HomeRoast Digest

Topic: All this need for hard scientific evidence is getting annoying. (10 msgs / 347 lines)
1) From: Kevin DuPre
I'm with Jim and Rich.  When I first joined this list
over a month ago there was a lot of good information. 
Any more it seems that everytime someone shares their
findings with the list, Ed needs to have "hard
scientific evidence" or it is passed off as anything
short of opinion or untruth to the point of being damn
antagonistic or confrontational at that.
My question is this. At some point in coffee roasting
to cite, only someone's experimentation, observation,
and sharing what they learned, so does that invalidate
all of what has been learned about coffee roasting
thus far? Hell, many of the best discoveries in the
world thus far have never had a formal publication
citing "hard evidence". Does that mean they never
I thought the point of this list was to further the
home roasting movement by sharing ideas, observations,
etc. from our experiences.
Basically what Ed is saying directly or indirectly is
that unless we can cite a peer-reviewed scientific
publication, with dates, times, graphs, EVIDENCE, and
data, even from our own experiences the information is
worthless to the list because it's only opinion. 
By that token, since I don't have any hard evidence
for the amount of control that my footswitch activated
relay modification to my Fresh Roast provides me, that
I really can't control the temperature - it's just my
opinion that I can. Perhaps the relay is not really
interrupting the current to the heater when it opens -
I mean, I saw the heater shut down and the temperature
dropped on the thermometer, and when I let go of the
footswitch the heater turned red again, and I was able
to hold the roast at a particular temperature by
alternating between the two, and I posted the results
of the modification on this list, but I can't cite
evidence - my e-mail post is the only "publication" -
so it probably never really happened :-)
Is the point of this list to obtain grant funding for
the next scientific breakthrough in coffee roasting
that we will make with our simple equipment and
methods, or to share what we have learned with like
minded individuals so we can enjoy our craft and move
it forward, COLLECTIVELY?
Ed's responses to the list like "I mean measurable
evidence.  Not literature.  Can you show me where the 
bean temperature is measured as higher than the heated
environment temperature? In Illy?  Davids? Sivetz? 
Not words.  Not opinion.  Measured data.  I've not
seen it." AND "I have only one problem with that.  Mr.
Staub didn't cite references to research backing his
claim.  Without a citation, it's just his opinion. Why
can we not locate hard research to show an exothermic
reaction?" serve what purpose? 
How about it Ed - how about YOU providing US some of
that hard research and evidence you are DEMANDING over
and over and over, since the industry pioneers can't
seem to produce it, and since we can't seem to find it
for ourselves to your satisfaction? 
I'm afraid if the tone of this list continues the way
it has been, I will also unsubscribe as apparently
some have already done.
I wonder what Tom and Maria think?
Kevin DuPre
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2) From: Dan Bollinger
Kevin,  That's not what I hear Ed saying.  He's saying (and correct me Ed if
I get this wrong), "Don't make a claim that roasts are exothermic reactions
until you can show it.  Repeating someone else's beliefs is not proof."
I'm with Ed.  I like impeccable language.  I reduces my need to make
assumptions about the speaker! :)  So everybody, here are the choices as I
see them.
1. I don't think roasts are not exothermic reactions.
2. I think roasts are exothermic reactions.
3. I know roasts are not exothermic reactions and my proof is...
4. I know roasts are exothermic reactions and my proof is...
5.  I have no idea.
If you pick #3 or #4 I will expect you to supply that proof.  In science the
proof falls on the person making the claim.  :)    Dan
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3) From: Dan Bollinger
LOL!  I think your #6 is really an extension of #5. As in, "I don't know,
and I don't care!"   ;)   Dan
Ed if
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4) From: Dave Huddle
6.  I don't care!
If the coffee tastes good, drink it!  
(a CHEMIST who did not enjoy P. Chem. or Themrodynamics courses)
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5) From: Irene and Lubos Palounek
"I wonder what Tom and Maria think?" wrote Kevin about the demands for hard
scientific evidence related to processes during roasting.  At this moment, I
think it is the most important question related to that subject. Tom and
Maria are paying for the space and bandwidth, so they should cut it off, if
they think it is too wasteful.
