Sous vide London broil is one of the most reliable ways to turn a lean, relatively tough piece of beef into an evenly cooked, tender meal. The key is identifying the actual cut, using enough cooking time for tenderization, and finishing it with a fast, high-heat sear. For top round, the cooking time matters just as much as the water-bath temperature.
Quick Answer
For top-round London broil, 131°F (55°C) for about 24 hours is a useful starting point for a tender, steak-like result. Anova also uses 132°F (55.6°C) for 12–24 hours. Finish with a very hot, brief sear, then slice thinly against the grain. Low-temperature food safety depends on both time and thickness.
At a Glance
| Time Required | About 12–24 hours for top round, plus a brief sear |
| Difficulty | Easy once the bath is set |
| Tools Needed | Immersion circulator, water container, sous-vide-safe bag, and skillet or grill |
What Is the Sous Vide Cooking Method?
Sous vide means cooking food in a sealed bag in a precisely controlled water bath. Instead of exposing the outside of the beef to much higher heat than the center, the water bath brings the meat toward one controlled temperature and holds it there.
That control is especially useful with lean beef. A conventional grill or broiler can overcook the outside while you wait for the center to reach the desired doneness. Sous vide greatly reduces that temperature difference, so the meat can remain evenly pink from edge to edge before searing.
Time has a second job with tougher beef: tenderization. Douglas Baldwin’s practical sous-vide guide explains that prolonged low-temperature cooking weakens connective tissue, and specifically recommends extended cooking for tougher cuts such as top round.
Why Sous Vide Works So Well for London Broil
London broil is usually prepared from a lean cut with noticeable muscle fibers, so tenderness can be a challenge. Sous vide lets you hold that beef at a steak-like serving temperature for much longer than you could on a grill without steadily pushing the center toward well-done.
This distinction explains why London broil recipes online can give very different times. A short cook may be enough to bring a steak to its target temperature, while a longer cook is intended to soften a naturally firmer cut such as top round.
Sous vide also helps with consistency. Once you choose the water temperature, the center cannot race far beyond that bath temperature. You still need to control the final sear, though, because leaving the beef in a hot skillet too long can create an overcooked band around the outside.
Choosing the Right Cut for London Broil
Check the package rather than relying on the words “London broil” alone. The term is used for a preparation style, but retailers also use it as a name for certain steaks. In the United States, top round is one of the most common cuts sold this way.
The Beef Checkoff’s Top Round Steak guide lists “London Broil” as an alternate name for top round steak. Top round comes from the round primal in the rear leg, where frequently used muscles produce relatively lean, less-tender beef.
Flank steak is another traditional choice. It has a strong, obvious grain and should also be cut thinly across those fibers after cooking. Whatever the label says, knowing the actual cut helps you choose a sensible cooking time.
London Broil Sous Vide Time and Temperature
For top round, think of temperature as the doneness control and time as the tenderness control. A practical medium-rare starting point is around 131–132°F, with an extended cook rather than the short schedule used for naturally tender steaks.
| Guidance | Best Use | Temperature and Time |
|---|---|---|
| Baldwin top-round guidance | Tough top round with a medium-rare, steak-like texture | 131°F (55°C), about 24 hours |
| Anova London Broil recipe | Top-round London broil | 132°F (55.6°C), 12–24 hours |
| General steak schedule | Heating a naturally tender steak rather than tenderizing top round | Often much shorter; do not assume this produces the same tenderness in round |
| USDA consumer guidance | Simple whole-beef safety endpoint | 145°F (62.8°C) plus at least a 3-minute rest |
Anova’s London Broil recipe uses a top round steak at 132°F for 12 hours, with the option to continue up to 24 hours. Baldwin recommends roughly 24 hours at 131°F for top round roast, with longer low-temperature cooking producing greater connective-tissue breakdown.
That means there is no single universal time for every package labeled London broil. A thinner flank steak and a thick top-round roast do not have identical heating or tenderizing needs. Thickness, actual cut, starting temperature, and desired texture all matter.
Warning: Sous-vide food safety depends on both time and temperature. USDA consumer guidance recommends 145°F (62.8°C) with a 3-minute rest for whole beef steaks and roasts. If you cook at lower sous-vide temperatures, follow a validated time-and-thickness pasteurization schedule rather than judging safety by color.
