UDS grate spacing question

Discussion in 'UDS Builds' started by shootmeink, Apr 21, 2014.

  1. I'm currently in the process of building my first UDS and i'm at the stage of deciding the height of the grates. So far I have 1" clearance under the ash pan which is 1 1/2" under the charcoal basket. With that setup, I end up with 32" from the top of the barrel to the bottom of the basket. I really want to have 2 grates to be able to cook a lot of ribs but I've read on this forum that I cannot go below 24" between the bottom of the basket and the lowest grate. If I follow this rule I end up with only 8" to the top of the barrel to put 2 grates. With that in mind, I was wondering what you guys would recommend for grate heights. Is it a profanity to have less than 24"? I was planning to had a diffuser plate as well.

    Thanks in advance!
    Last edited: Apr 21, 2014
  2. chiefusn

    chiefusn Smoke Blower

    If you are using a flat lid, most designs I have seen have the top rack 7" from the top of the drum and the second rack about 4" below that. Don't get to hung up on the distance between the racks and the basket. If you plan on using a dome lid, you can have your top rack at the top of the drum. Just out of curiosity, why do you have space under the ash pan?

  3. I've seen this setup on mutliple occasions where people would have legs under the ash pan. I tought it would look nicer as well. 

    I was considering having the top rack 6 inches below the top of the drum and the lowest one, 4 inches below the top one. I've also seen somewhere that with a diffuser plate and a water bowl you can reduce the 24" rule. Is that true??
  4. chiefusn

    chiefusn Smoke Blower

    The legs on the ash can really aren't necessary unless your intakes are to high. Rule of "UDS" thumb is your intakes should be lower than the basket. Most have 2" legs on the baskets with intakes at about 1-1/2" from the bottom of the drum. As long as you fall into that category, no legs on the ash pan required. That's what's neat about UDS's though. You can build them the way you want. As long as it can maintain whatever temp you like cooking at and turn out great tasting food, that's all that matters.

    As far as the use of a diffuser, water pan, or nothing, that's personal preference. Some use them, some don't. That's one of those Chevy vs. Ford vs. Toyota conversations. Are they required? Depends on who you ask.

    Some folks like the water pan cause they say it adds moisture, some say it doesn't add moisture but helps maintain a constant temp, some say it doesn't do anything.

    Some like diffusers because they help add a turbulence to the heat rising off the basket and helps to get a more even temp throughout the drum. Some will drill holes, some don't. Holes will allow fat and juices to drip on the coals and add more flavor. Diffusers without holes, just catch the juices and fat and let them boil away.

    No diffuser or water pan allows a more direct heat to the bottom of the meat and allows all the juices and fat drippings to get to the coals. Some will say that this helps with faster cooks and creating bark on the meat. Also that it adds more flavor.

    My point is, everyone is different. It all depends on what works for you. I personally use an old ECB food grate covered with alluminum foil as a diffuser on short, 6 hr or less cooks. No holes. I usually set it about 1-2" above the basket. For longer smokes, I'll use a water pan. It's what I have been successful with so that's how I UDS. My top rack is approx 18" from the top of my basket. This is about 1" down from the top of the drum casue I'm using a dome lid. My basket is 12" deep and about 14" dia. It can hold 30+ lbs of Stubbs Hardwood Briquettes and whatever wood chunks or chips I choose. Longest I have gone is 16 hrs and still have half a basket of coals left.

    Hope this helps.

  5. Wow! That is some neat reply. After reading it I decided I will cut the legs on the ash pan. I'll Lso go with the diffuser plate and a water bowl to start. 

    I sincerely thank you for taking the time to answer my questions, altough I know I got commin ;)
  6. chiefusn

    chiefusn Smoke Blower

    No problem at all. That's what joining these forums is all about. Asking and answering quesions.

  7. motown-n00b

    motown-n00b Fire Starter

    Love to hear your results. I too read about the 24" rule and designed my build around that. I have a standard size 55 gal drum. The charcoal basket I built has 3" legs with the ashpan attached right on the end of the legs. So, the ashpan basically sits on the bottom of the drum and the bottom of the basket is 3" off the bottom. My top rack is 1" below the top lip and the second rack is 7" below that. This puts my bottom rack almost exactly 24" from the bottom of my charcoal basket. I have never used a diffuser or water pan. I am admittedly new to smoking meat but I have 8-10 pork butts, 1 brisket, 4 chuck roasts, one 13 lb turkey, and over 50 lbs of chicken under my belt. Never have I had issues where I thought a diffuser or water pan would help. Sure the lower grate is a bit hotter but not a ton. For long smokes I rotate once if I have meat on both racks. Just my $0.02.

    Here's my build thread for reference


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