Otherwise, I think people should be free to ask questions and provide
whatever hard scientific evidence they want to provide. If I am not
interested in some topic, I can simply ignore those messages.  I have found
that responding to the messages I do not like simply prolongs their life.
If nobody responds, the thread will die its natural death. And I can ignore
it until it dies.
Remember, although the art of coffee is old, the science of coffee is an
At this moment, I neither have nor do I need any hard scientific evidence
that the coffee, while being roasted, turns from pale green to rich brown or
that some exothermic reactions are part of the roasting process ... in fact,
I do not need a scientific evidence about any chemical or physical changes
that happen during roasting. I do not need the scientific evidence. All I
want is some guidance: how to roast and brew coffee that tastes and smells
If other people need hard scientific evidence, I think that should be free
to provide as much evidence as they want; or ask for it ... once.
Regards, Lubos
Clipping from pages 48 through 49 of "The Book of Coffee & Tea" by Joel,
David, and Karl Schapira, coffee roasters in Greenwich Village since 1903
(ISBN 0-312-08822-1):
Unroasted coffee gives no clue as to what it might become. The beans do not
have the characteristic look, smell or taste of coffee. Most people do not
even recognize the contents of the freshly-imported bags. To understand this
situation, think what it would be like if all our bread came from a plastic
bag; we might not know what to do with flour.
A controlled application of heat brings about both physical and chemical
changes in coffee beans. When coffee is roasted it shrinks about 16 percent
in weight (up to 20 percent for the darkest Italian roast), doubles in
volume, turns from a pale green to a rich brown in color, and develops
characteristic coffee taste and aroma. A complex series of reactions is set
up, including decompositions and interchanges. The resulting chemical
composition differs radically from that of the green beans. At varying rates
and to various extents the constituent elements of green coffee are
decomposed. Those elements include water, oil, protein, caffeine,
chlorogenic acid, trigonelline, tannin, caffetannin, caffeic acid, starch,
sugars, fibrous material, ash, and traces of vitamins. The weight loss is
attributable to loss of moisture and of volatile decomposition products. The
remarkable increase in volume results from the beans popping and expanding
in response to heat: the higher (darker) the roast, the greater the volume
of any given weight of coffee. The color change is caused by carmelization
of the sugars. In darker roasts carbonization occurs and is responsible for
the distinctive flavor of such coffees.
The physical and chemical changes that contribute to the creation of coffee
taste and aroma are not fully understood. The caffeine component is quite
stable, showing a slight decrease only in the highest roasts. A large volume
of carbon dioxide is produced, some of it expelled into the atmosphere, some
held within the fibrous structure of the beans, where it is instrumental in
maintaining the aroma and flavor of the coffee for up to a few weeks.
Carmelized carbohydrates also contribute to flavor, as do the many organic
substances created and partially destroyed during roasting.
Chlorogenic acids, a class of the taste-stimulating phenolic acids, are
produced during roasting by the decomposition of aromatic hydrocarbons. They
and caffeine contribute to the pleasantly bitter taste in coffee. The true
tannins provide astringency. Trigonelline, a nitrogen-containing compound,
is found in about the same amounts as caffeine, but its effect is not yet
understood. Other organic acids abound. The acidity of coffee is highest
when treated to a fairly light roast-light-roasted coffee is more acid than
either green or dark-roasted coffee. This is because acids are both created
and destroyed during roasting, and in the light roast more acids have been
created than destroyed. The true tannins and the chlorogenic acids, for
example, are decreased by half in a heavy roast. Acids form only part of the
flavor picture, however, so it would be wrong to think that since light
roasts are highly acid, they are the most flavorful.
If the chemicals of taste are hard to pin down, the aromatics are even more
elusive. Extremely volatile aromatics are produced during roasting and
seventy distinct compounds have been identified in a distillate of these
substances. No single one is responsible for what every coffee drinker
recognizes and appreciates as coffee aroma. The mystery remains. We do not
as yet know what combination of what constituents makes coffee aroma. We
know only slightly more about what constitutes the taste of coffee. Though
the art of coffee is old, the science of coffee is an infant.
