers direct-heat grilling, which gets a 1-inch cut done in about 10-12 minutes.
FAQ
How long does it take to smoke a London broil at 225? Roughly 1.5 to 2.5 hours for a 1-2 inch cut to reach 135°F internal, depending on thickness — confirm with a thermometer.
Is it possible to make London broil tender? Yes, mainly through marinating beforehand, not overcooking it, and slicing thin against the grain — the smoker itself doesn’t tenderize this lean cut the way it does a fattier, collagen-rich one.
Will London broil get more tender the longer it cooks? No. Unlike brisket, London broil doesn’t have much connective tissue to break down, so cooking past your target temperature just dries it out rather than tenderizing it further.
How do I cook a London broil in a smoker? Marinate it, season with a light rub, smoke at 225°F until it reaches 135°F internal, then rest and slice thin against the grain.