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View Full Version : UDS fire diagnosis please


mrboy
07-27-2014, 12:32 PM
Take a look here... this is what's left of the last fire I burned in my UDS.

I love my UDS, but ever since I built it I have not been satisfied with the amount of smoke flavor I get (not enough smokyness)

Here it looks like many of my wood chunks have gone unburned. This was a 3 1/2 hour cook at 250.

I build the fire with lump, layering in my wood chunks and leaving a few chunks on top. Light the fire with a weed burner and bring it up to temp for about an hour to get to thin blue before I put the meat on.

Any ideas how to get a better burn?

Shagdog
07-27-2014, 12:41 PM
Your burn is perfect. If the UDS is puffing thin blue at an acceptable temperature, your burn is right where it should be. You can add more wood chunks, even sprinkle in chips if ya want, but there's nothing wrong with your UDS.

Before you had a UDS, when you smoked stuff, what did you use? And what was the smoke like? I've known a few guys who moved to a UDS and said the same thing because they were used to tasting creosote from dirty smoke. Could that have anything to do with it?

chambersuac
07-27-2014, 12:46 PM
Shagdog is right. Your UDS is burning just like it should, or you'd be getting while and or dark smoke - not blue, for sure. Adding smaller or thinner chunks of wood - or chips will allow them to burn all the way, adding smoke.

This may sound dumb, but you're not getting your wood wet, are you? Some people do that to chips, but you shouldn't on the large pieces.

also, if you are using a heat deflector, that can cut down on smokiness

mrboy
07-27-2014, 12:51 PM
No heat deflector, no wet wood.

Haden't considered wood chips will give that a try and thanks for the help.

Bludawg
07-27-2014, 12:51 PM
While I agree with Shagdog I believe your base fire mass is to small. I light about 1/3chimney(20+/- briquettes) and use that to touch off the lump & chunks by dumping it on top. I leave the lid off until the thermo goes above 200 and I have TBS before I put the lid on. Takes about 30 min to get there and that includes the chimney. I've done it that way forever.

Fwismoker
07-27-2014, 01:35 PM
Invisible smoke is a good thing. I light my baskets with a torch and with in 10-15 minutes I'm cooking and it's burning TBS or invisible....that's what you want!

You're suffering from over smoke exposure and getting desensitized. Your guests will love the smoke flavor!

SmittyJonz
07-27-2014, 01:48 PM
I don't like Lump in my UDS and I mix A lot of Chunks with my Charcoal. 20-25 Chunks per Basket fill.

http://i1326.photobucket.com/albums/u645/bobjones79/27E1AC8D-6782-4781-BAD9-BB2A96F6A1A3_zpsw9mziedj.jpg (http://s1326.photobucket.com/user/bobjones79/media/27E1AC8D-6782-4781-BAD9-BB2A96F6A1A3_zpsw9mziedj.jpg.html)

StanDaMan79
07-27-2014, 02:07 PM
My UDS basket was made by wrapping the expanded metal around a propane bottle, and it holds 20lbs. It burns center down, and the outside coals just fall to the middle. I'd say put your smoke wood in the middle so more of it burns, but like the others said, you's is burning as it should.

krshome
07-27-2014, 03:09 PM
Like Bludawg says I light a chimney of briquettes but I fill the chimney all the way. I use a paper towel rolled up and soaked in olive oil stuck in the center of the chimney to light it I find lighter fluid effects the flavor in a smoke. When the briquettes are all white with ash I then evenly spread them over my full basket. That should get everything in the basket to burn down evenly. My bet is if using a weed burner your only getting one spot burning, at lest that what the picture makes it look like. My basket has about 6-8 fist sized pieces of wood through out. I use less wood on things like ribs and chicken and I get plenty of smoke in my UDS. Give it a try.

mrboy
07-27-2014, 03:40 PM
First of all, thanks for all the help.

No doubt I'm getting smoke polluted... sometimes I can't taste much of anything until the next day.

I'm going to try more and smaller chunks, and and go back to chimney style of lighting the basket and see if that makes a difference.

I'll report back.

Fwismoker
07-27-2014, 03:46 PM
No chimney required...just light the edge of the basket with a torch.

