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Topic: aluminum for roasting (28 msgs / 641 lines)
1) From: john
does anyone know if aluminum is a safe metal to have in contact with beans at roast temperatures?  more specifically, i have an aluminum cookie sheet that i'd like to use as sheet metal for parts in fabricating a new drum.  the drum is cast iron, but i'm thinking of using the aluminum as an exit door for the beans.
however, if that's safe, it's got me thinking about using a turkey frying pot as a drum.  if it's ok for cookies, is it ok for coffee?  ...would be much higher temperatures.
thanks,
-john
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2) From: decrisce.md
Why wouldn't it be safe John. The only issue I could see is whether or not the sheet is thick enough to hold the heat. Keep in mind that many commercial pots and pans are significantly made of aluminum (with a copper base, as aluminum is not th best heat conductor). 
Dean. 
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3) From: Joseph Robertson
Safe? What does that mean John.
I don't like AI. I don't like it for much at all. Pretty good for conducting
heat and electricity. Cooking anything? I personally would not use it. Too
many other choices out there for me. Just my personal couple of pennies.
PS.I would roast green coffee over a camp fire in a cast iron skillet before
I would use Al for anything. In fact I have done it.
Joe
On Mon, Apr 12, 2010 at 7:35 AM, john  wrote:
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4) From: john
you know, i think i'm just paranoid about certain metals or alloys giving 
off harmful vapors when heated, galvanized metal for instance.
you make a good point about typical composition of pots and pans, which is 
why i turned to the cookie sheet as a possible safe choice.  i just want to 
make sure since they're not usually intended for such high heat 
applications.
-john

5) From: decrisce.md
I am certainly no chemist or metals expert, however still seems ok to me, given I have some aluminum pots which I used to use for roasting on direct gas stove fires, without any ill effect. 
Makes sense though to fire it up once to burn off any glaze or covering that may be present.
Dean. 
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6) From: Allon Stern
On Apr 12, 2010, at 11:34 AM, decrisce.md wrote:
<Snip>
and make sure it isn't a teflon coated sheet; those will exude poison gasses if heated to roasting temps.
-
allon
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7) From: Tom Ulmer
For a year or so I used an aluminum WhirlyPop to roast. Besides third eye
development I've noticed no ill effects.
I believe there was news a few years ago which attempted a correlation of
aluminum levels in the body to Alzheimer's disease.

