Juicy Weber Q Roast Lamb with Garlic and Rosemary

If you're a novice to cooking on your Weber Q, then you're in for a treat. This recipe will guide you step-by-step on how to make the most delectable and juicy Weber Q roast lamb you've ever tasted. Whether you're planning a special occasion or just looking to impress your guests, this dish is sure to steal the show.

Hooray, the weekend has arrived, and you have guests over! But what's on the menu? If you own a Weber Q, you're in luck. Follow my detailed guide and discover how to make mouth-watering Weber Q roast lamb that will impress your guests every time.

Don't worry if you're new to cooking lamb on your Weber Q, my foolproof method will make you a pro in no time. With juicy results every time, this recipe is sure to be a hit with your friends and family. Keep reading to learn how to master the art of Weber Q roast lamb.

How to Prepare Your Weber Q for Roasting?

A Weber Q is a versatile cooking appliance that combines the functionalities of a BBQ and an oven. However, these two cooking styles are vastly different, and it's crucial to keep this in mind while using it.

To cook the perfect Weber Q roast lamb without burning the bottom, it's essential to transform your Weber Q into a convection oven. This conversion will ensure even cooking and allow the meat to cook to perfection.

To convert your Weber Q into a convection oven, you'll need an aluminium convection tray and a trivet to elevate the meat above it, allowing heat to circulate. The tray features holes that allow fat to escape and drip down through the bottom of the Weber Q.

Before placing any food on the grill, ensure your Weber Q is clean. Excessive fat build-up can pose a fire hazard. Clean your grill, replace the drip tray, and ensure that the bottom hole is clear.

The grill features four grooves, two on each side. Place the convection tray into these grooves to prevent it from moving around. Then, position the trivet in the centre of the tray.

Now it's time to preheat your Weber Q BBQ before cooking.

How to preheat the Weber Q?

To preheat a Weber Q, you should follow these steps:

1. Make sure the grill is clean, and the drip tray is empty.
2. Open the lid and turn on the gas supply.
3. Turn both gas control knobs to the Start/High position.
4. Press the red ignition button until you hear the gas flowing.
5. Close the lid and let the grill preheat for at least 10 to 15 minutes.
6. Check the temperature gauge or use a digital meat thermometer to confirm the grill has reached the desired temperature before placing any food on the grill.

It's important to note that the preheating time may vary depending on the model and size of your Weber Q, as well as the desired cooking temperature. Always refer to your Weber Q owner's manual for specific preheating instructions.

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're fortunate enough to have the Weber Q medium or family series BBQ.

If you're cooking a succulent roast pork, lamb, or chicken on your Weber Q, why not add some potatoes and pumpkin on the side? I always do, and it's a game-changer!

The savory and smoky flavors from the lamb will seep into the veggies, giving them a delicious and unique taste.

But timing is key here. I suggest adding your veggies to the trivet when the meat's internal temperature reaches around 30°C or 86°F.

Don't take too long adding the vegetables as it will let the heat escape, and you don't want that. So, quickly put them in and close the lid.

And one more thing, don't forget to adjust the roast control setting if needed, depending on the quantity of vegetables you've added.

Trust me, your taste buds will thank you!

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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