In short
A rib of beef is the Christmas roast an Aga does best. Give the joint a hard start in the roasting oven to brown the fat, finish it gently, rest it properly, and the heat stored in the cast iron does the rest. Below is the method we use at home, with timings for every size of joint, the temperatures that matter, and the order of work that gets everything to the table hot.
Buying the joint
Ask your butcher for a bone-in fore rib, sometimes sold as rib of beef or standing rib. Two bones is about 2.5 kg and feeds five or six; three bones is 3 to 3.5 kg and feeds seven or eight, with cold beef for Boxing Day. Allow 400 to 500 g per person on the bone.
Look for a thick, creamy fat cap and meat with fine marbling. Beef that has been dry aged for 28 days or more has a deeper flavour and roasts more evenly. Ask the butcher to chine the joint (cut through the backbone) so the ribs come away easily when you carve.
Which Aga oven to use
Every Aga cooks a rib of beef in two stages, and the ovens are laid out for it:
- Roasting oven, 200°C to 240°C. The hottest oven, for browning the fat and sealing the outside. Our Aga oven temperature guide explains how each oven holds its heat.
- Simmering oven, 110°C to 120°C. Gentle, even heat from all sides. A joint moved in here cannot dry out or catch, which makes it the most forgiving way to finish a large piece of beef on a busy day.
On a 2-oven Aga you have exactly these two ovens. On a 3-oven or 4-oven model you can use the baking oven at 140°C to 180°C as a middle path, and the warming oven to hold plates and the finished beef.
Timings per 500 g
All timings assume the joint has been out of the fridge for one to two hours and has had 20 minutes of browning in the roasting oven first. They are a guide: a thermometer is the only sure way to judge a joint this size.
| Finish | Roasting oven, lower runner, per 500 g | Pull from the oven at | After resting |
|---|---|---|---|
| Rare | 15 minutes | 50°C | 55°C |
| Medium rare | 18 minutes | 55°C | 60°C |
| Medium | 20 to 22 minutes | 60°C | 65°C |
So a 3 kg rib for medium rare is 20 minutes browning plus about 1 hour 50 minutes, then 45 minutes resting. For the simmering oven method, see below.
Checking the internal temperature
Push a probe thermometer into the thickest part of the meat, away from the bone. The temperatures above are the ones to take the joint out at. During the rest the centre rises by around 5°C, so a joint pulled at 55°C serves at 60°C, a proper pink medium rare.
Step by step: rib of beef in the roasting oven
- Bring it to room temperature. Take the beef out of the fridge one to two hours before cooking and pat it dry. Cold beef roasts unevenly.
- Season generously. Salt and coarse black pepper all over, pressed into the fat. A thin smear of English mustard on the fat is a Yorkshire habit worth keeping.
- Make a trivet. Halve two onions and lay them cut side down in the roasting tin with a couple of carrots. The joint sits on these, which stops the base stewing and starts your gravy.
- Brown it. Put the tin on the floor of the roasting oven for 20 minutes. The fat should be crackling and golden.
- Finish it. Move the tin to the lowest set of runners in the roasting oven and cook for the time in the table, basting once halfway.
- Check it. Probe the centre. Take it out 5°C before your target finish.
- Rest it. Lift the beef onto a warm board, cover loosely with foil and leave it for 30 to 45 minutes. Keep the tin and its juices for the gravy.
The simmering oven method
If you would rather not watch the clock, use the simmering oven. Brown the joint on the floor of the roasting oven for 20 minutes as above, then move the tin straight into the simmering oven. At 110°C to 120°C the beef cooks slowly and evenly from every side, the fat renders gently, and nothing can burn.
A 3 kg rib takes roughly 2 to 3 hours to reach medium rare this way. Start checking with the thermometer from the 2 hour mark and take it out at 55°C. The rest is the same: 30 to 45 minutes under foil. The joint is noticeably juicier than a fast roast, and the roasting oven is free for everything else all afternoon.
