If you are new to cooking on your Weber Q then in this recipe I am going to teach you how to make the most perfect, juicy Weber Q roast lamb with crackling that you have ever tasted.
Yes! The weekend is finally here, and you have your family and friends around for the weekend. Oh, but wait. What are you going to cook?
If you are one of the lucky few that happen to have a Weber Q sitting on their back patio, then your in for a treat.
By reading my step by step guide until the end, you will have nailed juicy Weber Q roast lamb every time.
If you have never cooked lamb in your Weber Q then FEAR NOT!
My method is flawless and will make you a hit with your friends and family.
How to Prepare your Weber Q for Roasting?
A Weber Q is effectively a BBQ and an oven. But are also two completely different styles of cooking. It is important to remember this.
So to cook a Weber Q roast lamb effectively without burning the bottom of your meat, you will need to convert your Weber into a convection oven.
To do this, you will need what is called a convection tray made from aluminium, and you will also need a trivet to lift your meat above the convection tray so heat can circulate the meat.
The holes in the convection tray are so the fat, can escape and drip through the hole at the bottom of Weber Q.
Before placing anything onto the grill, make sure your Weber Q is clean. If you have a lot of fat build-up, it can become unsafe and cause a fire.
Check and clean your grill, change your drip tray and check to make sure the large hole at the bottom is clear of any fat build-up.
There are four grooves on the grill two on each side. Make sure to place the convection tray into those grooves, so the tray doesn’t move around.
Then place the trivet in the middle of the convection tray.
Next, we want to move on to preheating our Weber Q BBQ.
How to preheat the Weber Q?
There are two different Weber Q models, one that has a temperature gauge, and the other does not.
So how do we tell the temperature of our Weber Q?
We need to have something like what I have called the iGrill. This great little tool is a must-have for anyone with a Weber Q.
You must know the temperature of your Weber at all times. Otherwise, you could essentially burn your meat.
The iGrill 2 comes packaged with two probes.
Probe one is placed on the convection tray inside your Weber. This will tell you the temperature of the bbq.
And probe two is inserted into the centre of your meat, giving you direct access to the lamb internal temperature.
Then you can sit back pick up your phone and check the temps of both the Weber Q and the meat without leaving your seat.
If you would love to just sit and relax with a beer, and let your Weber Q do all the work, then you owe it to yourself to grab an iGrill 2 Meat Thermometer.
Now it’s time to fire up your Weber Q by turning both gas control knobs to the Start/High position and pressing the red ignition switch until you hear the gas going.
The lid must be closed at times during the preheating and cooking process.
Preheat the bbq for at least 10 to 15 minutes before placing your roast lamb into the Weber Q.
It’s time to make some yummy lamb crackle!
Once your Weber Q has been preheated, we need to turn down the small control knob to the low position, after all, we don’t want to charcoal our meat.
Next, place your lamb onto the centre of the trivet, and listen to it sizzle hmmm.
If you have a meat probe, insert it into the centre of the meat.
If your lamb has a bone, make sure not to let the probe touch the bone otherwise the internal temperature of the meat will give you a false positive. In other words, it won’t be accurate.
The reason we cook the Weber Q roast lamb at such a high temperature for a short time is to begin to get the skin to crackle quickly.
If the temp is too low when putting in our meat, it will not have enough heat to crackle the skin. Instead, it will be soft and rubbery during the cooking process.
Continue to cook with the small knob on the low setting and the large knob in the high position for 25 to 30 minutes. Please try not to be tempted to lift the lid during this time.
Trust your Weber Q to do its job.
What is the roast setting on a Weber Q?
After you have blasted your lamb with heat, we need to turn it down.
You will want to turn off the small control knob completely. And turn down the large control knob to the medium setting.
Provided your Weber Q is not out in the open air on a windy day, you should not need to change this setting again.
But just in case there is a lot of fluctuation in the temperature, you can adjust the roast control knob between the HI/MEDIUM setting to keep the temperature within the ballpark of where it needs to be to roast.
What is the roasting temperature on a Weber Q?
If you have an iGrill 2 meat thermometer, then this will be easy for you to monitor.
The Weber Q was never designed to be like the Weber kettle where you can roast at temperatures as low as 170°C to 180°C
This bbq needs heat to do its job correctly.
To successfully achieve a juicy Weber Q roast lamb, you need to maintain the temperature between 190°C to 230°C at all times. Or 375°F to 450°F.
You should also make sure to keep the Weber out of the wind and the elements, as this will cause it to struggle to maintain its correct temperature.
And you will often find yourself battling to keep the temp within this zone if left in the elements.
Can I roast vegetables in a Weber Q?
Absolutely! And I encourage it. Especially if you are lucky enough to own the medium and family series bbq.
That smokey aroma that comes from the lamb will be absorbed into your vegetables, giving them a unique and subtle smell and flavour.
I tend to add my potatoes and pumpkin when the internal temperature of the meat is at about 45°C or 113°F.
If adding vegetables, make sure to add them as quickly as possible to the trivet and close the lid as not to let a lot of heat escape.
Remembering to bring the roast control setting back up if required.
How long does it take to cook a Weber Q roast lamb?
To know the time it takes to cook a Weber Q roast lamb is dependent on its weight and thickness.
I go by either method. This takes me back to when I talked earlier about the importance of having a meat probe in your arsenal.
Because honestly if you have one of these, it doesn’t matter. A roast of any kind will cook when it cooks.
But to give you an example: If I have a roast that weighs approximately 2 ½kg then I know I am going to be looking at about 2 ½ hours to cook.
