Question for the chefs about cook surface temps

I'm not a chef. They barely trust me to buy beer, wash dishes and maybe if I'm lucky prep chicken. (our best protein btw But I do have a few welders, I can fabricate and I know a bit about math, physics, computers and areo/hydro/thermal dynamics. (nerd)


Question is: Would you rather have a completely even temp cook surface or known hot and cold spots/areas? When I say "known" hot and cold, think about a target with rings or something exact, specific and defined --3 inches left of center will always be three degrees less than the cc thermometer reads, two inches to the right of center will always be four degrees hotter, etc. Not sometimes, ALWAYS.


Part of me says make it even and let chef sort the rest. Part of me says having hot/cold areas would let chef place things in different ways to take advantage of the hot/cold spots so when it comes time to box/turn-in, we have more to choose from...


Thoughts? I'm mid-build on a new cooker and having this discussion with them now. Wondering what others that compete think. I don't want to say what they are telling me because as someone who didn't go to culinary school, I'm curious to see the forum's response to see if popular opinion says I'm right/wrong (or they are right/wrong). Thanks!

Thanks for the replies. It's been a huge help. I appreciate it!

ynotfehc said:

Doesnt give you a definite answer

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Actually that was extremely helpful so thank you. I'm making a purpose built hot & fast drum. It's not a fancy UDS, it's a double walled, fully insulated cylinder. Inside volume will be roughly the size of a 30gal gateway. Outside dimensions will be about same height but smaller diameter than the big gateway. We will pass it around so everyone has a chance to cook on it and then if they like it I'll build four more (one for each protein).

So there will be no loading this thing up with 2 cases of brisket

Blizzard said:

I went to culinary school. I’ve never seen any cooking surface without hot and cold spots. I think they are necessary. You have to be able to move food around to reach the desired temp for that item. You know? If you are cooking steak and asparagus like pictured in the thread from “smoke ninja” you want them both done at the same time. Granted, he put the steak on first, but probably moved it to a cold spot while the asparagus was cooking.

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This is for a hot & fast drum build so "cook surface temps" is a little misleading. Sorry. And weird, the one guy fighting me who wants the temps exactly even is the cook/chef. (the only one of us that went to school to cook) I don't even own a smoker. This was supposed to be mine... For me to use in my backyard. Somehow (after beers and fireball) it turned into a prototype/experiment comp drum. We'll pass it around so everyone can cook on it then if they like it I'll build a few more (one for each meat). Which means I still don't own a smoker :doh:


I keep thinking about things like chicken and ribs. I know when you box you want everything to look pretty, even sizes, etc. but my thought was that (in some cases) by having either more to choose from, or having slightly different sized pieces but all still cooked well, that might stand out to a judge --wow, the large and small pieces of that brisket are all cooked perfectly... idk. That's where my head is at, but the guy who went to school wants something different.

IamMadMan said:

When you talk of surface temperatures could you be referring to a grill or a griddle?

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Sorry, that was my bad for not specifying. The reason why I put this in the comp section was because I assumed people would understand I was referring to a smoker. I'm making a purpose built hot & fast drum. I'm referring to "cook surface temps" because (for me) it's easier to think of the circle grate like a target or pizza pie where I can identify temps, etc. I like your home HVAC analogy. I might steal that. I've done some work with seasonal changes to drag coefficients of automobiles. (how much the drag coefficient changes when a car has snow, mud, dirt, pollen, etc. on it vs. when it was tested in ideal conditions in a wind tunnel) I'm probably going to steal your home analogy. I like it. Thanks!


This is for a hot & fast drum. Very small grates, very isolated and controlled environment, etc. When I say isolated and controlled, I'm building a double-walled, fully insulated cylinder (this is not a fancy UDS) and have been going back and forth on different methods to evenly distribute or disburse air flow --or alternatively, methods to intentionally direct or disburse air such that there will be consistently identifiable hotter or cooler parts in the cooking area of the drum. Make sense?

m-fine said:

As for the original question, the perfect cooker in my opinion would have three options: 1) perfectly even 2) a smooth gradient between two different temps, and 3) two or more hard zones that are even within each zone. Which one I want is going to depend on what I am cooking.

