HomeRoast Digest


Topic: Roaster efficiency RE: +New "mid-range"Hottop model available (12 msgs / 419 lines)
1) From: Larry Johnson
Once again (I know you guys hate this), I am reminded of brewing beer. It is
necessary to boil beer for some amount of time in order to get certain
chemical processes to occur (extraction of lupulin from the hops, protein
coagulation, etc.). It would be more energy efficient if you were to boil
the beer with a cover over the kettle to prevent heat loss. However, anyone
who ever made that mistake probably made beer that tasted a lot like creamed
corn since the cover trapped the outgassing DMS (dimethyl sulfide) and
didn't allow it to escape. There are a few other off-flavors that come from
doing that, but DMS is the most prominent, usually.
Not saying that something like this will happen with coffee beans, but I
would think it's a real possibility. I think roasting probably does more
than brown the beans and caramelize the sugars. I would think it also
outgasses some nasty tasting stuff that we would just as soon get away from
the beans as soon as possible. But, I guess someone needs to prove this
empirically if it isn't already written up somewhere; we can speculate all
we want without proving a thing.
As Charles Barkeley once said, "I could be wrong - but I don't think so."
On 7/26/07, John Moody  wrote:
<Snip>
-- 
Larry J
The greatest pleasure in life is doing what people say you cannot do.  -
Walter Bagehot

2) From: John Moody
Commercial roasters install afterburners to comply with EPA toxic emission
regulations.. . . . .http://www.roastmagazine.com/backissues/septoct2006/blowingsmoke.htmlfor
starters
John

3) From: True, Dennis W. FC1 (CVN69)
This is a multi-part message in MIME format.
ok so my non-modified RK Drum roaster is or is not allowing enough
gasses to escape to prevent the harming of my beans?
I'm confused..
Dennis
 
V/R, 
FC1(SW/AW) Dennis W. True 
"Life Liberty and the pursuit of all who threaten it..." 
	Once again (I know you guys hate this), I am reminded of brewing
beer. It is necessary to boil beer for some amount of time in order to
get certain chemical processes to occur (extraction of lupulin from the
hops, protein coagulation, etc.). It would be more energy efficient if
you were to boil the beer with a cover over the kettle to prevent heat
loss. However, anyone who ever made that mistake probably made beer that
tasted a lot like creamed corn since the cover trapped the outgassing
DMS (dimethyl sulfide) and didn't allow it to escape. There are a few
other off-flavors that come from doing that, but DMS is the most
prominent, usually. 
	 
	Not saying that something like this will happen with coffee
beans, but I would think it's a real possibility. I think roasting
probably does more than brown the beans and caramelize the sugars. I
would think it also outgasses some nasty tasting stuff that we would
just as soon get away from the beans as soon as possible. But, I guess
someone needs to prove this empirically if it isn't already written up
somewhere; we can speculate all we want without proving a thing.  
	 
	As Charles Barkeley once said, "I could be wrong - but I don't
think so."
	
	 
	On 7/26/07, John Moody  wrote: 
		As the roaster becomes more efficient, undesirable roast
offgassing products
		such as formaldehyde and acetaldehyde are more
concentrated around the bean. 
		Not choosing recirculation is deliberate for some, and
poor efficiency
		accepted.  For the 8AM bean makers, pounds/watt is a
much higher priority,
		and the coffee in the cup gives some drinkers headaches.
		You could pull the packing out of an old Thrush for a
roaster project and 
		roast the beans for free during the commute to work.
That's real efficient.
		:-)
		
		John

4) From: John Moody
If it's in a standard grill, they "leak" enough not to worry.  Others will
consider experimenting with extra venting for various reasons.
I stopped HG/DB roasting because it was affecting my health, so I'm careful
now to reduce breathing the particles and gases coming off the roast.
John

5) From: Larry Johnson
Oh, I'm sure your non-modified drum is allowing the gases to escape just
fine - along with a bunch of heat. The others were proposing ways to make
the heat loss minimal by not allowing ANY exchange of air around the beans;
hermetic roasting, as it were.
.....or maybe not. I'm probably confused too.
On 7/26/07, True, Dennis W. FC1 (CVN69)  wrote:
<Snip>
-- 
Larry J
The greatest pleasure in life is doing what people say you cannot do.  -
Walter Bagehot

