Thoughts on the workings of charcoal and getting a perfect sear

[CeramicTool]

I have had a lot of questions about charcoal and how to master it. I think I have developed a decent grasp of the situation and looking for some advanced input to take my cooking to the next level.

Fire needs three things in my kamado: Oxygen, Heat, Charcoal. On my very first cook I put the approximately appropriate amount of charcoal (only a small amount! lol) in the cooker and left the vents wide open to achieve a temperature of 250. A lot of work, not very stable. Definitely doable, but I wouldnt recommend it. Then I learned to just fill the cooker right up with charcoal!

The next Question I had was when is the charcoal lit, and how does the fire travel if the charcoal isnt touching? A: The charcoal is lit when the charcoal reaches a certain temperature over an area large enough that the heat cant be disapated away (through conduction) faster than the chemical reaction just started. This is why it only takes a quick hit with the Looftlighter when the charcoal has recently been extinguished to get it going again, and why it takes a lot longer in -30c weather. Just like a slab of meat sucks the heat out of the grill, so too do the surrounding charcoal.

What causes nasty smoke and how can I top up my grill without creating it? Nasty smoke is created when the system is out of equilibrium. It starts out of equilibrium because its cold with a hot spot. This causes heat to be wicked away, which means the temperature of the charcoal is lower than it otherwise would be. The environment is stealing heat, causing an inefficient burn that leaves nasty smelling stuff unburnt. Slowly, as the differential between the Komado and charcoal temperatures reduces, the fire gets more efficient and produces less nasty smoke. Eventually, the Kamado will reach thermal equilibrium, and clean, but just slightly smoky smoke will be the byproduct of the system. This is what I want.

Every deviation from this equilibrium will create a sub-optimal smoke. Opening the lid feeds excess oxygen to the charcoal, raising the temperature. When the lid is closed and the oxygen flow is reduced back to normal the charcoal bed is still hotter than it should be for the amount of oxygen it has to burn. This form of oxygen deprivation will bring the system out of equilibrium and create sub-optimal smoke until the heat has a chance to disapate and settle back to equilibrium. The same goes for putting something cold in the grill, like a large cut of meat or a water tray. The heat will migrate towards the coldest part and the system is out of equilibrium. As the meat/water warms up, and the grill is brought back up to temperature, equilibrium is again established. The reason throwing meat on the grill usually doesn't do this is that the excess heat created by opening the lid is counterbalanced by being able to travel to and end up in the cold meat/water and equilibrium is achieved faster than if only the lid were opened, or only cold food was put on the grill (without opening the lid). With a good heat soaked Komodo to provide heat to the cold meat/water, the smoke should stay clean in these above scenarios.

This neatly solves one of my beginner misconceptions: That brand new charcoal causes nasty smoke no matter what, and that pre-burned charcoal produces better smoke. This is somewhat true on its face, new charcoal DOES produce nastier smoke when first lit. It is denser and less porous. The energy available is high, but because it has a smaller surface area to volume (because less porous), it also is harder to light and takes longer to reach equilibrium. Because it takes longer to reach equilibrium, it produces nasty nasty smoke for longer. Preburnt charcoal has had a bazillion extra holes burnt through it and has a much larger surface area to volume which allows it to heat up faster. it also has a lower weight, so it reaches equilibrium faster because there is less material to heat up.

The easy workaround for this is to absolutely blast the charcoal at the beginning to generate a lot of heat, and then let the grill suck the heat out of the charcoal. A cold grill can be brought to equilibrium faster by guestimating how much to overshoot the fire on the initial light knowing that the heat will be sucked out and the charcoal will not be able to produce a runaway temperature.

