HomeRoast Digest


Topic: More affordable fluid bed roaster control? (3 msgs / 137 lines)
1) From: Mike McGinness
The more I use my Rostos with separate throttle control for heat and fan the
more I'm thinking an expensive variac may not be necessary for many. I did
another 1/3# batch this morning, ambient 32f, max voltage I use used to
heater was 118v. I'm using the fan more for temp' ramp control from around
380f up. As the beans loose moisture less fan speed is needed or wanted to
maintain movement. Reducing fan speed results in corresponding increase in
temperature. My final fan voltage for the Sulawesi roasted to 450f just
before 2nd crack was 95v, all the while maintaining excellent bean movement,
(Rockin' Rosto a thing of the past:-), heater voltage had been left constant
at 118v since 400f point of ramp. Though using a variac to control the
heater offers the most potential control enabling very fast and slow
roasting, using a heater controller to vary heater voltage from line in down
(like Chris Beck used, except controlling just the heater in this
application) may be more affordable. New 10A+ variacs run $100 or more. I
got "lucky" and have my used 10A variac on the way for $35 inc. s/h (eBay).
I'll check out what's out there to use for a "heater trimmer". Of course, if
your line voltage varies a lot or you have low voltage this would not be a
good option, variac still the way to go.
MM;-) aka Kona Konnaisseur miKe mcKoffee
Dual Variable Transformer Rosto Roasting
Rocky grindin' - Miss Silvia brewin'
homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast

2) From: Lowe, David
I would be interested in what you find. 
I'm still using a WB popper at the moment, wired to cut out the primary =
element for a "cooling cycle." I have been roasting outside and using =
the a combination of a cardboard box with a couple of boards on top to =
keep the temperature up. I put a dial thermometer in the box (it only =
goes up to about 200 or 300 F) to measure the ambient temperature in the =
box and move the boards to keep it at 70 - 80 F. Since I live in Western =
Washington that works well enough for the temperatures that I encounter, =
even early in the AM. 
But, I am thinking of purchasing a roaster. It sounds to me like you are =
able to roast more than the 4 oz. that the Rosto is suppose to be =
capable of. Is that a matter of higher voltage to the fan? If I'm going =
to purchase something I would like it to be able to roast 1/3 or 1/2 lb. =
at a time, but still be able to do smaller quantities when appropriate.
Dave Lowe

3) From: Mike McGinness
From: "Lowe, David" 
But, I am thinking of purchasing a roaster. It sounds to me like you
are able to roast more than the 4 oz. that the Rosto is suppose to be
capable of. Is that a matter of higher voltage to the fan? If I'm going to
purchase something I would like it to be able to roast 1/3 or 1/2 lb. at a
time, but still be able to do smaller quantities when appropriate.
My two Rostos are behave somewhat differently. My two year old always needed
a bit of rocking for 1/3# batches, 1/4# early greens movement fine. The
second Rosto, 'bout a year old now, moves 1/3# early greens no problem. This
is for 120v.
Boosting fan voltage to about 140v the old Rosto does 1/3# no rockin', the
newer one 1/2# no rockin' for early bean movement. Doing 1/2# batches does
require more early heater voltage to maintain a given profile. But still no
sweat doing a roast never exceeding 120v to heater. However, if I'm slightly
behind on my ramp, it's great to be able to give the heater 125v or so for 5
or 10 sec. then back off. That does require a variac to the heater. If you
worked at it you can get a 10A variac for under $40 including s/h. Took me
four auctions but finally got one for $35 inc. s/h (eBay). The fan control
circuit is relatively inexpensive. Currently I can get all the parts except
mounting box for under $10! (while the $3 surplus 25.v 2A transformers last,
then add $7 for Radio Shack price of $10) Cheapo 600w light dimmer ($4)
works fine, dual plug socket about fifty cents. But the transformer, dimmer,
and plug wired together really should be put in something! I used a 4-gang
box for my prototype, $10 Home Depot, plus a couple bucks for the three
plate covers. (covered the xformer since taking the pics)
BTW, this same setup would work fine to control a popcorn popper roaster.
MM;-) aka Kona Konnaisseur miKe mcKoffee
Dual Variable Transformer Rosto Roasting
Rocky grindin' - Miss Silvia brewin'
homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast


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