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Thanks. I think I'm starting to realize that. I'm part way through a smoker I'm converting from a traditional offset to a RF design and I've thought a lot about tuning plates vs. full RF so you can intentionally vary temps. But that's a little harder to do in a drum...

Regarding the thermocouples, I'm a huge car guy. I've built (breadboards, soldered my own circuits/wiring/controllers) many engine management systems. All of them have at least one K type somewhere. I haven't bought them in a while. Have you had good/bad results with any one type of brand or seller? I had a race car with a buddy for a couple years. If you think going to bbq comps is expensive try owning a race car I usually paid a premium for Siemens brand thermocouples because between the cost of getting to the track and the cost of rebuilding an engine, it wasn't worth the risk. This is a little different. I don't mind buying a 5-10 pack and keeping spares handy in the event of a failure. But I don't want to start with junk and have problems.

Thanks!

Ron_L said:

I'm a geek and I love this option, and would probably use it, but a tube of generic biscuits is pretty cheap :-D

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Hey Ron, sorry I started this thread in the wrong place. (over in the comp sub)

I get that this is a delicate balance between art and science. And there is also a very big difference between traditional low & slow and the new hot & fast mentality of the competition circuits. Maybe I'm super nerdy (I'm using parts of old server racks for this drum build.) but the cost of K type thermocouples are super cheap these days. Even good quality ones, like the kinds they use in nuclear power plants and mission critical stuff. I'm building a drum so I don't need 50,000 temp sensors across 55 gallons of cubic space. But I am going to put a few extra temp sensors here & there so I can do some data logging. I'm building a double walled insulated drum, so stupid stuff like when temps start to quickly drop in the insulated space maybe that is a sign that coals are starting to burn out, or that in 5min I'll need to turn on a blower fan. I like to look at those numbers. (that's pretty much what I do for a living)



Thanks again everyone for the feedback and replies. It's been a huge help.

mjpmap said:

In my case, I use different cookers for different needs. I learn the most from my worst mistakes. The purpose of my post however, is to compliment you for the thought you are putting into your build. There are a limited number of people who would think that detailed about a cooker. Hats off to you. Guessing you’ll have a successful build career if you want it.

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Thanks! I appreciate the compliment! Everyone brings someone different to the table. I like metal fabrication and all the other nerdy stuff (K-type thermocouple temp sensors) that goes with it. My job is to deliver chef the best tool/cooker I can so he can take over from there. After that I have no problem washing dishes and drinking lots of beer. :mrgreen: I've never thought about building professionally. I'm doing this for fun. Paying our bills involves me driving a desk and staring at monitors. We'll see. One step at a time. This thing could be out on the curb in a week.


I had a boss tell me once that it was his job to provide me with a big/wide enough safety net that I could grow. So that I could make mistakes and learn from them. When I asked him "What if I screw up really bad?" his answer was "My job is to let you screw up a little bit. If you screw up a lot, that's my fault." I try to approach my career (and soon kids/family) like that too. I firmly believe we learn more from our mistakes than our successes.


Best!

pharp said:

Looking forward to seeing the results. I would stay away from purposely putting different size/shaped pieces in your box. The judges will likely score down in appearance if they look different. Then each judge will take a piece (or pieces if they are small) and that judge will only be tasting that piece, so they wouldn't know that the small piece was cooked as well as the large piece or vice versa.

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Thanks. That makes sense. And I guess it shows how little I know about comps. Either way, thank you. I wasn't sure how they judged --whether they all saw the box as a presentation or if they just passed it around and took whatever was left. I guess that's why you need to know about the whole picture to compete, not just one part.

Roast Beast said:

Just a quick two cents . . . consider more than the grate temperature and the evenness (or not, as you prefer) of that. Consider how much air is flowing though the smoker and whether that volume of airflow is sufficient to support a clean-burning fire, or whether the insulated environment will necessitate either a smaller fire than optimal for flavor or starving a larger fire for air, such that the character and quality of smoke is less than optimal.