From the above, I have some theories. Im too lazy to use a chimney starter and just make one small/medium fire in the center of the charcoal, maybe a little closer to the bottom vent than center. When it comes time to top up the grill with charcoal, I can do this a couple times preemptively If i wanted to keep the grill going indefinitely. I havent had this problem lately, so I havent been able to try this on-the-fly refilling method. A couple room temperature chunks at a time in an area that has already burnt away wont suck too much heat out to create nasty smoke, and putting them away from the ebbing and flowing lit charcoal allows the charcoal to gradually come up to temperature and light without creating nasty smoke by trying to light room temperature charcoal. Theoretically, I could create good smoke for an indefinite period of time with this method. Thoughts?

Which brings up another question I had, why is a chimney starter necessary? I think the short answer is that it is not, but that by getting the entire bed of coals going at a low clip that the grill temperatures will be more even and less erratic depending on where the fire below is travelling. This would also preclude topping up charcoal without creating nasty smoke though, there would be no safe place to put it without it catching on fire immediately and making bad smoke and taking a long time to equalize.

Which segues into my prime objective: How to create the Best Steak. One of the problems Im having is the Sear part of a reverse sear. Flare-ups cause an inoptimal smoke flavor. On the one hand, I need to sear, and sear fast so there is no large grey ring on a 1.2KG Striploin roast (yum!). On the other hand, the intense heat causes grease drips which cause fire and flareups and meat that sometimes ends up more Charbroil than Maillard. Some of the best successes I have had are using a hair dryer in a system to create something that I dont totally understand, but that may approximate an artificially high equilibrium. If I dont entirely fill my KJ mini I can use a hairdryer in the bottom vent and achieve a thermal equilibrium at a lower temperature than the usual 600-700-800-900 that would ensue with a full basket and blower. My best successes have come with an equilibrium of about 525-600f created using forced air. My theory is that flare ups make nasty smoke because the sudden heating caused by flareups brings the system out of equilibrium and makes bad smoke, not to mention the fire directly against the meat. Instead, I bring the grill to an artificially high equilibrium that relys on feeding it lots and lots of oxygen, which gives me the benefits of moisture wicking. As the steak sears, the moisture is wicked away more efficiently leaving the stuff from the juices naked and dry on the outside of the meat where it does its Maillard thing well. The fire still shoots out the top of the grill and touches my meat, but there seems to be a sweet spot where the rapid temperature increase of the meat provides a protective barrier of moisture that is constantly being wicked away without the steak catching on fire.

 

Hope this makes sense. I still feel like a beginner, but Im starting to be master of the fire. Any tips, tricks, suggestions, corrections are appreciated.

 

[jeffshoaf]

You seem to be having a lot of concern about topping up the charcoal mid-cook. If i may ask, why are you needing to do this? For a low and slow cook staying with a full charcoal basket, you should have no issue getting more than 16  hours without burning all your fuel aiming you're using a good quality lump. For any hot and fast cook (other than pizza), you should be able to get at least 5 or 6 hours from a full basket. For very hot cooks (800° in the dome) for pizza, etc., if you need to go more than a few hours, you may need to add a real pizza oven to your arsenal!

I can see adding charcoal to get a very hot temp to do a reverse sear, but I'd think the best method for that is to remove the steaks to rest, then removing the main gate, topping up the charcoal, and then opening the vents to ramp up the heat. You can then put the lower grate in for searing or, to get even closer to the fire, invert the top grate and it'll sit right down over the basket for searing. Since your steaks are out of the KK when adding the charcoal, you shouldn't get dirty smoke once the charcoal is up to searing temps and you avoid the issue entirely. Of course, unless you slow roasted you steaks overnight or you started with less than a full basket, you probably have enough charcoal let to get to searing temps without topping off.

Personally, I've given up on reverse searing for steaks -- i just can't seem to judge when to switch to searing to get the final internal temp I'm wanting. I sear first and then use a Meater or other leave-in thermometer to indirect grill to the desired doneness. I've moved to mostly using a Santa Maria grill and wood for bring steaks now, but when I did them on the KK, I'd bring the KK to searing temp and use the inverted upper grid to sear, then close down the vents and finish the steaks off on the main grate.