The USDA safe minimum temperature chart gives the straightforward 145°F plus 3-minute-rest recommendation for beef steaks and roasts. Sous-vide schedules can use lower bath temperatures for longer periods, but those schedules must account for how long the center takes to heat and how long it remains at the required temperature.
Seasoning and Marinating London Broil
London broil works with either a simple dry seasoning or a marinade. Salt, black pepper, garlic, rosemary, thyme, soy sauce, Worcestershire sauce, vinegar, and similar savory seasonings all suit beef, but a marinade should support the meat rather than hide it.
If you marinate, do it in the refrigerator. USDA FSIS says most meat and poultry recipes call for about 6–24 hours and warns that very long marinating can eventually make the surface texture mushy. Its marinating guidance also says used raw-meat marinade should not be saved unless it is boiled before reuse.
Vacuum sealing does not automatically force a marinade deep into the center. Beef Research describes conventional marination as a relatively slow process involving passive absorption or osmosis; commercial processors use methods such as injection when they need more uniform distribution deep inside a cut.
For a simple sous vide London broil, you can season the beef, seal it, and let the extended cooking time handle the tenderness. If you use a strongly acidic marinade, remember that acid changes the meat’s surface texture and can also affect validated pasteurization timing.
Pro Tip: Before sealing, identify which direction the muscle fibers run. After searing, you can immediately slice across that grain instead of trying to find it on a browned surface.
How to Set Up the Sous Vide Water Bath
Set up the water bath so the circulator has enough water to heat and move freely around the bag. The beef should remain fully submerged, with water able to circulate around it throughout the long cook.
Use a bag intended for sous-vide cooking or a suitable heavy-duty resealable bag. Remove excess air so the bag stays in close contact with the meat and does not float. If necessary, secure the top of the bag to the container or use a suitable weight that will not obstruct circulation.
For long cooking sessions, water evaporation can become significant. Keep the water level within your circulator manufacturer’s operating range throughout the cook.
How to Sous Vide London Broil Step by Step
The process is straightforward: prepare the beef, seal it, cook it long enough for the cut you have, dry it thoroughly, and sear quickly. For a typical top-round London broil, the extended water-bath stage does most of the tenderizing work.
- Identify the cut. Check whether the package specifies top round, flank steak, or another cut sold as London broil.
- Trim as needed. Remove obvious silverskin or thick, tough exterior connective tissue while leaving useful meat intact.
- Season or marinate. Apply salt, pepper, garlic, herbs, or your preferred marinade. Keep marinating beef refrigerated.
- Preheat the water bath. For a steak-like top-round result, 131–132°F is a well-supported starting range.
- Seal the beef. Put it in a sous-vide-safe bag and remove enough air for close contact between the bag and meat.
- Cook until heated and tenderized. For top round, about 24 hours at 131°F is a useful reference point; Anova’s London broil recipe uses 132°F for 12–24 hours.
- Remove and dry thoroughly. Take the beef from the bag and pat every surface dry with paper towels. A wet surface browns slowly.
- Sear very quickly. Use a very hot skillet or grill to brown the exterior without significantly heating the center again.
- Slice across the grain. Cut the London broil into thin slices perpendicular to the long muscle fibers.
How to Sear London Broil After Sous Vide
Searing adds the browned crust that a water bath cannot create. Because the inside is already cooked, the goal is surface browning, not additional cooking through the center.
Remove the meat from the bag and pat it very dry. Heat a cast-iron skillet or other heavy pan over high heat, then add a small amount of oil suitable for high-temperature cooking. Place the London broil in the pan only after the surface is hot.
Sear briefly on each main side until a browned crust develops. The exact time depends on your pan and heat output, so watch the surface rather than using a long fixed timer. Anova’s London broil instructions use about one minute per side after the sous-vide cook.
If you add butter, garlic, rosemary, or thyme for flavor, add them near the end so they are less likely to burn during the hottest part of the sear.
Why Slicing Against the Grain Matters
Slicing technique can make a large difference with top round or flank steak. Cut across the visible muscle fibers instead of running your knife in the same direction as them.
Cutting across the grain shortens those long fibers into smaller segments, so each bite requires less chewing. Thin slices also make a lean cut feel more tender than thick slabs cut in the wrong direction.
Look at the raw meat before seasoning if the grain is difficult to see. On flank steak it is usually obvious; on round it may require closer inspection. Keep that direction in mind while cooking.
