I have an update on my attempts to increase the batch size with the Quest.
I am using Thermocouples, an Omega Temp Data Logger, My laptop running
Artisan Software and a Master Pro LED heatgun to assist the Quest.
Here are my findings:
I have had success in increasing my batch sizes up to 260g (I have not
gone higher yet but think I can get to 300g without killing the flavor
profile). Flavor profiles are close to 125g batch sizes. I hope
others will replicate my methods and report their findings.
My hypothesis has been that length of roast is a leading contributor
to flavor profile assuming you start at the same charge temp (400f),
time length from Charge to C1 is 6.5 minutes to 7.5 minutes, and
maintain a 4-5 minute time length between the start of 1C and 2C. The
challenge here is getting the roaster to act the same regardless of
batch size. I only have limited amounts of the Jimma that will return
the bleuberry toaster waffle flavor and am saving this until I have
this process refined more. For me, this particular coffee is the bean
which shows the highest level of flavor change depending on roasting
technique. If someone would like to suggest a different bean, please
let me know.
The real challenge here is ET temperature stability and the ability to
increase the temp when the temp is low or the charge weight overpowers
the heating elements.
Basics of this are to keep the amps high, increase the fan speed as
long as you can keep ET stable or rising up to 6.5. As batch size
increases above 200g, after about 1.5 minutes, I supplement the heat
with the heatgun (stuck down the tryer hole) until the BT is around
300f. Then I let the roast run it's course. I try to keep the ET
between 625f and 650f. as I hit 1C I open the fan up and cut the
amps. usually to around 7. Now, I do tweak the amps and fan all the
way through depending on the curves I see on the computer . It the
temp is falling I increase the amps, if it is increasing I cut the
amps (please note these are very small adjustments). Outside of
during C1 the fan doesn't exceed 6.5. I have concerns it will dry the
beans out above that. Also, I am able to increase and decrease the
temps with the amp control at 6.5 faster. Often I ramp the heat up
after C1 depending on the rate of fall for ET.
The cool thing this technique is if you have a tender bean (like the
Jimma) you know you need to extend the time from C1 to C2 you cut the
ET at the 6 minute mark regardless of batch size. You can use 125g
batches to work up the best roast profile and then increase batch size
and replicate the roast.
I am continuing to work this.
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