[CeramicTool]

Quote

 

Topping up is more for long brisket cooks so I can sleep through the night. Now that I have a Thermoworks Smoke and Billows, they seem to be more energy efficient and its not really an issue. But the question still remains, if I wanted to cook a brisket overnight and then keep the grill going the next day, how do i keep if going indefinitely? Its really more of a learning question than a practical question that has implications for many things.

As for steaks, thin cut are not appropriate for RS, so Im usually doing a 2 1/4" to 4" cut (anywhere from steak to small roast). I find 10-15f below target works well, but the smaller the steak, the harder to judge. The bigger the steak, the closer to 10f below I go. I get pretty good results. The problem is I have done a few truly amazing RS's before, and I need to be able to repeat that perfect turbocharged Maillard dark brown. Its not as easy as it looks. My main problem is I get the fattiest cuts I can, and they ooze fat out. For pork rib roasts with skin on, I have no choice but to sear first and get the cracklin going with all that fat. But for a fatty steak, I really want that crisp all around dark brown finish, and searing first, roasting second ruins the crispy crust.

[tony b]

You guys are making my brain hurt worse than a Syzergies dissertation!

It's just BBQ, not Rocket Science! 

[jeffshoaf]

34 minutes ago, CeramicTool said:

But the question still remains, if I wanted to cook a brisket overnight and then keep the grill going the next day, how do i keep if going indefinitely? Its really more of a learning question than a practical question that has implications for many things..

A few thoughts on this - thoughts only, not based on experience:

1.  Use a longer burning charcoal, like the KK extruded coconut charcoal. I know it's almost impossible to get the KK charcoal right now, but there are other extruded charcoals that claim longer burn times (B&B has one that's available in a lot of places - https://bbcharcoal.com/product/competition-char-logs/), as well as charcoal made from South American hardwoods (https://jealousdevil.com/products/). You may have seen a test where a reviewer ran one load of KK Coco char for several days at low and slow temps.

2.  In your original post, you ask about chimney starters; one use of these is to get the charcoal you're adding past the dirty smoke stage before adding to an existing fire. If you don't want to add a full chimney's worth to avoid raising the kk's temperature, you can start way less than a full chimney -- I usually use just a single layer of lump in the chimney to start my KK now (I've gone from using a Weed burner torch and parafin cubes starting charcoal directly in the KK to using the chimney now)

3. Preheat but don't light your additional charcoal before adding it to the KK - if heated almost to ignition, my understanding is that it ignites with little to no dirty smoke;  you touch on this on your original post. This is why snake and minion charcoal techniques used in kettle grills and big competition water smokers don't create dirty smoke issues. But how to preheat? I vaguely recall Dennis posting about this years ago but couldn't find anything with a quick search - maybe a pot full of charcoal on the main KK grate? On a gas grill?

 

 

Edited November 21, 2021 by jeffshoaf

[jeffshoaf]

6 minutes ago, tony b said:

You guys are making my brain hurt worse than a Syzergies dissertation!

It's just BBQ, not Rocket Science! 

One of the benefits/curses of retirement - time to obsess on stuff like this!

[braindoc]

Big fan of reverse searing.   For  cuts > 2 inches I’m looking for 105° F.  Usually, I’m doing this inside and will start in a 200° oven and finish on cast iron as hot as I can get it.  If the cut is not as thick I’ll take it out a few degrees lower.
 

Yesterday I cooked a 3 lb American Wagyu tri-tip from Hunts’ Point on my KK.  The grate temp was about 235°.  I took the meat off and got the temp up to about 475° and seared on the inverted top grate for a couple of minutes per side.

[CeramicTool]

3 hours ago, tony b said:

You guys are making my brain hurt worse than a Syzergies dissertation!

It's just BBQ, not Rocket Science! 

