HomeRoast Digest


Topic: Hottop B profile (6 msgs / 203 lines)
1) From: Cameron Forde
I'm really enjoying roasting with the HT-B.  I set the % power
(increments of 10%) to the heater and the % fan speed (increments of
25%) and depending on the amount of beans and the characteristics of
the bean, the bean temperature changes at some fixed rate.  What I've
found so far is that for 300 g of beans at full heater power I'll see
a 20F/min temp ramp with the fan off.  If I turn the fan on to 25% the
ramp slows to 15F/min and at 50% fan the ramp is about 11 F/min.  This
is very likely sensitive to ambient temperature, but I'm roasting
indoors at 21C.
With this knowledge of how to control the ramp I'm now adjusting my
profile accordingly.  I now leave the fan off for the first 3 min for
a 20F/min ramp.  The fan is then turned up to 25% to slow the ramp to
15F/min until the ten minute mark.  The fan is turned up to 50% and
then 75% (at 12:30) to slow the approach to first crack at 14 min into
the roast (fan then to 100%).  I combine this with decreasing the
power to the heater starting at the 12 min mark and dropping about 10%
heater power every minute or two (still working on this).
I've just finished roasting up some Colombia "13353" to full city (3.5
min after start of first, just before second crack would start).  The
beans smell and taste great.
Any suggestions for improvements?
Cameron
-- 
ceforde
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2) From: Brian Kamnetz
On Sat, Mar 8, 2008 at 4:40 PM, Cameron Forde  wrote:
<Snip>
Jeffrey Pawlan has developed software and modifications to control a
Hottop. People who are interested in the Hottop roaster but are
unfamiliar with Jeffrey's work may enjoy searching the list archiveshttp://www.themeyers.org/HomeRoast/on this topic.
Brian
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3) From: Michael Wade
The CCR, (Computer Controlled Roaster) as Jeffrey's extensively modified 
Hottops have become known, is a completely different animal from any of the 
standard model Hottops other than being based on the same roaster hardware. 
I'm pretty sure you would be better off  searching the archives for 
something specific to your model, but if you're up for making up something 
from scratch based on a generic profile type...
A base profile that I use as a starting place for C+, broken down to it's 
generic outline is:
Preheat machine to 420
225F in 2:30 (62.8F/min)
265F in 1:30 (26.7F/min)
295F in 1:30 (20.0F/min)
385F in 5:00 (18.0F/min)
400F in 1:00 (15.0F/min)
435F in 4:24  (8.0F/min)
As you can see this is just a generic gradually reducing temperature rise 
profile after a pretty generous drying phase.  The fifth stage is mostly 
just there to slow the roast down for the start of 1st.  There's nothing 
fancy or tricky about it and I use it a lot.
I have no idea how close the B model interface will let you duplicate it, 
and my CCR is hot rodded a little with a slightly more powerful heater, but 
the basic machines are the same and potentially should produce similar 
roasts.
Make more smoke,
Michael

4) From: Cameron Forde
Hi Michael,
Thanks for passing along your generic profile.  It looks like you have
a little more heater power than I do and that you use it to get a much
sharper initial ramp.  I don't think that I can get to first crack in
under 13 min with 300 g of beans, but I'll try leaving the fan off a
minute or two longer at the start and see if that makes better coffee.
I'm interested in hearing more about this more powerful heater you
mentioned.  What can you tell us about it?
Cameron
On Sat, Mar 8, 2008 at 11:17 PM, Michael Wade  wrote:
<Snip>
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5) From: Michael Wade
Cameron,
Probably because he bought a quantity of the machines, Jeffrey was able to 
persuade Hottop to make up a few slightly more powerful heating elements. 
My understanding is that they were not happy to do it and almost certainly 
won't ever do it again.  I don't think he has any left, so it's a moot point 
now.
I don't notice much difference in the performance of the machine with the 
larger element.  I haven't measured carefully, but the machine would produce 
a sustained temperature rise of 25 to (maybe) 27F/min with the stock 
element, and will do somewhere around 30 now with a 225g batch.
The initial ramp rate is only possible because of the preheat stored up in 
the chassis and drum of the machine.  The profile generating program 
calculates that as an average rate, but you are dumping cold beans into a 
hot drum, so they soak up a huge amount of heat in the first few seconds, 
pulling the drum down to around 150F and then gradually heating back up. 
Your machine probably does something pretty close if you calculate it.
Also, while I do 300g batches occasionally, I mostly purchase new coffees in 
2 lb quantites which gives me (5) 180g batches to experiment with.   If the 
batches are much smaller the beans may not cover the thermocouple probe 
sufficiently for accurate operation as designed.  Also that batch size fits 
in a pint jar...(smile)  Mary and I don't drink a lot of coffee, but I like 
to have several to choose from for our morning cups.
Speaking of whom, I hear her stirring.  Let's see now, Sunday morning, 
There's Mexican organic Nayarit Rustico, Brazil Daterra Farms Yellow 
Bourbon, Ethiopian FTO Yirga Cheffe Konga, Sulawesi Toarco Jaya and an old 
favorite, Idido Misty Valley.   Decisions, decisions...
Enjoy your day,
Michael

6) From: Cameron Forde
Hi Michael,
Thanks for letting us know about the heating elements.  My original
heating element was warping over time and rubbing on the drum and so I
replaced it when I upgraded.  The original lasted for nearly 600
roasts and so I don't see this as a defect.
The HT-B doesn't seem to have any way to adjust the preheat temp.  It
asks for beans at 166F.  Looking back at my notes, you are right about
the temp ramp for the original heater without fan: I'm getting 25F/min
initially (it slows as it approaches 400F).
I roasted up some Monkey this morning leaving the fan off for the
first eight min before reducing the ramp by turning up the fan.  I
think that this worked well but I need to play around with this
transition so that I can get a little bit more time between start of
first and start of second as it was 3 min this roast.  I'm starting to
think that controlling this transition is one of the keys to a good
roast.
I've been drinking americanos and a cappuccino made with Monkey that I
roasted last weekend.  The flavors are definitely crisper with the
HT-B than with the original.  This afternoon I'll brew up a FP of the
Colombian 13353 that I roasted yesterday.
Thanks again for the information,
Cameron
On Sun, Mar 9, 2008 at 8:51 AM, Michael Wade  wrote:
<Snip>
-- 
ceforde
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