Use BBQ for both searing and slow-roasting beef

Question

When I make roast beef in the kitchen I typically have these two cooking steps:

1. Sear on all sides in a frying pan on high(ish) heat;
2. Slowly roast it in the oven on low(ish) temperatures.

I've varied the temperature in step 2 from 160 degrees celsius down to 80 degrees (about the lowest temp my oven can consistently provide). I've found that the closer (lower) I get to 80 degrees, the better the result.

I want to bring this process to my BBQ now, preferably doing both steps using the BBQ itself. I'm unsure how to deal with the fact that the BBQ should be rather hot for step 1, yet a lot cooler for step 2.

From experience I know that the heat I'd want for step 1 would at a minimum lead to 180 degrees on my BBQ when the lid goes on (or higher if I'd fail to reduce air flow).

The only workarounds I could think of:

• Do step 1 in the kitchen with a frying pan (feels like cheating / will reduce BBQ-flavor);
• Do step 1 on a lot of coal, and remove some coal before moving to step 2 (feels wasteful);

Do you guys have any suggestions on how to handle this?

Some more details:

• I have a Weber BBQ with lid and built-in temperature monitor;
• I have a meat thermometer to measure the core temp of the meat as it roasts;
• I use indirect heat for step 2 by having the coal on the sides and the meat in the middle, and intended to use direct heat in step 1 by placing the meat over one of the sides;
• I have a chimney to quickly get fresh coal started;

Answer 1

In the Good Eats episode on tuna, Alton Brown mentioned that you want as hot of a fire as possible, and that you could cook directly over the chimney starter, once the coals are going:

As for the fire, well, it's hot. It's real hot. Just take a look. It's like a jet engine down there. Now the normal thing to do would be to distribute those coals across the bottom of the grill and get to cookin'. But, um, I don't want to dissipate the heat. I don't want to spread it out. I want to keep it concentrated. I want to cook on a jet engine! And ... it's ... my jet engine so I say we'll cook on the jet engine.

He then put a grate over the top of the chimney starter, and cooked his tuna.

In your case, you could sear the outside of the roast, move it to the side, then dump the coals into your grill for a two-level fire, and then put the meat over on the cold side. It's not all that different from what you were already doing, but it should give you a hotter initial sear.

Answer 2

You have 2 ways of controlling heat in a kettle bbq, they are fuel quantity and airflow. Reducing the amount of fuel which can combust at any one time will lower the amount of heat the bbq can produce at full airflow. Reducing airflow by partially closing the air valves will reduce the amount of heat the fuel can produce no matter how much fuel you have in it. You'll want to use a combination of the two.

One approach to this would be to put a pile of lit charcoal in one end of the bbq, sear the meat, then move the meat to the indirect side, cover and significantly close down the airflow to cool the fire. The problems with this method are that you may have so little air for the fuel that it may simply go out, and that you would get inconsistent heat from the fuel and a big drop in heat at some point as the fuel burns out. You'd need to be tweaking your airflow constantly to keep this going as it's unpredictable, so it's not ideal.

When doing low and slow a good method is to make a C shape of charcoal and start one end of it, then cover and let it go - the charcoal burns through the C from one end to the other and gives a nice even and consistent heat. I'd suggest modifying this a bit, instead having a C shape with a fat end. You'd start on high heat, ie the fat end of the C, then once that burns out the tail of the C would be lower heat. You may have to shift the meat around a bit once or twice to keep it off the direct heat during the low and slow period, and some tweaking of the valves to get the right temperature, but that's about it. You could leave it unattended for awhile using this method.