Serving and Pairing Suggestions
Sous vide London broil is versatile because the beef can be served as the center of a meal or sliced for other dishes. Its lean texture works especially well with a sauce or side that adds moisture and contrast.
- Serve thin slices with roasted vegetables and mashed or roasted potatoes.
- Pair the beef with grilled asparagus or a crisp salad for a lighter plate.
- Spoon chimichurri or garlic-herb butter over the sliced meat.
- Use cold or reheated slices in sandwiches, wraps, grain bowls, or salads.
- Add thinly sliced leftovers to tacos or quesadillas with salsa and pickled onions.
Whatever you serve with it, slice only what you need when possible. Keeping the remaining piece intact can help reduce moisture loss during storage.
How to Store and Reheat Leftover London Broil
Cool and refrigerate leftovers promptly. USDA FSIS recommends keeping cooked leftovers refrigerated for 3–4 days and reheating leftovers to 165°F when they are served hot.
Store the beef in a covered, airtight container or securely wrapped package. The USDA’s leftover food-safety guidance also recommends refrigerating perishable food within two hours of cooking, or within one hour when the surrounding temperature is above 90°F.
For the best texture, reheat only the amount you plan to eat. Thin slices warm quickly in a skillet, while cold London broil can go directly into salads or sandwiches without another cooking step.
Key Takeaways
- “London broil” can describe the preparation or the retail name, so identify the actual beef cut whenever possible.
- Top round benefits from a much longer sous-vide cook than a naturally tender steak because time is needed for tenderization.
- A useful top-round reference is about 131°F for 24 hours; Anova’s London broil recipe uses 132°F for 12–24 hours.
- Dry the surface thoroughly before a fast, high-heat sear so you create a crust without overcooking the center.
- Thin slicing across the grain is essential for the most tender eating texture.
Sous Vide London Broil: The Bottom Line
Sous vide is particularly useful for London broil because it separates two jobs that are harder to control with direct heat: reaching the desired doneness and giving a tough cut enough time to tenderize. For top round, an extended low-temperature cook followed by a quick sear produces a much more predictable result than treating it like a naturally tender steak.
Start by identifying your cut, choose a validated time-and-temperature schedule, keep the bag submerged, and dry the meat before searing. Then slice thinly across the grain before serving.
Frequently Asked Questions
What is sous vide cooking?
Sous vide is a method of cooking food in a sealed bag in a precisely controlled water bath. The controlled temperature helps the food cook evenly from edge to center and makes it possible to hold tougher meat at a relatively low temperature for an extended time.
What cut of beef is London broil?
London broil is not limited to one cut, although top round is commonly sold under that name and flank steak is also associated with the traditional preparation. Check the package for the actual cut because its thickness and amount of connective tissue affect the ideal sous-vide time.
How long should you sous vide London broil?
For top round, about 24 hours at 131°F is a useful starting point for a tender, steak-like texture. Anova’s London broil recipe uses 132°F for 12–24 hours. Shorter or longer times may suit other cuts or texture preferences, so identify the cut before choosing the schedule.
Do you have to marinate London broil before sous vide?
No, marinating is optional. A marinade can add flavor and affect surface tenderness, but you can get excellent results with salt, pepper, garlic, and herbs alone. If you do marinate raw beef, keep it refrigerated and handle or discard the used marinade safely.
Why do you sear London broil after sous vide?
Searing creates the browned crust and roasted flavors that a low-temperature water bath cannot provide. Pat the cooked beef dry first, then use very high heat for a short time so the surface browns without significantly overcooking the already-finished center.
Sources
- Douglas Baldwin, A Practical Guide to Sous Vide Cooking: sous-vide tenderization, pasteurization by thickness, and top-round time and temperature guidance.
- Anova Culinary, Sous Vide London Broil: top-round London broil temperature, 12–24-hour cooking range, searing, and slicing guidance.
- Beef. It’s What’s For Dinner, Top Round Steak: top round identification, alternate London Broil name, and characteristics of the cut.
- USDA Food Safety and Inspection Service: safe minimum internal temperature and rest-time guidance for whole beef steaks and roasts.
- USDA FSIS, Marinating Meat and Poultry: refrigerator marinating and marinade-handling guidance.
- USDA FSIS, Leftovers and Food Safety: refrigerator storage, prompt chilling, and reheating guidance.
