[Homeroast] Storage with gasses; and the Behmor question

Mike Davis mldavis2 at sbcglobal.net
Thu Aug 28 12:51:19 CDT 2014


I must agree that this "technical" discussion is largely pointless. I, 
too, am a chemist (retired) so we all have a tendency to over-analyze 
such questions.  In simple, layman's language, what I do now is 
immediately place my freshly roasted beans in my AirScape with the inner 
lid handle up (opens tiny exit passages) to relieve any outgassing 
pressure.  The outer lid is on and closed with its exit valve available 
to vent accumulated pressure.  The interstitial space between the beans 
which is initially filled with normal atmosphere is mixed with 
outgassing CO2 from the beans, a process which takes about 12 hours or 
so, I believe (and I'm open to correction on that).  So the gas in the 
AirScape (O2 diluted with more CO2) can escape but no additional O2 
enters.  After 12 hours, I open the top lid, close the handle thus 
sealing the beans to circulation, and replace the top lid.  Then when 
I'm ready to use the beans (seldom more than 2 days unless it's an 
African that needs more rest according to Tom and others), I pour what I 
need into the hopper and reseal the remaining beans back in the 
AirScape. Granted, O2 has been re-introduced into the sealed beans, but 
it doesn't continually circulate until I open the lid again, and each 
time thereafter.  It's only slightly better than leaving all the beans 
in the grinder hopper where there is a limited but constant flow of 
atmosphere.  That's the best I can do aside from maintaining a nitrogen 
or Argon atmosphere, which I think is rather excessive unless you must 
roast a very large batch and keep it for a longer period of time than 
normal.  Roast only what you need.  Good discussion, guys.

On to the Behmor question.  John Nanci is technically right that you can 
actually create a new profile using the heater energy percentage 
controls and drum speed.  The trouble is that you can only do that (as 
far as I know - and again, I'm open to correction) within the timer 
limits of the existing pre-set profiles, so control is still limited by 
the timer, although you can extend the roast time with the "C" button 
and you should also have heater and drum control as well during that 
extension.  You cannot store those profiles in roaster memory for 
recall, so it's all manual control on the fly. What I'm waiting to see 
is a set of profiles that someone creates to better extract all that the 
beans have to offer.  The trouble with using a pre-set (or user defined) 
profile is that when you change beans, the profile doesn't necessary 
work exactly right.  Another problem is that there is no way that I know 
to link the heater energy change to the timer - it all has to be done 
manually by watching the timer and pressing buttons at the appropriate 
moments during the timer run.  The coasting effect makes such changes 
slow to take effect and so must be planned in advance along the roast curve.

So from a practical standpoint, you can't really create a profile as 
such.  What you can do is start with a lower bean mass (I run 1/2# on 1# 
settings), begin with P1 and then at a given time, manually change the 
heater energy percentage during the roast.  That's going to take someone 
a long time to figure out, much like running a train - you'll have to 
plan well ahead and know the lag times for each heater change, along 
with the optimum temperatures you need from the Behmor's sensors (or 
your own).  Again, thanks for the clarification, and I'm always open to 
corrections.

Mike Davis



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