6) From: raymanowen
As my friend, Mike Krulik in Chi-town would say, sounds like a Polish snow plow:
"pull the packing out of an old Thrush for a roaster project and roast
the beans for free during the commute to work.  That's real efficient.
[If your plan was to clear the path of traffic immediately behind
you!] :-)"
If you're burning E85, the exhaust effluent is mainly H2O, CO2 and
heat- less of the latter with the higher compression ratios E85 can
tolerate.
The best starting point for a roaster design is probably the
afterburner. No discarding heat into the atmosphere.
High efficiency gas furnaces depend on reclaiming all of the heat from
the combustion gas exhaust stream and putting it into the domicile.
Cheers -RayO, aka Opa!
It's the Heat Exchanger- waste not, want not.
On 7/26/07, True, Dennis W. FC1 (CVN69)  wrote:
<Snip>
-- 
"When the theme hits the bass, I dance the Jig!" - -Virgil Fox at the
Mighty Wichita (ex- NYC Paramount) WurliTzer- 1976

7) From: Scott Marquardt
Yah, I was once wondering if the exhaust gasses from a propane motor used to
turn a drum could also fire it.   ;-)
Thinking about incompletely combusted hydrocarbons, though, has me wondering
again about ethyl mercaptan, the additive that makes propane smell. I gotta
wonder whether it burns completely. I'd think so.
And another thing -- there's sulfur in propane. Or at least, some propane.
I'd never've thought so, but I was once using propane for a very
unconventional purpose and noticed that sulfur was condensing and causing me
some trouble.
- S
On 7/26/07, John Moody  wrote:
<Snip>

8) From: Justin Marquez
Not exactly.  The combustion products of burning pure ethanol and air are
about :
70% Nitrogen
18% Water Vapor
12% CO2
C2H5   +  3 O2  (+ 11.3 N2)  ==>  2 CO2  + 3 H2O  (+ 11.3 N2)
(Obviously, E85 is not pure alcohol, but you get the idea - the largest
component in almost any exhaust system is Nitrogen, since about 79% of the
air is Nitrogen and other inerts.)
Safe Journeys and Sweet Music
Justin Marquez (CYPRESS, TX)
On 7/30/07, raymanowen  wrote:
<Snip>

9) From: Dan Bollinger
This is a multi-part message in MIME format.
Justin, that's a straw-man argument, right? The N2 is not involved in =
the combustion chemical reaction since it is goes unchanged and is not =
required, i.e. is not a catalyst. That's like saying one of the =
ingredients for cake batter is a wooden spoon!  You could extend your =
argument ad nauseum by including other gases present in air like Helium =
and Argon... Unless you can show that N2 chemically interacts with =
roasting beans I think you need to leave it out of the equation. 
Regards, Dan

10) From: Justin Marquez
You cannot ignore it in designing equipment to handle exhaust streams unless
you want it woefully undersized.
(Well, you don't bake the spoon into the cake. The N2 part of the air
certainly goes all the way thru the process and in some engines even reacts
to make a little NOX.)
On 7/31/07, Dan Bollinger  wrote:
<Snip>
-- 
Safe Journeys and Sweet Music
Justin Marquez (CYPRESS, TX)

11) From: Scott Marquardt
Understood; we're talking about thermal circumstances, and to the extent
that any nonreactive gas is present in large proportion, it's the equivalent
of thowing a couple pounds of bolts in with your beans and seeing whether
the roast duration changes appreciably.
On 7/31/07, Justin Marquez  wrote:
<Snip>

12) From: Justin Marquez
Well - from the standpoint of thermal effects, the N2 is just as hot as the
CO2 and water vapor. If you ignore it, then you are ignoring 75% or so of
the BTU's. The beans surely won't be ignoring it.
Safe Journeys and Sweet Music
Justin Marquez (CYPRESS, TX)
On 7/31/07, Scott Marquardt  wrote:
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