beef Round
Top Round
The large lean muscle from the inside of the hind leg — the semimembranosus. Of the three round muscles it is the most tender, which is a low bar: no marbling, a coarse parallel grain, and a job that involves moving the animal forward every step of its life.
In one line
Cheap, lean, and the reason "London broil" is on so many labels.
Buy it if
You want a big roast for sandwiches or a thin-sliced dinner and you own a thermometer.
"London broil" is a method, not a cut. It means marinate a lean slab, sear it hard, slice it thin. Top round wears the label most often because it is the cheapest muscle big enough to do the job, but flank, bottom round and sirloin tip all get the same sticker — and the sticker tends to add a dollar or two a pound to a cut that has not earned it. Read the muscle name on the package, not the recipe name.
It has a cap. A thinner, looser-grained muscle lies over the main one and peels away along a natural seam. It eats more tenderly than what is underneath and cooks faster, so on a whole roast it is worth separating rather than fighting.
Why this muscle ends up sliced. Top round is close to a rectangular block of one uniform grain, which is exactly what a deli slicer wants — every slice the same size, no seams to steer around, no fat to trim. Most of the demand for it comes from processing rather than the steak counter, and that, more than tenderness, is what sets the price.
Where it comes from on the animal
| Species | beef |
|---|---|
| Primal | Round |
| Subprimal | top (inside) round — semimembranosus, plus the gracilis cap over it |
What else it’s called
How to cook Top Round
| Best methods | Roast Sous vide Grill Smoke Pan sear Braise |
|---|---|
| Cook to | Pull at 130–135°F for medium-rare and rest 10 minutes. Past 140°F there is no marbling left to cover for you. |
Low heat, then a knife. A 250°F oven or a 131°F water bath both work because both give you time to land on a narrow window on purpose; a hot oven does not. Grilling survives only in the London broil form, where the recipe ends in thin slices and covers for the heat. Whatever the method, carve at a right angle to the grain — on this muscle that decides as much as the temperature did.
Common questions
Why did my top round come out tough?
Usually the knife, not the oven. The fibres run the length of the muscle in one direction, so cutting parallel to them hands your teeth full-length strands to shear; cutting across leaves them a few millimetres long. The other cause is going past medium-rare, where the fibres tighten and there is no fat to make up the loss.
What is the difference between top round and bottom round?
They are the inside and the outside faces of the same hind leg — top round is the semimembranosus, bottom round the biceps femoris. "Top" and "bottom" describe where they sit on the hanging carcass, not on your roast. The outside face works harder, so bottom round carries more connective tissue and wants a braise.
Is top round the same as sirloin tip?
No. Sirloin tip, also called the knuckle, is the quadriceps group at the front of the leg where it meets the sirloin — a separate set of muscles with a different grain direction. Both are lean and both are cheap, which is why they get swapped, but the tip has more seams running through it and does not slice as cleanly.
Does marinating actually tenderise it?
Barely. Marinade moves a few millimetres into meat no matter how long you leave it, and acidic ones mush the surface before they reach anything. Salt is the only common ingredient that travels, and it takes hours. Marinate for flavour on the outside; get tenderness from the temperature and the slice.
