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Topic: Digirosto & roast times (11 msgs / 420 lines)
1) From: Paul Jolly
Jeremy (first) responded to Eddie's inquiry (second):
   
  Just giving some starting numbers for a creating a profile.... certainly
would (and have) roast at longer duration.
---In all sincerity, given ALL OF THE VARIABLES, would 17 minutes be
considered
the upper limit? Regardless of type of roast and bean?
   
  I agree with Jeremy.  While I sense a flat taste which Les mentioned in longer roasts (beyond 20 minutes, mostly), I know that using the RK drum takes longer than that yet produces excellent roasts.  I was worried at first, then realized that the first 5 minutes or more are probably devoted to bringing the beans up to initial roasting temperature (+/-220F).  Again, the old adage: if it tastes good in the cup, you're doing something right.  VERY right!
   
  However, if you want to see just how good it can get, you'll have to roast several batches, pay attention to quantities/temps/times, and compare them.  
   
  Also, Tom did a brief review of the early Digirosto a while back:
 http://www.sweetmarias.com/prod.cafferostoPRO1500.shtml   
  Cheers,
  Paul
---------------------------------
Don't pick lemons.
See all the new 2007 cars at Yahoo! Autos.

2) From: Coffeenut
This is a multi-part message in MIME format.
Longer than 20 minutes in a RK Drum?  Just curious what the batch size,
roast level and temp settings were for a 20+ minute roast in a
grill-roaster?  I do 1.5lb roasts in my grill-roaster that typically fall in
the 13min range to 1st C and 16mins to 2nd. 
Rick  
From: homeroast-admin
[mailto:homeroast-admin] On Behalf Of Paul Jolly
Sent: Monday, January 22, 2007 1:34 PM
To: homeroast
Subject: +Re: Digirosto & roast times
I agree with Jeremy.  While I sense a flat taste which Les mentioned in
longer roasts (beyond 20 minutes, mostly), I know that using the RK drum
takes longer than that yet produces excellent roasts.  I was worried at
first, then realized that the first 5 minutes or more are probably devoted
to bringing the beans up to initial roasting temperature (+/-220F).  Again,
the old adage: if it tastes good in the cup, you're doing something right.
VERY right!
Cheers,
Paul

3) From: Justin Marquez
On 1/22/07, Coffeenut  wrote:
<Snip>
Do you preheat the drum as well as the grill or just the grill?
I only preheat the grill (to 450+ F) and load 1.5 # greens in the
ambient temp drum, stick it in the BBQ grill and fire hard until the
thermocouple reads about 400 F, then I start my timer.  I try to hold
the air temp in the grill (by the T/C) at around 500 F.  There is a
regular thermometer I added in with a slim 1/8" or less probe. When
the air temps average just under 500 F, that thermometer shows 475-480
F.  Under this scenario, first crack starts for most beans in about 14
min, +/- a minute. First crack is completed in 2-3 minutes. So we are
at about 15 to 17 minutes at end-of-first (depends on the beans and
how hard the wind is blowing, trying to get the grill too cool and
requiring constant adjustment). Most beans I will either oull then
right then or in some cases will cut the heat back to about 450 F on
the thermometer to coast between first and second for a minute or so.
Then, if any 2nd cracks are targeted, I will kick it back up again to
about 480 on the themometer until 2nd's happen. (This is usually
almost immediate.) Thus I get a 1.5# roast to verge of 2nd crack in
about 17-19 minutes. (This does not count the 1 to 1.5 minutes
required to get the temp back up to 400 after loading in the cooler
drum.)
Safe Journeys and Sweet Music
Justin Marquez (CYPRESS, TX)

4) From: bruce bolden
Max batch size is 3lb  here is a link I foundgranted, I only paid 1100.00 on ebay for it.">http://www.greenbeanery.ca/bean/catalog/product_info.php?cPath"_207&products_idh1&osCside980b1e120c67d7071ae6cae383f2fgranted, I only paid 1100.00 on ebay for it.
Coffeenut wrote:
<Snip>

5) From: Coffeenut
Justin,
I do not preheat the drum, but do have the grill preheated as you do.
Temperature can be a relative thing depending upon where you measure it and
what you use for measurement.  I'm using a TelTru 5" stem thermometer that
is very sensitive to change and is measuring air temp inside the grill
(horizontally) about mid level with the drum and within about 3" of the
drum.  The TelTru is way better than standard thermometers that come with
grills and really helps with coffee roasting since you can easily see the
slightest change in temp and make an adjustment if necessary.  I have a
double layer of those ceramic diamond shaped briquettes above the burners,
so no flame is coming in contact with the drum.  I also have the drum
lowered so that it is about 1" above those ceramic briquettes.
Understanding what and where I'm measuring the temp, I preheat my grill to
about 650F, open the lid, mount the drum and hit the switch to start the
motor.  I start timing from the moment that I start the motor.  The grill
temp will fall off to around 450F and slowly rise back up into the 600F
range.  At that point, I back off the gas (from Full on) to a slightly
lesser amount and allow the temp to coast up to 625F.  For most roasts I try
to keep the temp in that range especially up to 1st C.  With the TelTru, I
can actually see the temp falling off after 1st C has been reached and the
beans are not giving back as much heat.  Then just before 2nd C I can see
the temp creeping back up again as the beans start heading into 2nd.
A 20+ minute roast (for me) would be entering the "baked zone" which is why
it seemed strange to me for the RK drum.
Rick