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Thank you for that comment. I've been thinking about that a bunch. I'm a car guy. Have had (and crashed a few) amateur/hobbyist race/track cars, etc. With a car it's easy. An engine is just an air pump, the fuel (usually gasoline) only facilitates the movement of air from the intake air filter, through the engine and out through the exhaust. Of course you want to provide an optimal A/F (air fuel) ratio so the fire gives you the best bang for your buck. But along the way you try to do as much as you can to limit air flow restrictions, size air intake and exhaust appropriately, smooth things out --or, for example, very similar to Mr. Hunsaker's smoker, we often will put swirls on the back side of valves to facilitate a swirling effect which causes better air/fuel distribution within the cylinder.


But I don't really know all that much about smokers. This is new to me.


I started out with a bunch of standard 55-gal drums (34" tall, ~22" wide), a bunch of small grill propane tanks and a couple old air compressor tanks. First thing I did was cut the tops and bottoms off of a couple drums. (there were all sealed drums) That gave me a pile of tops/bottoms and a few open/hollow cylinders. Next I cut one drum the long way down the factory welded seam. With the tops and bottoms cut off, this lets me overlap the cut edge of one drum to shrink the cylinder diameter and slide it inside another drum. This is how I will achieve the insulation part.


Have you seen the Harvard smoker? UN-rated drums (the drums with ridges we typically see in the US) are pretty cool, the crimp rings both curve in and curve out from the drum cylinder wall. This makes tapers and circumference/diameter changes much easier. (You have to cut up a bunch of drums to get the right angles and ring portions and it involves a bunch of welding --but it works.) I'm not going nearly as crazy as that Harvard smoker.


The drums I have are about 22-3/8" wide (thin metal so ID/OD doesn't matter much). The ring around my fire basket is 16" diameter (12" tall, rounded at base). So 22-3/8" minus 16" gives me 6-3/8" to play with --or 3-3/16 between the edge of my fire ring and the outside circumference of the 55gal drum. Down at the fire basket and fire ring, I'm going to insulate that with 2" of mineral wool between an inner liner and the outer drum cylinder. I'm going to carry that 2" insulated liner up roughly 20 inches. So the ID of the bottom 20" of the drum will be 18". After that I'm going to taper out the inside liner and at same time thin the insulation down to 1". So up top where cook grates go will be ~20" wide. A typical drum is ~34" tall. I'm making this drum longer (extending it) to a little over 40". Slightly larger than a small gateway but not quite as tall as the big gateway. That'll give me room for a couple rack heights, a diffuser plate and a couple other things I want to try out.


Because of the ID size change (going from 18" ID to 20" ID) I do understand that the velocity of air should slow down slightly when it goes from 18" to 20". I hope this is a good thing. Assuming the air expansion doesn't lower temps at all, the slower velocity should give the warm air more time as it passes by the meat. This will also mean more smoke --my guess is both of these issues will be insignificant.


I am planning on using a 3" diameter, 18" long chimney with a 1-1/2" diameter air intake at the center base of the drum. My fire basket will be 12" (round) by 12" tall. I don't know how much air it takes to feed a fire basket of that size. My (ignorant) guess is that 1.5" will be fine since guys set the intakes on their brand name drums pretty dialed back and they hum along for hours like that. I'm more worried about having such a large diameter chimney and it being 18" tall. Since you control fire and cc temps via air intake, I don't want a terribly long stack creating a vacuum inside the drum. Besides air leaks I'd imagine that wouldn't be the best for cooking.


Do you have any resources or advice on smoke quality and clean burning fires? Really the reason why I insulated (correction, it's not fully built yet, the reason why I am insulating) the drum is more with the mindset of conserving fuel. So that the cooker can either burn longer or needs less fuel to operate. Also ideally better temp control. I guess we'll have to figure it out. Perhaps because it needs less fuel a hot & fast cook may not provide enough smoke. Or we will need to learn how to use this fire basket because it may be different from other cookers.


I would tend to think that if we regulate the amount of fuel we use, the fire shouldn't ever be starved. idk. Trial and error. This thing might end up on the curb for the scrappers next week. Who knows.