There is no such thing as "Just" BBQ. If you wish to argue, Ill have the moving truck pick up your KK and leave you a rusted out Wal-Mart BBQ 😜

 

[Poochie]

On 11/21/2021 at 3:00 PM, tony b said:

You guys are making my brain hurt worse than a Syzergies dissertation!

It's just BBQ, not Rocket Science! 

 

Said the future astronaut

[Syzygies]

On 11/21/2021 at 1:00 PM, tony b said:

You guys are making my brain hurt worse than a Syzygies dissertation!

We just enjoyed Thanksgiving with the family of a mathematician friend and colleague. There was no apple pie. A Lamaze recommendation to bring apples to her delivery left an impression on their adult daughter. Of course I recommended Cien años de soledad.

Great things can come from obsession. The waves are a gift. One needs to learn to surf.

The Beatles couldn't read sheet music. Cooking is learning to see the simple.

[Tucker]

I used to think traditionally about grilling steaks until I bought "Charred & Scruffed" written by Adam Perry Lang.

Unless a guest wants their steak, chop done on the grill (or they, eck, want it well done) I drop them directly onto the white-hot coals.

I get super crusty goodness, perfect sear and doneness (med-rare to rare).

The fat gets rendered wonderfully.

 

[C6Bill]

Simple reverse sear for Thanksgiving

 

 

[tekobo]

20 hours ago, Tucker said:

I used to think traditionally about grilling steaks until I bought "Charred & Scruffed" written by Adam Perry Lang.

I love Adam Perry's approach to layering flavour.  I always have a jar of his four seasons blend to hand - it is easy to make up and is great universal seasoning.  I have only "clinched" or cooked direct on coals a couple of times.  Sounds like I should try it again as that steak of @C6Bill's looks awesome!

[C6Bill]

@tekobo I cooked at 225f until I got an internal temp of 115. Then rested for 20 minutes with the vents opened up more to get good red hot coals. Then I tossed it in to sear 😁

[CeramicTool]

Ok. I like these answers.... just go hardcore on the direct Radiation and call it a day. Double the distance, 1/4 the radiation. But who needs that kind of math when you can just plop the steak on the coals.

[C6Bill]

KISS

[remi]

I like it- but would never have thought to do it... would've thought that putting the meat directly on the coals would have it covered with dust and ash? Or do you brush it off after- or does that not actually happen? And if not- how/why?

[tekobo]

9 hours ago, remi said:

I like it- but would never have thought to do it... would've thought that putting the meat directly on the coals would have it covered with dust and ash? Or do you brush it off after- or does that not actually happen? And if not- how/why?

Adam is very clear in his book that you need to get to the stage with hot coals, create a level bed and blow off the ash just before putting the meat on.  I want to try pork chops this way as I hope it will reduce smoking.  Some articles that came up on a quick google search: https://www.finecooking.com/recipe/clinched-strip-steak, https://www.cookinglight.com/cooking-101/meat-clinching-a-revelation-in-grilling and https://www.theguardian.com/lifeandstyle/2015/may/27/dirty-barbecue-dirty-steak-clinching

[tony b]

Alton Brown did a video cooking a steak underneath a charcoal chimney full of red, hot coals. The trick was to shake the chimney to get all the loose ash off before putting the steak underneath it. I was a bit leary of it, so the 1 time that I tried it, I put the steak on a grate on top of the chimney on the lower grate of the KK. Worked OK for getting a nice sear, post Sous Vide.

[remi]

13 hours ago, tekobo said:

Adam is very clear in his book that you need to get to the stage with hot coals, create a level bed and blow off the ash just before putting the meat on.  I want to try pork chops this way as I hope it will reduce smoking.  Some articles that came up on a quick google search: https://www.finecooking.com/recipe/clinched-strip-steak, https://www.cookinglight.com/cooking-101/meat-clinching-a-revelation-in-grilling and https://www.theguardian.com/lifeandstyle/2015/may/27/dirty-barbecue-dirty-steak-clinching

Thanks- I guess I shouldn't fear the dirt so much!