6) From: RK
This is a multi-part message in MIME format.
a full 4 lb load of hight grown coffee that is dense using a grill that =
is only 36k will fall into a 20 to 22 min time. For larger 4 lbs batches =
IMO you should have a 45K grill.
I am still using the 36K grill I started with about 4 years ago and it =
struggles with 4 lbs batches to get to 2nd crack in under 20 min. I =
could block off some of the exhaust and this would help but I have not. =
I have not notice a big difference in a roast that goes 22 min but have =
in ones that go 25 min.
I do shoot for finish 20 min or less for 4 lb loads.
RK

7) From: Coffeenut
This is a multi-part message in MIME format.
Thanks Ron, that explains it and aligns with my experience when doing larger
batches.  I can do a max of 2lbs in my modified Alp drum and have to keep
the burners on full blast all the way through 1st C to keep the total roast
(including 1st few snaps of 2nd) within the 18min timeframe.
I've blocked off a few of the lateral holes and ports on my roaster to help
contain the heat and it does help (especially in windy cold weather).  I've
felt that if I could reduce the unused (unnecessary) area within the grill
and focus the heat to a smaller area that maybe it would require less gas
and energy than what I expend today  (sort of like you see in a sample
roaster design).  However, I've not done anything about that so far and what
I have is working which accounts for something.but I still dream.
Rick  
From: homeroast-admin
[mailto:homeroast-admin] On Behalf Of RK
Sent: Monday, January 22, 2007 9:20 PM
To: homeroast
Subject: +Re: Digirosto & roast times
a full 4 lb load of hight grown coffee that is dense using a grill that is
only 36k will fall into a 20 to 22 min time. For larger 4 lbs batches IMO
you should have a 45K grill.
I am still using the 36K grill I started with about 4 years ago and it
struggles with 4 lbs batches to get to 2nd crack in under 20 min. I could
block off some of the exhaust and this would help but I have not. I have not
notice a big difference in a roast that goes 22 min but have in ones that go
25 min.
I do shoot for finish 20 min or less for 4 lb loads.
RK

8) From: Justin Marquez
On 1/22/07, Coffeenut  wrote:
<Snip>
I use a candy thermometer from Pyrex (IIRC) which goes up to 500 Deg
F. It has a slim stem and responds quickly.  I got it at WalMart in
the kitchen gadgets section. I have it inserted to within an inch or
so of the drum about midway of the drum horizontally and about 2" off
center to the right (the worthless thermometer that came with the
grill is in the center). I also use the thermocouple setup on the left
side, similarly located.
I find that when the T/C reads about 270 C (518 F) that the Pyrex
themometer will read about 500 Deg F and that one with the grill never
gets over 400 or so. The T/C temp always bounces around quickly (+/-
10 Deg C) and the Pyrex one  follows pretty soon as the center point
of the "bounces" move up or down.  I normally try to keep the Pyrex
one at about 475-480. If I roast with the temp on it at or past 500
Deg, I get "divots" in the beans.
I use the temp on the Pyrex thermo as the target and use the T/C as an
advance indicator of how to adjust the burners as the wind varies and
as the endo- exothermic segments come and go. The indicated temp on
the T/C is really hard to hold steady. (But then it has been pretty
windy when I have been roasting since I got it a month or so ago.)
Safe Journeys and Sweet Music
Justin Marquez (CYPRESS, TX)

9) From: RK
This is a multi-part message in MIME format.
Snip: from Rick (coffeenut)
<Snip>
the grill and focus the heat to a smaller area
It is possible to build a lid inside the lid to greatly reduce the =
roasting chamber. Sheet metal or Aluminum a pair of snips and pliers. =
cut a card board template and transfer to the sheet metal. Cut slit, =
bend, to fit and attach with self tapping screws or rivets, I like the =
self tapping screws, no drilling holes required.
I have a friend in Atlanta that did this to his Fiesta grill and said it =
really made a difference in the gas needed to roast larger batch sizes.
Cheers
RK

10) From: Coffeenut
This is a multi-part message in MIME format.
Good point Ron and since this grill is dedicated to just coffee I can do
what I want with it.  I do have a lot of wasted space around that Little Alp
drum that's getting heated for nothing I feel.  I already need to tweak on
my cooling contraption and do have an "itch" to experiment with my roaster.
I have to confess to liking rivets just because I like doing them (in small
qtys of course).
Thanks,
Rick  
From: homeroast-admin
[mailto:homeroast-admin] On Behalf Of RK
Sent: Tuesday, January 23, 2007 5:50 PM
To: homeroast
Subject: +Re: Digirosto & roast times
Snip: from Rick (coffeenut)
<Snip>
grill and focus the heat to a smaller area
It is possible to build a lid inside the lid to greatly reduce the roasting
chamber. Sheet metal or Aluminum a pair of snips and pliers. cut a card
board template and transfer to the sheet metal. Cut slit, bend, to fit and
attach with self tapping screws or rivets, I like the self tapping screws,
no drilling holes required.
I have a friend in Atlanta that did this to his Fiesta grill and said it
really made a difference in the gas needed to roast larger batch sizes.
Cheers
RK

11) From: RK
This is a multi-part message in MIME format.
Rick take pictures so we can see the development of your roaster.
RK


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