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Effects of high-flow aftermarket fire grates

I had previously seen some posters who suspected that aftermarket high-flow fire grates may be responsible for more than a few cracked bases. 

While I attempt to make no such claims here, I did want to share an observation I have made with respect to the heat emanating from the bottom of my Mini Max while having a KIck Ash Basket in place. 

Tonight, I roasted some veggies before searing a ribeye at 550. Everything was delicious.

When I went to move my Egg back to its home after cooking, I was surprised to see significant singe marks in the cedar table the Egg had been placed on for the cook (photo below). After more than a year of cooking on this table with the stock fire grate with no ill-effects, I think it's safe to conclude that the KAB is responsible (and in a single cook). I suspect that the small pieces of charcoal that fall through the grate during the cook ultimately end up resting on the inside of the cooker's base, throwing a great deal of heat below the Egg. 

Just thought that others may benefit from being made aware of this phenomenon.

The steak photos are purely gratuitous.  










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Comments

  • Do you always sit it on the same spot?

    Little Rock, AR

  • GrateEggspectations
    GrateEggspectations Posts: 9,182
    edited August 2017
    Exact same spot. The table is barely wider than the Egg, so there are absolutely no variables in this regard. The burn cannot be the result of repeated uses. It went from unblemished to singed in one cook. 
  • HeavyG
    HeavyG Posts: 10,323
    Interesting scorch pattern.
    “Reality is that which, when you stop believing in it, doesn't go away.” ― Philip K. Diçk




  • Skiddymarker
    Skiddymarker Posts: 8,522
    edited August 2017
    Interesting observation, do you have a dual probe thermo? Reason I ask, occasionally when using only the pit probe of my Mav 733, I've "parked" the food probe under my table nested MBGE. I;ve never seen it read over 125ºC. Maybe you could try the same  cook with and without the KAB and see if there is a measurable difference in temps under the grill. 

    BTW - nice looking steak there....
    Delta B.C. - Whiskey and steak, because no good story ever started with someone having a salad!
  • Mattman3969
    Mattman3969 Posts: 10,457
    How hot was your fire?

    -----------------------------------------

    analyze adapt overcome

    2008 -Large BGE. 2013- Small BGE and 2015 - Mini. Henderson, Ky.
  • GrillSgt
    GrillSgt Posts: 2,507
    So you removed your grate before adding the KAB?  I didn't realize I was supposed to. 
  • In use a KAB, but still use the grate. I do not think the grate should be removed just because you are using a KAB. 
  • Ozzie_Isaac
    Ozzie_Isaac Posts: 18,943
    In my MM and medium, I remove the grate.  Main selling point for me is increased airflow.  KAB is recommended to be used without the grate in all Eggs.  Even the XL with the new thicker gauge wire.
    A bison’s level of aggressiveness, both physical and passive, is legendary. - NPS
  • In use a KAB, but still use the grate. I do not think the grate should be removed just because you are using a KAB. 
  • Exact same spot. The table is barely wider than the Egg, so there are absolutely no variables in this regard. The burn cannot be the result of repeated uses. It went from unblemished to singed in one cook. 
    Perhaps the constant heat over a period of time had that effect?  Not necessarily the single cook. You can burn paper eventually with a magnifying glass. 

