Thoughts on the workings of charcoal and getting a perfect sear

[tekobo]

I had a thin venison rump steak the other day and cooking direct on the coals seemed to be a good way to get a good sear quickly without over cooking the steak.  The soot that you see on the KK comes from blowing it off the embers before placing the steak on top.

The steak was cooked rare, to my liking, but I did find it just a little bit gritty on the outside.  I think it is a method worth pursuing and will try again soon.  

[tony b]

At least you tried it. I haven't done a caveman in a very long time. 

[C6Bill]

Doing be entire cook on the coals maybe the coals are cooling a little bit resulting in the little bit of grit ?

[CeramicTool]

On 12/2/2021 at 1:53 AM, 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

In the last couple months I have been trying different techniques, sous-vide and reverse sear with a special emphasis on getting a good sear. The above advice seems to tack with what I have been seeing.

At first, I was trying to get as hot a coal as I can, compliments of a hair dryer. This is how i stumbled on blowing the ash off before searing. Hotter isn't better though. I have found that the pit of coals should be of a natural disposition, which is to say at a natural equilibrium without the use of a fan, unless you plan on using the fan throughout the entire sear process, which creates an artificial equilibrium. It wasnt necessarily the blackness that was offputting about such a high heat (say 700-900f), or even the burnt pepper or garlic taste. I believe that supercharging the charcoal out of equilibrium causes it to burn less efficient and give a nasty smoke flavor.

Which has become a rule: when using forced air, allow the coals to settle back down to equilibrium before using.

As for the sear itself, I have found that letting the coals settle down, a quick blow with the hairdryer from below and above, and 5 minutes to stabilize at a temperature of 450-550 on my dome works best. I also use a kamado joe mini grate to sit down on top of the coals, giving an extra half inch or so of clearance from the coals. From there, I just turn when appropriate until seared to my liking.

I have found getting off the coals a touch allows for no grit from the ash, and less "heat suckout" from the meat using conduction to steal heat and turn charcoal from red to black.

I'm satisfied with my progress so far, but have advance plans to perfect the sear that improves on moisture wicking for more browning and searing. (hint: less charcoal, more airflow, artificial equilibrium, faster and better moisture wicking from surface of meat, less drippage and flairup, more brown, less black)

 

[tony b]

Looking forward to your next attempts and updates!

[LK BBQ]

This is interesting.  I always thought that the bad smoke was from different compounds in the wood having different smoke points - therefore black smoke before good smoke.  I vaguely remember doing wood distillation in the past to separate the different compounds.  Does anyone know if the different colored smoke is because of equilibrium issues or the different compounds?  

I will try the direct on the coals searing strategy one of these days!

 

[tony b]

@DennisLinkletter says that it's due to the volatile compounds that need to get burned off first to promote the "good" smoke (bluish in color). 

[swoff1]

On 11/21/2021 at 1:08 PM, jeffshoaf said:

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

Amen

[tekobo]

I am not retired so I need you folk to do the experimenting so I can benefit from your findings.  Looking forward to the next instalment @CeramicTool.  I don't have any pork chops to hand at the moment and so cannot try them out but they will be next on the list.  That or a lamb chop.  Both are fatty and prime candidates for testing this method.  

[Poochie]

Of course you're not retired. You're only around 25 years old. Whippersnapper!

[CeramicTool]

On 2/4/2022 at 9:42 AM, tony b said:

@DennisLinkletter says that it's due to the volatile compounds that need to get burned off first to promote the "good" smoke (bluish in color). 

I have done some extensive reading today to get to the bottom of this.

Much of the literature deals with wood fires and offset smokers, so here is a good "translation primer" to help fit these into the framework of a Komodo Smoker: https://kbq.us/bbq-edu-blog/how-wood-burns/

1. Drying – that log is full of water. Green wood has ~80% (of dry weight) moisture; a 9 lb log = 5 lbs wood + 4 lbs water. Seasoned wood has ~20%, so the same log split and dried for a year will weigh 6 lbs. There’s still a pound (pint) of water that must boil out before the log’s temperature will rise over ~230F. Dessication makes lots of steam that helps keep your meat moist; it also consumes a lot of heat from the fire.
2. Decomposition – once the log is dry, heat-up resumes. The cellulose and lignin structure of wood breaks down at high temperatures and boils-off much like the water did. Instead of steam, we get smoke – a cornucopia of volatile organic compounds (VOCs) and particulates. Smoke is a gaseous fuel. At 800F, the log has been reduced to its carbon skeleton, which we call charcoal. Charcoal is a solid fuel.
3. Combustion – our two fuels burn differently, each governed by The Fire Triangle. Charcoal burns as a red-hot ember (a surface oxidation). Smoke burns as an orange/yellow flame. Charcoal and smoke split the fire’s energy production roughly 50/50.