How does a coffee roaster judge the development of his coffee, that is, how
does he know when the required chemical changes have taken place? Here's
where the physical changes come in. The roaster bears the beans popping as
they expand; be sees the beans turn a rich brown color; he smells that smell
that smells like ... coffee. When a roast is just finished, when it's just
ready to be "taken off," the aroma promises something wonderful. All that
planting and shading and hoping and picking and cleaning and sorting and
shipping and selecting and now, just at that moment when he cuts off the
heat and pulls the lever to let the beans down into the cooling drum, he
knows he's done those beans proud ... when people come in and the aroma of
just roasted coffee bits them, they inhale deeply and smile. They know
they're onto something.
The fragrance of freshly roasted coffee is at once tantalizing and
satisfying, like a promise made and kept. Unlike purely sweet smells like
chocolate, perfume, or incense, the aroma of coffee is neither monotonous
nor overbearing. Like the beverage itself, the smell of coffee is
refreshing; it treats the nose to a stimulating sharpness, a pungency, that
offsets and complements the sweetness.
From pages 48 and 49 of "The Book of Coffee & Tea" by Joel, David and Karl
Schapira, ISBN 0-312-08822-1
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6) From: Jim Schulman
On 11 Sep 2002 at 11:36, Kevin DuPre wrote:
My take on what Ed thinks, certainly what I think, is that people who actually roast are too ready 
to believe what purports to be scientific information.
When Mike and Jim G gives me the how to on properly stalling a roast after the first crack, I 
believe them; when I read "If the EBT is diminished within this phase, there is a risk that the 
beanmass may begin to exotherm" or some such babble, my BS meter goes into the red zone. 
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7) From: Michael Vanecek
Holy sweet mother of mercy, I miss a few days and come back to a 
b&#chfest. Guys, this is a *homeroasting* list. Anything indicated or 
mentioned here can *only* be taken as opinion unless evidence is cited. 
If I state the sky is blue, unless I give evidence to that, it's my 
opinion. My Ugandan tastes great. Opinion - yours may suck for all I know.
Exothermic reactions be darned - we're here to enjoy coffee and 
discussion. Opinions can certainly be challenged to ellicit more 
information, but for crying out loud - we're not scientists here, we're 
*homeroasters*. If I make a statement, it's what I've come to believe. I 
don't in any way expect my belief to be taken as hard fact - but expect 
that it should always be taken as opinion, even if I'm spouting physics 
While there are a lot of very knowledgeable people here, I wouldn't in 
any state of mind take their statements as Word and I will always assume 
that it's an opinion they've formulated either by research, experience 
or from transmission to their aluminum foil hat. With all due respect, 
of course. If I desire elaboration on an opinion that conflicts with my 
opinion, I'll speak up and ask. In the end, it don't matter. The coffee 
still tastes great and tomorrow is a new day...
So, please, lets simmer down over a good cup of Joe, agree to disagree 
and get over the personal attacks and complaints. If Ed wants evidence, 
that's his business. If you don't want to give it, that's your business. 
Big deal - drink some good coffee and enjoy the fruit of your labors and 
know that whatever the case may be, this is some darned good coffee...
Be well,
Please - let's end the bickering...
-- http://dotfile.net/- Dedicated to Open Source Software
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8) From: Dan Bollinger
Lubos,  You're joking, right?  It's not like they get charged by the word.
You must be joking, 'cuz you then continue with 12 or 13 paragraphs.   :)
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9) From: Mike McGinness
From: "Dan Bollinger" 
 1. I don't think roasts are not exothermic reactions.
Aren't 1&2 the same thing, #1 using double negative?:-)
Home Ju-Ju Variable Variac Rockin' Rosto Roasting in Vancouver, WA USA
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10) From: Dan Bollinger
Oops!  I wanted #1 to say: 
1. I don't think roasts are exothermic reactions.
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