    Little Rock, AR

  • RRP
    RRP Posts: 25,880
    Another vote for removing the grate when switching to a KAB. The wide open air flow allowed by the design of the KAB is why I went that route! I mean...why hamper the air flow? 
    Re-gasketing America one yard at a time.
  • RRP said:
    Another vote for removing the grate when switching to a KAB. The wide open air flow allowed by the design of the KAB is why I went that route! I mean...why hamper the air flow? 
    Have you found with the grate removed a harder time keeping a low and slow?  Just curious. 
  • Ozzie_Isaac
    Ozzie_Isaac Posts: 18,943
    ninnymugs said:
    RRP said:
    Another vote for removing the grate when switching to a KAB. The wide open air flow allowed by the design of the KAB is why I went that route! I mean...why hamper the air flow? 
    Have you found with the grate removed a harder time keeping a low and slow?  Just curious. 
    No problems here.  Actually the opposite.  L&S on MM was a bit shaky before KAB for me.  With the KAB it has never snuffed out.
    A bison’s level of aggressiveness, both physical and passive, is legendary. - NPS
  • jtcBoynton
    jtcBoynton Posts: 2,814
    Any idea why the folks at BGE use a ceramic fire box, ceramic fire ring, and ceramic fire grate (originally)?  It would have been less expensive to make an egg without using ceramic for these.  Maybe they help protect the base from the intense heat of the fire?
    Southeast Florida - LBGE
    In cooking, often we implement steps for which we have no explanations other than ‘that’s what everybody else does’ or ‘that’s what I have been told.’  Dare to think for yourself.
     
  • RRP
    RRP Posts: 25,880
    ninnymugs said:
    RRP said:
    Another vote for removing the grate when switching to a KAB. The wide open air flow allowed by the design of the KAB is why I went that route! I mean...why hamper the air flow? 
    Have you found with the grate removed a harder time keeping a low and slow?  Just curious. 
    No. Temperature control is a matter of the bottom vent, not the grate or KAB.
    Re-gasketing America one yard at a time.
  • How hot was your fire?
    Dome thermo got to 550 and no higher. 
  • CanDid
    CanDid Posts: 106
    It's not just that small pieces of charcoal fell thru the KAB and onto the ceramic. This happens with the cast iron grate. But what probably happened was the actual amount of hot coals that falls thru the KAB is far greater than the cast iron grate and that is what caused the bottom of the ceramic to get much hotter than before.

    The KAB should be used with some trepidation. I know a lot of Eggers on here use it full-time without the cast iron grate, but personally I only do that with a firebox full of smaller lump (ie. towards the bottom of the bag, cheaper lump). A firebox full of small lump is packed together more tightly and tends to struggle for oxygen a little more on the cast fire grate than the bigger lump does. The medium and larger lump will burn hotter, faster and I set the KAB on top of the cast iron grate for that, which is most of the time.

    I'm sure I'll get some criticism about this, but to each his own. Just remember, there is a reason BGE states that "using any parts inside the EGG other than authentic BGE components" voids the warranty.
    BGE XL
    NWArkansas
  • HeavyG
    HeavyG Posts: 10,323
    CanDid said:
    ...

    I'm sure I'll get some criticism about this, but to each his own. Just remember, there is a reason BGE states that "using any parts inside the EGG other than authentic BGE components" voids the warranty.
    And that reason is more likely an escape clause to give them an out for avoiding warranty claims should they so desire.

    I'm guessing that clause even pre-dates the existence of the Kick Ash Basket.
    “Reality is that which, when you stop believing in it, doesn't go away.” ― Philip K. Diçk




  • stlcharcoal
    stlcharcoal Posts: 4,684
    edited August 2017
    HeavyG said:
    CanDid said:
    ...

    I'm sure I'll get some criticism about this, but to each his own. Just remember, there is a reason BGE states that "using any parts inside the EGG other than authentic BGE components" voids the warranty.
    And that reason is more likely an escape clause to give them an out for avoiding warranty claims should they so desire.

    I'm guessing that clause even pre-dates the existence of the Kick Ash Basket.

    I have an old owner's manual from 2008 here......different wording, but says a similar thing.  I'll be over at my parents' house later today--will see if their mid-90's manual says that.