"The charcoal-only fire – charcoal is just wood that’s been taken through steps 1 and 2 at a factory. Having no volatiles, this fire is simple to control – just throttle the air supply. This allows the pit boss to load up a surplus of fuel, dial in the temperature with dampers, and get a long burn with minimal attention. The downside is that a charcoal-only fire is flavorless, making CO, CO2, and barbecue that tastes like pot roast."

***Im not buying that Volatile Organic Compounds are completely burnt out of wood in the process of turning wood to charcoal. I feel like Ive tasted them on my friends chicken all the time, but maybe that's just large soot particles! lol. And different charcoals give different flavors, so its not 100% carbon with the VOC's cooked out.

This is probably the best article I read, though it is for wood burning, not charcoal, the principals apply. Charcoal has just had the water and other compounds pre-cooked out of it so it burns cleaner and hotter. https://www.texasmonthly.com/bbq/avoiding-dirty-smoke/

"The thick smoke from a smoldering fire carries a higher concentration of those sooty solid particles. Once the fire temperature reaches 750 degrees Fahrenheit, the more flavorful compounds come forward. According to Harold McGee in his book On Food and Cooking, compounds like guaiacol and phenol provide the pungent and spicy flavors that we’d call “smoky.” Vanillin tastes like vanilla, isoeugenol like cloves, and syringol like sausage. These are the desirable flavors that smoke provides, but only at higher temperatures."

ANd from The Naked Whiz:

"But then you might ask why is bad smoke produced early in the lighting of the fire when the cooker's temperature is low? And why isn't bad smoke produced later in the cook when the fire spreads to chunks of smoking wood that haven't started burning or smoldering yet?

Let us explain. Most people start their fire by having the vents wide open which allows a small area of charcoal burn at very high temperatures. Because the burning area is small, the cooker temperature remains low. As the fire begins to spread, however, the area of very high temperature spreads and the cooker starts to heat up. When the cooker starts to heat up, you start closing down vents which limits the amount of air to the burning charcoal and reduces the temperature of the burning charcoal. Eventually, you reach an equilibrium where the charcoal is burning at a much lower temperature than when you started, and this is enough heat to keep the cooker where you want it.

So, initially, you have some very hot charcoal burning at high temperatures that produce bad smoke, but eventually the temperature of the burning charcoal lowers to a point where it produces good smoke. And this is why later in your cook when chunks of smoking wood finally begin to smoke, those chunks produce good smoke."

That explains Lower Temperatures, and for higher temperatures:

"However if the ingredients in your wood chunks burn at higher temperatures, the molecules which produce these wonderful flavors are themselves broken down into smaller molecules which are either flavorless or harsh. This is how you produce "bad" smoke. So, the difference between good and bad smoke has little to do with driving off bad chemicals and more to do with the temperature at which the fuel is burning."

 

Conclusion:

The simplistic explanation is to say VOC's need to be cooked off. This explanation works for most people, most of the time, but is technically incorrect and denies to the user a theory that bridges the gap between wood and charcoal.

There is an optimal temperature range. Too low, and the fire smoulders, creating large sooty particles, and maybe even a smattering of VOC's that haven't burned hot enough to make the flavors wanted, and instead produces something closer to creosote. Too hot, and there is a double-breakdown thing happening where the desired flavors are themselves broken down into smaller useless or nasty parts that lack what is desired.

With this "universal" explanation, 18 months into my kamado career, I think I understand enough to start using wood to smoke! and to do it properly. I have held off until now because I wanted to take things one step at a time and not develop any bad habits, which is hard to do when functionally a dummy and don't understand how things work. This wood smoking to charcoal smoking continuum has taught me its all the same, except that charcoal has had most of the flavors (VOC's) "baked out" of it. I can then use wood chunks to put those flavors back in, in the proper amounts, at the proper place in the wood to charcoal cycle, at the right temperature for the desired results.

The key is minimizing the time that charcoal and wood chunks spend outside the ideal temperature while in the Kamado with food. After that, its just preference.