SmittyJonz
07-27-2014, 06:18 PM
Try some Stubbs Briquetts.

bstomper
07-27-2014, 07:16 PM
I've only done 8 cooks on my UDS ,# 9 tomorrow, ribs, st louis style, so I am no expert. Since cook #1 I have used the minion method buy dumping the lump charcoal in my basket(14" diameter x 12" high) and digging a hole in the middle of the charcoal but not all the way to the bottom. then I light about 12-15 kingsford birquetts in my chimney, when they ash over I dump them into the hole in the charcoal which will fill it to the top. Then I just toss in 3 or 4 chunks of wood around the outside edge of the basket and one directly on the birquetts. I am cooking on it with TBS in less than 15 minutes with only one ball valve 3/4 open.
The last time I cooked on it I thought I would try something different so I just poured the lit birquetts ontop of the level basket of lump then tossed in some chunks of wood. I also had some wood layered through out the basket. I had to keep all 3 ball valve open to get it up to temp and it took a long time to do so, close to an hour. I never did have TBS it was more like white smoke but I cooked on it anyway. The food had too much of a smoke taste, no where near the great taste of the TBS taste. The good thing about trying something different is at least I found out which method my UDS likes.
Your UDS may burn diferently than other UDS'S because of several different factors, type of charcoal, size of basket, size of holes in your basket, how air tight your drum is........ You will have to expeirement to find out what work in your UDS and once you do it will be so enjoyable to cook on.
Having said all this, I agree with the above comments that it looks like it is burning fine, especialy if you are getting TBS. When I first started smoking I thought the more smoke coming out of the stack the better but that is not the case.
Good luck

Happy Hapgood
07-27-2014, 07:25 PM
What you have there is an oxygen starved fire. It does not have enough combustion air. It's not hot enough. Just enough to smoulder but not really for full combustion of the fuel.

Sweat'in Pig
07-27-2014, 07:36 PM
I run my UDS at a minum of 275. that seem to take care of any unburnt wood chunks. 275 target.

mrboy
07-27-2014, 08:07 PM
What you have there is an oxygen starved fire. It does not have enough combustion air. It's not hot enough. Just enough to smoulder but not really for full combustion of the fuel.

Ok, oxygen starved fire, that's along the lines of what I've been thinking. A fire is nothing more than fuel and oxygen.

I've got 3 - 1" holes, 2 with nipples and one with a ball valve.

What would you suggest? Basket is 3" of the bottom air intakes are 1" from the bottom.

krshome
07-27-2014, 08:29 PM
Ok, oxygen starved fire, that's along the lines of what I've been thinking. A fire is nothing more than fuel and oxygen.

I've got 3 - 1" holes, 2 with nipples and one with a ball valve.

What would you suggest? Basket is 3" of the bottom air intakes are 1" from the bottom.

That all sounds perfect. Look to see if the holes are clogged, all sorts of things can get in there and make nests. You should have enough air with just the ball valve opened 3/4 of the way. What size holes do you have for venting up top? What temps are you cooking at and is you thermometer for your pit accurate?

blackdog043
07-27-2014, 09:24 PM
Try burying your chunks, when you don't use a defuser. Your food is dripping on the top getting them wet and preventing the chunks from burning correctly. I might put one piece on top, then bury the rest about 2 inches. I use a weed burner to light three areas of lump.
When you take your lid off after your cook is done are the coals burning below the top layer? I would be willing to say yes they are. Thats the way mine burns without a defusser, thats why I bury mine.

mrboy
07-28-2014, 05:32 PM
I think TOAST is onto something, I think I'm burning an oxygen deprived fire. So I checked my intakes, they're 99% clear, but I cleaned 'em out anyway with some white vinegar.

Since I'm running a dome top, I decided to increase my exhaust by drilling 4 - 1" holes in the top and adding some magnets off the fridge for control if I need it.

What do you think?

Shagdog
07-28-2014, 06:42 PM
If your smoke was thin blue, your fire was not oxygen deprived. Not enough air would cause thicker white smoke for a while as your barrel temp went down to a level that the air your fire was getting could support (like if you started a bigger fire than your air flow could maintain) if you are able to maintain your desired temp with TBS, your fire is getting what it needs. In the end, if you start a fire in a UDS and leave everything alone (valve intakes, etc) eventually your drum will settle in at the temp that can be sustained given the conditions you are providing. An oxygen deprived fire in a UDS will not be that way for long. Your temp would just drop until the O2 level was correct. I wouldn't drill any more holes. I think you're over thinking it.