    On the subject of warranties, I had one of my dealers tell me their rep from a bouy shaped grill company said that their warranty is going to prohibit the use of lump charcoal--unless you use their branded briquettes, the warranty is null/void.  There no way for them to enforce or monitor it, but maybe it helps with their insurance?  I doubt the dealers in the middle will put up with that crap.
  • ronw9471
    ronw9471 Posts: 112
    I use the original cast iron grate with the KAB atop that. I figured that the KAB alone would allow too many burning coals to rest atop the bare ceramic bottom. 
    Parrish, FL

    My Photo Website: www.ronwooldridgephotography.com

    XL Big Green Egg
  • Yno
    Yno Posts: 529
    The entire design of the Egg is built around 'restricting air flow). Unless you are doing very high temp cooks or clean burns, I would think that the air flow is restricted by the vents regardless of the LAB or the grate. Would not a cook at X degrees have the same air flow independent of the means of controlling it?
    XL BGE in San Jose, CA. Also a Pit Barrel Cooker, a Cal Flame P4 gasser, and lots of toys including the first ever Flame Boss 300 in the wild. And a new Flame Boss 500.
  • HeavyG
    HeavyG Posts: 10,323
    I use my KAB sans original grate. I just don't buy the notion that little embers have enough energy to harm the ceramic base (which is likely kiln fired at over 2000°F).
    “Reality is that which, when you stop believing in it, doesn't go away.” ― Philip K. Diçk




  • How much difference is there between the bottom of the kick ash and a hi-que?  I have hi-ques in my eggs. Just seems to work better than the stock for me. Ive had a couple overnighters try to snuff with the stock but never with a hi-que. 

    Little Rock, AR

  • If it is true that more bases crack when using the KAB versus the original fire grate, my guess is that is has very little to do with some embers dropping through. It is probably more to do with heat radiating down from the fire. The original grate has air holes that make up what, 20% of the entire grate? Much more heat heading south with a KAB. It would be very easy to test all this. Take a temp reading under the egg at X degrees using an original grate, and also with the KAB. Also take readings of both with the embers cleaned out from the bottom. Personally, I am not worried about it. No cracked bases here yet, and if it happens I will change them out. Without the original I have never had an airflow problem, with it I have had a few.
  • CanDid
    CanDid Posts: 106
    HeavyG said:
    I use my KAB sans original grate. I just don't buy the notion that little embers have enough energy to harm the ceramic base (which is likely kiln fired at over 2000°F).
    I'm not trying to say you're totally wrong with that statement, but just read @YukonRon experience in his post above. Others have had similar experiences.

    What is the application for the firebox? Is it to assist in air flow? Is it to prevent the base from becoming too hot to touch? Is it to protect the base from cracking? Why not have a fire grate that holds the charcoal next to the base instead of the added cost of a firebox?

    Remember, the firebox has a slit in it so that it can expand and contract without cracking. The base does not.
    BGE XL
    NWArkansas
  • RRP
    RRP Posts: 25,880
    CanDid said:


    Remember, the firebox has a slit in it so that it can expand and contract without cracking. The base does not.
    Help me understand how a ceramic fire box expands when heated.
    Re-gasketing America one yard at a time.
  • Botch
    Botch Posts: 15,429
    @Yno: you are correct; I actually did the math a year or two ago and posted the figures here, the bottom vent (even wide open) is smaller in area than the holes in the original grate.  
    @SemolinaPilchard : you are correct, the metal plate would block radiant heat from above, which the Hi-Q and KAB would not; I hadn't thought of that before.  And actually measuring the bottom temp, w and w/o the OEM plate, is easy enough to do to be sure.  
     

     
     
     
     
    _____________

    "I mean, I don't just kill guys, I'm notorious for doing in houseplants."  - Maggie, Northern Exposure


  • HeavyG
    HeavyG Posts: 10,323
    Methinks the impact (if any) of radiant heat from a KAB (or other grate) would rapidly diminish once even a thin layer of ash settles onto the base.
    “Reality is that which, when you stop believing in it, doesn't go away.” ― Philip K. Diçk




  • CanDid
    CanDid Posts: 106
    RRP said:
    CanDid said:


    Remember, the firebox has a slit in it so that it can expand and contract without cracking. The base does not.
    Help me understand how a ceramic fire box expands when heated.
    I can't tell if you're being serious or not, but it's called thermal expansion. Look it up. You can start on the BGE website where they state, "This cut allows for repeated heat expansion and contraction without putting stress on the ceramics."
    BGE XL
    NWArkansas