Flat brisket is the lean, even slab of the brisket, and it rewards patience more than any other beef cut. Cook it hot and fast and it is like chewing a belt; cook it low, slow and covered and it slices into soft, beefy ribbons that hold together for a Sunday plate or a proper salt beef sandwich. This guide covers how to cook flat brisket in the oven, slow cooker and on the BBQ, with a flat brisket cooking times table by weight, the temperature to aim for and how to slice it.
What is flat brisket?
Brisket comes from the lower chest of the animal, a hard-working muscle full of flavour and connective tissue. A whole brisket is two overlapping muscles: the flat and the point. The flat (sometimes called the first cut) is long, leaner and an even thickness, with a fat cap on one side. That even shape is why it cooks evenly and carves into neat slices. The point is thicker, fattier and better for pulling. Our Flat Brisket 1.5kg is a 1.5kg flat; if you want a smaller, rolled and tied piece, the Brisket Joint 1kg uses the same low-and-slow methods. For more on the two muscles, read what is beef brisket: point and flat.
Before you cook flat brisket
Take the brisket out of the fridge an hour before cooking and pat it dry. Season it well all over with salt and black pepper; if you have time, salt it the night before and leave it uncovered in the fridge, which seasons the meat deeper and helps the crust. Leave the fat cap on. It bastes the lean flat as it renders, and you can trim any excess after cooking.
How to cook flat brisket in the oven
- Heat the oven to 150°C (130°C fan, gas 2).
- Brown the brisket all over in a hot casserole or roasting tin with a little oil or dripping, about 8–10 minutes. This builds flavour for the gravy.
- Lift it out, soften a couple of sliced onions and carrots in the fat, then add about 500ml of beef stock (or part stock, part ale or red wine).
- Sit the brisket on the veg, fat side up, with the liquid about a third to halfway up the meat.
- Cover tightly with a lid or a double layer of foil and braise for about 4–4½ hours for a 1.5kg flat, turning it once halfway.
- Test the thickest part: a probe or fork should slide in with almost no resistance. If it still resists, give it another 30 minutes.
- Rest it, loosely covered, for 20–30 minutes while you skim the liquid and reduce it into gravy.
For a darker, barky finish without a smoker, rub the flat with salt, pepper and smoked paprika, wrap it tightly in foil with a splash of stock and cook at the same temperature, opening the foil for the last 45 minutes. Our full brisket in the oven guide has both versions with an ingredients list.
Flat brisket cooking times
These are guide times for a fridge-cold flat brisket, cooked covered or wrapped. Brisket is done when it is tender, not when the clock says so, so start checking 30 minutes early and keep going if it still resists. Most cooks look for around 90–95°C in the thickest part for slicing.
| Method | Temperature | 1kg | 1.5kg flat | Ready when |
|---|---|---|---|---|
| Oven braise, covered | 150°C (130°C fan, gas 2) | 3–3½ hours | 4–4½ hours | Probe slides in, about 90–95°C |
| Oven, foil-wrapped dry rub | 150°C (130°C fan), uncover last 45 min | 3–3½ hours | 4–4½ hours | Probe slides in, about 90–95°C |
| Slow cooker | Low | 8 hours | 9–10 hours | Fork-tender, slices or pulls |
| Slow cooker | High | 5 hours | 6 hours | Fork-tender, slices or pulls |
| BBQ or smoker, indirect | 110–130°C, wrap once the bark is set | Go by feel | Allow 5–7 hours | Probe slides in, about 90–95°C |
How to cook flat brisket in the slow cooker
Brown the brisket first if you can; it is not essential, but it gives the gravy colour and depth. Lay sliced onions and carrots in the slow cooker, sit the flat on top fat side up, and pour in about 300ml of hot stock. That is enough: a slow cooker loses very little liquid and the brisket releases its own juices. Cook on low for 9–10 hours for 1.5kg, or on high for about 6 hours. A 1.5kg flat may need cutting in half to fit a smaller pot. Lift it out, rest it, and thicken the liquid in a pan. Full steps are in how to cook brisket in the slow cooker.
Smoking or barbecuing a flat brisket
Set the barbecue up for indirect heat at around 110–130°C, with the coals or burners to one side and the brisket on the other, fat cap up. Cook it until the outside has a dark, set bark, then wrap it tightly in foil or butcher paper with a splash of stock to push it through the stall, the point where the internal temperature sits still for a while as moisture evaporates. Allow roughly 5–7 hours for a 1.5kg flat, but go by the probe and feel, not the clock, and rest it wrapped for at least 30 minutes.
How to slice flat brisket
Look at the cooked flat and find the lines of muscle fibre running along it. Slice across them, at right angles, about pencil thickness (around 5mm). With the grain gives you long, stringy strands even when the cook was perfect. If the brisket is so tender it falls apart when you slice it, do not worry: pull it into chunks and spoon over the gravy.
What to serve with flat brisket
For a Sunday roast, serve sliced brisket with roast potatoes, greens and the braising gravy, or try our brisket pot roast with gravy. For something different, pile it into soft rolls with mustard and pickles, or use the leftovers in brisket chilli with rice. Our main how to cook beef brisket guide covers the rolled joint, and best beef for slow cooking compares brisket with the other cuts in slow cooker meat.
Leftovers and storing cooked brisket
Cool leftover brisket quickly and keep it in its juices in the fridge for up to 2 days, or freeze it in its gravy. Reheat gently, covered, until piping hot all the way through, and only reheat once.
Flat brisket FAQs
How long does a 1.5kg flat brisket take in the oven?
Braised and covered at 150°C (130°C fan, gas 2), a 1.5kg flat brisket takes about 4–4½ hours. A 1kg piece takes about 3–3½ hours. It is ready when a probe or fork slides into the thickest part with almost no resistance, usually around 90–95°C inside.
What temperature should flat brisket be cooked to?
Brisket is safe long before it is tender. For slicing, most cooks take a flat to around 90–95°C in the thickest part, where the connective tissue has melted. Go by feel as much as the number: the probe should slide in like it is going into soft butter.
Should you cook flat brisket covered or uncovered?
Covered for most of the cook. A lid or a double layer of foil keeps the moisture in so the lean flat does not dry out. Take the cover off for the last 30–45 minutes if you want a darker crust on the fat cap.
How long does flat brisket take in a slow cooker?
About 9–10 hours on low or 6 hours on high for a 1.5kg flat, and about 8 hours on low or 5 hours on high for 1kg. You may need to cut a 1.5kg flat in half to fit a smaller slow cooker. Low gives the more tender result.
What is the difference between flat brisket and point brisket?
The flat is the long, leaner, even-thickness muscle of the brisket, so it cooks evenly and slices neatly. The point sits on top of it at one end and is thicker and fattier, which makes it better for pulled beef and burnt ends.
Why is my brisket tough?
Almost always because it is undercooked rather than overcooked. Brisket goes through a firm stage before the collagen melts, so give it another 30–60 minutes covered and test again. Slicing with the grain instead of across it will also make well-cooked brisket chewy.