It is generally 1hr of cooking time to every 1kg of weight. This method worked for me in my Weber kettle days because I was cooking my roast lamb at around 180°C.
But trying to do this method on a Weber Q is impossible, because of the higher temperatures it will cook your meat. The Weber Q was never designed to cook meat at such low temperatures.
The other method is to measure the thickness of the meat. We do this because meat absorbs heat from the outside to its core. Theoretically the thicker the meat, the longer it will take to cook.
Place a ruler at the large and thickest part of the lamb. Make a note of the measurement and do some quick maths.
For every millimetre, you add one minute of cooking time. For example, if a lamb roast was 110 millimetres thick, it would take about 110 minutes of cooking time.
I tend to not worry about doing this and rely on my iGrill meat thermometer.
I always allow extra time to preheat, blast the skin for 25-30 minutes and finally, the roasting faze. And I still manage to have my roast rested and served before 6 pm, after starting the whole process at about 2:30 pm.
What should the internal temperature of roast lamb be?
Always be mindful of the internal temperature of your Weber Q roast lamb, it is white meat and if consumed while undercooked can make you sick.
A Weber Q roast lamb is safe to take out of your Weber Q when the internal temperature reaches a minimum of 60°C or 140°F which is considered rare.
- Rare 60°C
- Medium rare 60–65°C
- Medium 65–70°C
- Medium well done 70°C
- Well done 75°C
Source: Australian Lamb
Allow 15 to 20 minutes to rest as the internal temperature will begin to rise another 3°C during the resting process.
Another way to be sure the meat is cooked perfectly is to make an incision into the side and check if the juice is running clear.
The best part is carving your Weber Q roast lamb!
Like the title above says, this is the best part.
If you have followed my steps correctly, you should have a delicious, juicy lamb roast when you begin carving into it. Your tastebuds will be on overload.
This is the love the Weber Q provides, and I don’t know if I can ever go back to my Weber kettle.
If you had a go at cooking a Weber Q roast lamb, then please let me know how you went in the comments.
If it didn’t work out for you, then I am more than happy to help you figure out where it went wrong.
You can also check out my UlTIMATE WEBER Q GUIDE HERE! Where you can learn everything there is to know about cooking on your Weber Q BBQ.
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Weber Q Roast Lamb with Garlic and Rosemary
- 2.5 kg Bone In Leg of Lamb
- Rosemary Fresh
- Garlic Fresh
- Olive Oil
- When you are ready to start you will need to get your Weber Q ready for convection oven cooking. Place a new convection tray onto the grill, noticing that Weber Q trays will line up with the holes on the grill, this will prevent movement. Then place a trivet on top of the convection tray.
- Turn on the gas bottle that is connected to your Weber Q and turn both control knobs to the START/HI position. Then push the ignition switch to fire up the BBQ. If you have a Weber Q Baby then turn the control knob to START/HI. If you have 2 meat probes handy, then this is the time to rest the first probe onto the convection tray. This will give you the temperature of the Weber Q BBQ. Run at this setting for 10-15 minutes to get the Weber Q nice and hot, with the lid closed.
- While your Weber Q is heating up, now is the time to prep your leg of lamb. Begin by pealing and cutting fresh garlic cloves into small 1cm pieces. You will need about 12-14 small blocks of garlic.
- Cut 12-14 small pieces of fresh rosemary.
- Make 12-14, 2cm cuts across the lamb and place 1 piece of sliced garlic and rosemary into each insicion. Making sure to bury the garlic but leave a small amount of rosemary sticking out, so as to remove it later upon serving.
- Baste olive oil over the leg of lamb making sure the entire leg is covered.
- Sprinkle salt and pepper as desired.
Roasting the Leg of Lamb
- Place the lamb onto the centre of the Trivet, and if the Weber is hot enough you will hear it sizzle. Now is the time to insert your other meat probe into the centre of the lamb. If your roast has a bone, make sure the probe does not make contact with it, as this will give you a false internal temperature reading. Make sure you remember to close the lid to stop heat from escaping.
- If you have the Family Q series turn down the small control knob to the LOW position and leave the large control knob in the HI position. If you have a Weber Q Baby then don't change any positions on the control knob and continue with this method. Leave your leg of lamb for at least 25 to 30 min at this setting and please avoid the temptation of lifting the lid to check if the lamb crackle process has begun.
- After 30 minutes the lamb will already show signs of crackle. Next, you need to turn the smaller control knob to the OFF position, and the large control knob to the ROAST (middle) position.For the Baby Q, simply turn the single gas control knob to the medium (middle) roast position.
- The temperature will be high at first but turning the control knob to the medium position will soon bring the temperature down. And don't worry you won't burn the roast. Keep the roast at between 190°C to 230°C or 375°F to 450°F at all times. You can maintain this easily by keeping an eye on your temperature and adjusting the control between HI and Medium as required.
- Once the internal temperature of the lamb has reached 45°C or 113°F, it is time to add any vegetables that are required for roasting. Place your vegetables around the roast lamb, so they can absorb the smokey aroma and flavors of the roast lamb.
- Monitor the temperature of the Weber Q and meat throughout the cooking process with your meat probe. Once the internal temperature of the lamb has reached 155°F or 68°C lift the lid and remove the meat probe, making sure to wear gloves so as not to burn yourself. Place the lamb onto a serving plate and set aside to rest for 15 to 20 minutes. This will bring the internal temperature to around 160°F or 71°C. After resting carve your lamb and serve with roast vegetables and ENJOY!