This is also the method that rescues a Christmas morning. If the beef is running ahead, move it to the simmering oven early and it will hold without harm; if it is running behind, the roasting oven lower runner catches it up.
While the beef rests: trimmings and gravy
The 45 minute rest is not dead time. The roasting oven is empty and at full heat, which is when the roast potatoes go in on the floor and the Yorkshire puddings go in on the top runners. Our topside beef guide covers both, plus seasonal vegetables.
For the gravy, pour off most of the fat from the tin, leaving the onions and the dark juices. Put the tin on the simmering plate, stir in a tablespoon of flour, cook it for a minute, then add a glass of red wine and let it bubble. Top up with beef stock, scrape the base of the tin, and let it reduce while the beef finishes resting. Strain it into a warm jug and add any juices from the carving board.
Carving a rib of beef
Stand the joint on the board with the bones upright. Run a long knife down between the meat and the bones to free the meat in one piece, then lay it fat side up and carve across the grain in thick slices. Put the bones back in the tin: they make an excellent stock for Boxing Day soup.
Christmas timing plan
For beef on the table at 2 pm, roasting oven method, 3 kg joint for medium rare:
- 11.00 Beef out of the fridge. Potatoes peeled and parboiled.
- 11.40 Beef into the roasting oven floor to brown.
- 12.00 Beef to the lowest runner.
- 13.10 Probe the beef. Out at 55°C and onto the board to rest.
- 13.15 Potatoes into the roasting oven floor. Gravy started on the simmering plate.
- 13.40 Yorkshire puddings in at the top of the roasting oven.
- 14.00 Carve and serve.
Using the simmering oven method, the beef goes in to brown at 10.40, into the simmering oven at 11.00, and everything else is the same from 13.10.
Leftovers
Cold rib of beef is one of the best things about Boxing Day. Slice it thinly for sandwiches with horseradish, or warm slices gently in the gravy in the simmering oven rather than in the roasting oven, which dries it out. The bones and trimmings make a rich stock in the simmering oven overnight.
Frequently asked questions
How long does a rib of beef take in an Aga?
Give it 20 minutes in the roasting oven to brown, then allow 15 minutes per 500 g for rare, 18 minutes per 500 g for medium rare or 20 to 22 minutes per 500 g for medium, plus 30 to 45 minutes resting. A thermometer is more reliable than the clock: pull the joint at 50°C for rare, 55°C for medium rare and 60°C for medium.
Which Aga oven do I cook rib of beef in?
Start it in the roasting oven, the hottest oven at 200°C to 240°C, to brown the fat and seal the outside. Finish it there on a lower runner for speed, or move it to the simmering oven at 110°C to 120°C for a gentler, more forgiving finish.
Can I cook rib of beef in the simmering oven?
Yes, and it is the most relaxed way to do it. Brown the joint in the roasting oven for 20 minutes, then transfer it to the simmering oven. A 3 kg joint usually takes 2 to 3 hours to reach medium rare; check with a thermometer from the 2 hour mark.
How much rib of beef do I need for Christmas?
Allow about 400 to 500 g of bone-in rib per person. A two-bone rib of around 2.5 kg feeds five to six; a three-bone rib of 3 to 3.5 kg feeds seven or eight with leftovers.
Should rib of beef be cooked on or off the bone?
On the bone. The bones protect the meat, keep it moist and add flavour, and they make the joint easier to carve once rested: cut the meat away from the bones in one piece, then slice across the grain.
How long should I rest a rib of beef?
At least 30 minutes, and 45 minutes for a joint over 3 kg, loosely covered with foil. The temperature carries on rising by about 5°C as it rests, and the juices settle back into the meat. A rested joint carves cleanly and keeps the Christmas table waiting for nothing.
Cook with confidence this Christmas
If your Aga is struggling to hold its heat, or you would like the ovens to be ready at the touch of a button on Christmas morning, we can help. We service and repair Agas across Yorkshire, Cumbria and the North East, and we fit electric conversions that give you independent control of each oven. Call us on 01748 811030 or request a callback below.