[Homeroast] Air circulation inside grill roaster?

John Nordling john.nordling at gmail.com
Mon May 18 15:15:03 CDT 2015


I have to go considerably higher than RK recommends (I target 560 on T2 for
2.5 lb green in a 4 lb drum) - on two of my three thermometers.  I think
his guide temperature is set based on a thermometer through the front lid
(i.e. replacing the one that comes with your grill).

I have two thermocouples in mine, as well as an RK supplied analog dial on
the lid.  The lid one is where you expect.  T1 is slightly left of center,
and near the bottom of the drum. T2 is slightly right of center, and
approximately at the middle (all values estimated, because they're just a
couple thermocouple wires hanging in space).  The differences between T1
and T2 are typically 30-50 F, and bounce around quite a bit, about  3
seconds after a breeze passes through.  (I do have most of the venting on
the grill blocked with sheet steel, but not all).

As the thermocouples get goobered up (technical term) with coffee residue,
they bounce less.  I am planning to put a sheath on them and anchor them
better to the back of the grill shell, but haven't gotten around to it.  I
figure the sheath and the anchor will make them less bouncy, in both the
physical and the temperature sense, since they'll be better anchored, and
have a little more thermal mass.

-John

On Mon, May 18, 2015 at 2:42 PM Steve Jacobs <steve.jacobs at gmail.com> wrote:

> I'm working on a grill-based roaster and plan on adding a fan-driven
> circulation loop with a cool-air intake valve so I can rapidly adjust
> temperature if needed. I'd like to keep it a closed loop as much as
> possible to keep efficiency high and will probably use an Arduino as the
> overall controller. Gas flow will be adjusted by hand  and the stirring
> fan/air inlet should control temperature profile as long as my initial gas
> flow settings are sane.
>
> Steve
>
> On Mon, May 18, 2015 at 8:53 AM, Will Stevens <wstevens at kcu.edu> wrote:
>
> >
> > Hey folks,
> >
> > I'm curious if any of you grill roasters have considered or worried about
> > the evenness of temperature inside your roaster. I recently purchased a
> > thermocouple with a quick response time and was surprised to see that,
> when
> > moved to different points in the grill, the temperature would vary more
> > than a hundred degrees!
> >
> > My roast times/temps have never lined up with the table from rkdrums.com
> .
> > I am wondering if I'm not getting an accurate reading on the
> thermocouple.
> >
> > If any of you have any recommendations for making the temperature more
> > even in my grill (e.g. Insulation and/or air circulation ) or
> thermocouple
> > placement for better roast temp measurement, I would appreciate it.
> >
> > Will
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