HomeRoast Digest


Topic: Tom: please help re: roast recommendations (2 msgs / 84 lines)
1) From: Jay Kurtz
Tom, the more I think about it, the more curious I am. If you don't mind
sharing, what is the roasting "profile" you use when determining the
recommended roast degree (e.g. "past first crack but before second").  I
really think the type of roaster my have some impact on this. For
instance, how many minutes till cooling begins?
thanks for your time		
Jay Kurtz (jpkurtz)

2) From: Tom & Maria
<Snip>
I had sent an email on this but I dont see it on the list. Maybe it is "in
route".
I would like to share a couple thoughts on roast profile, roast methods and
freshness. Basically, unless you invent your own roast system, a lot of
things have been decided for you already. In terms of shop drum roasters of
the $12-20,000 variety: you have some controls that allow you to push the
roast along more aggressively or to hold it back a bit. You can use heat
and/or air flow to fiddle with the roast profile to some degree. But the
BIG differences are in the materials and design of the roaster.
I dont think I am disregarding the craft of roasting when I say this ...to
me theres a lot fore involved in selecting the good coffee that goes into
the roast system, and cupping the roast results to get that right "degree
of roast" for that particular coffee than there is to some technical
specification in the roast cycle that rings all the bells and optimizes the
cup. I think theres a lot of talk about roast profiling from people who
sell the equipment. But the fact is, crappy coffee in = crappy coffee out.
More importantly, very few roast operations handle the coffee appropriately
after roasting. Coffee should be in a valve bag within 1/2 hour of roasting
to take advantage of the major outgassing of CO2. And it should be FRESH
coffee!
Your average wholesale operation doesnt do this, and lots of shops dont
keep ALL their 50 varieties of origin, blend, flavored and decaf FRESH, and
they store it in bins anyway (my point here  is also that shops offer too
many choices).
Engineers need to think about roast profile but the FIRST thing roasters
need to think about is degree of roast, storage and freshness. Those MAJOR
QG variables are all well within the domain of the home roasting activity.
Okay, roast prtofile: nobody has THAT much control over it and in general
home roasters have a little less: we are either roasting on appliances that
have limited controls or we have modified something else to roast coffee.
Air roasters: profile is not so esoteric as drum roasting: put a
thermocouplke in your roaster and you will see that bean mass doesnt count
for much ...its all in the air flow and air temp. the term "forced air"
roasting really conveys what is happening; you are superheating the coffee
in a rapid air flow and the beans "do what they are told" in terms of
roasting. Compare that to the intricacies of a drum roaster: too much heat
too fast = scorched coffee, uneven roast. Too slow = baked coffee, dried
out. You have to slowly allow the coffee to take on heat by conduicting it
through hot surfaces or by radiant of convective heat but the coffee is
really PART of the roast system in its ability to aquire and transfer heat.
SO ...you have very different roast times. In air roasting my opinion is
that you want a slowly rising roast curve with the coffee at 335-350 at 5
or 6 minutes and 415 at 6.5 to 7 minutes. With a conductive roast you want
first crack at 335-350 between 8 minutes and 11 minutes and 2nd by (415 os
so) by around 14 minutes.
This is why I call the Alp a slow roast system, but you can use the coffee
weight as a variable to push the roast. I roast either 6 or 7 ounces. Its
still a bit slow, but judging by results it has great development of the
body. Centrals have a bit less pizzazz from the Alp, but you can still
roast acidy bright coffees nicely: I would chose the real powerhouse ones
like Kenyas, Panama Lerida,e tc...
Anyway, one of this here is tech talk, its just experience and I am no
engineer, beleive me!
And, finally to answer your question, the roast reviews are really based on
air roasts at a City and a Full City roast (I always do both to each
sample), but as stated, degree of roast is much more important than the
type of roaster or profile...
Tom
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