HomeRoast Digest


Topic: Using A Thermocouple With An HWP? (4 msgs / 111 lines)
1) From: JB Christy
Okay, so I have a thermocouple and I have an HWP.  How do I use the former with
the latter?  I've stuck the thermocouple wire down through one of the holes in
the lid after loading with beans and assembling the roasting chamber.  However,
the thermocouple is so sensitive that any movement of the probe gives me a
wildly different temperature reading (varies by as much as 30F).  If I try to
keep the tip in contact with the tumbling beans, the temperature never settles
down to a stable reading.  If I keep it far enough away that the beans don't
bang it around, then it never reads hotter than ~300F.
Ideally, I'd like to find a way to attach the probe semi-permanently so I'm sure
I'm measuring the same thing across batches.  However, the easiest/most obvious
way to insert the probe is through the holes in the lid, but I have to take the
lid off for every batch to add/remove beans.
Has anyone here already come up with a clever solution, or do I have to actually
think for myself?  [I hate it when that happens! ;-)]
BTW, the woven fiber insulation/covering of the thermocouple wire frayed
dramatically the very first time I tried to use it.  Can anyone recommend an
appropriate adhesive to keep the fabric from fraying while still enabling the
wire to slide through the holes in the lid?
a T d H v A a N n K c S e.
--JB
homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast

2) From: Dan Bollinger
<Snip>
with
<Snip>
JB,  I've been using the 'through the lid' method, too.  My thermocouple has
a yellow teflon coating so it doesn't fray.  I drilled one of the breather
holes larger to accept it, but like you say, it wanders about.
I am going to drill a small hole in the bottom of the metal funnel and mount
it permanently.  I may have to file a slot for the wire to 'fish' through
when putting the chamber on the base.  I'll let you know what I figure out.
dan
homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast

3) From: Jack Berry
Same here JB & Dan.
I enlarged one hole a bit to accept the thermocouple but it wanders. Like
you JB, I see huge differences in temperature when the probe moves much. I
think the best location would be about half the radius from center. I was
thinking of adding a stiffener (maybe stainless wire). The thermocouple wire
would easily lace around the stiffener. Problem then becomes; "how to brace
the stiffener?"
BTW, the insulation on the thermocouple is pretty much non-essential in this
application. Don't worry if the insulation near the end comes off, as long
as it doesn't wind up in your grinder!

4) From: Dan Bollinger
Sivetz says that the thermocouple should be as far away from the 'spout' as
possible, but buried in a pile of beans.  Obviously, you don't want it too
near the sides.  I'm going to mount mine about two-thirds the the radius
from the center.   Dan


HomeRoast Digest