8) From: cherry carter
But the ill effects may not be noticed for decades. Please read, "Slow Death
by Rubber Duck." This is a study by Canadian researchers who looked into the
potential problems of many everyday things that have become a part of our
lives.
I am still looking for an all stainless steel electric teakettle. So far
they are nonexistent because the manufacturers seem to include a bit of
plastic here or there. Plastic and heat do not react well with our bodies.
Cherry Carter
On Mon, Apr 12, 2010 at 9:16 AM, Tom Ulmer  wrote:
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9) From: Joseph Robertson
 I remember the, what I think was inconclusive studies on this. Technically
speaking I believe Al is considered a heavy metal even though it sounds like
an oxymoron. If the metal can enter my system through what ever method. I
will steer around using it. Remember the stove top little espresso makers?
They used to be made only of Al. Now many from Italy are Stainless.
Although the Al ones are still sold. I used to look down inside at the
decaying Al that looked like an oxidizing mineral decaying soup. Never will
I go back to and consume any amount of that questionable stuff. Give me good
Ole cast iron or stainless.
Nice for building some things not food related.
Don't mind my rambling memories. Give me a good cup of Joe and who knows
what I will ramble on about.????????????? ;)
On Mon, Apr 12, 2010 at 9:16 AM, Tom Ulmer  wrote:
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10) From: Ryan M. Ward
I am not a medical person, and my chemistry background certainly does not establish any sort of expertise. When I looked into the Aluminium/Alzheimer's issue, the impression I got is that Aluminium, although not the best thing for the body, does not enter the body easily. The advice that I consistently saw not to cook highly acidic foods with aluminium cookware(such as spaghetti sauce). I can tell you that the last position that I read from the Alzheimer's association stated that the hypothesis that Aluminum was a strong contributing factor leading to Alzheimer's appeared unlikely. (Again, I am not a doctor and have NO expertise on this, I am just a consumer passing along friendly information that I have accumulated- please verify for yourself)
Now, roasting-wise, what I would be concerned with is the "speed" at which the metal heats up and cools down and how that plays into roasting consistency. As I recall from memory, the specific heat of Aluminium is pretty low which means that the your bowl will heat up quickly and cool down quickly depending on the ambient temperature (Chemistry friends- please stop me if I say something stupid). This is what I would consider.
Now that I have commented on every technical subject that I am not an expert in, do you have any numbers that need crunching?
-- 
Ryan M. Ward
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11) From: Mike Koenig
A few points on Aluminum (or Aluminium if you are so inclined):
1.  It is the 3rd most abundant element on the planet, so avoiding it in
your diet is nearly impossible.  You get between 2-25 mg/day just by eating
normal food, which far exceeds any exposure you may get from your coffee
equipment.
2.  Uncoated Aluminum surfaces quickly form a layer of Aluminum oxide which
is remarkably stable and prevents solutions (such as water or coffee) from
attacking the metallic layer underneath.   The only way you MAY get some
aluminum dissolving in water (or coffee, beer or whatnot)  is to scour the
surface, then quickly expose it to the solution before the oxide layer has a
chance to form.
3.  The link between Aluminum intake from diet and Alzheimers is not widely
accepted (except by internet fearmongers), and even the Alzheimer's Society
states that there is no correlation, especially given the large amount
consumed on a daily basis in a normal diet in most of the population.
That being said,  I once used an Aluminum rod for a drum roaster on my
Grill, and found that it would bend if I let the grill get too hot,  so
maybe it's not the ideal metal for use in roasters.
--mike
On Mon, Apr 12, 2010 at 2:18 PM, Joseph Robertson wrote:
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12) From: Joseph Robertson
Ryan,
This thread in getting deep into some science I also have little or next to
no experience with.
Now to include the coffee and coffee making back into this thread, when I
made coffee with the stove top Al. Italian espresso makers years ago, I
always wondered if coffee or the acid nature of it durning the brewing
process could in some or anyway leach some of the Aluminum from the pot? Now
I use and promote stainless versions I don't think about this anymore.
At least I wasn't till this thread started.
;) Joe
On Mon, Apr 12, 2010 at 12:23 PM, Ryan M. Ward 

13) From: Joseph Robertson
Nice points of information mike.
I heard that we consume a regular about on a daily basis some time ago. I'm
most interested in limiting it in all forms as much as possible.
I personally can't accept something for my body just because it's impossible
to eliminate it totally. Mercury is another heavy metal that is very
difficult to remove once it is absorbed by the body. I am opting to remove
my mercury fillings. Probably won't help me enjoy coffee any more but it
will make me feel better to know they are no longer in my teeth.
Cheers,
Joseph
On Mon, Apr 12, 2010 at 12:58 PM, Mike Koenig  wrote:
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14) From: Sandy Andina
The danger of acid foods leaching aluminum from non-anodized vessels is purely aesthetic--it negatively affects taste and darkens stuff like tomatoes and citrus. No disease links have been proven, and research has been long and extensive. I use stainless simply because it doesn't corrode, maintains heat more evenly, and can be scrubbed six ways from Sunday. (And it doesn't warp as readily).
On Apr 12, 2010, at 3:05 PM, Joseph Robertson wrote:
<Snip>
Peace & song, 
Sandy 
www.sandyandina.com
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15) From: Rich
Ever look into the aluminum boiler on your espresso machine?
Joseph Robertson wrote:
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16) From: Rich
Aluminum melts/liquefies at ~1100F  and is plastic at ~950F.  As long as 
you are not directly heating the aluminum sheet it will be fine at 
roasting temperatures.
Mike Koenig wrote:
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17) From: Rich
Well, with stainless steel you should be worried about chromium.
Joseph Robertson wrote:
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18) From: Mike Chester
--------------------------------------------------
From: "Rich" 
Sent: Monday, April 12, 2010 5:36 PM
To: "A list to discuss home coffee roasting. There are rules for this 
list,available athttp://www.sweetmarias.com/maillistinfo.html"
Subject: Re: [Homeroast] aluminum for roasting
<Snip>
Only if you have a Gaggia.  Most machines use copper or brass for the 
boiler.  My La Marzocco uses stainless steel.
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19) From: Sandy Andina
The newer Gaggias--even the lower-end "Color" line--now have stainless boilers.
On Apr 12, 2010, at 5:00 PM, Mike Chester wrote:
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Peace & song, 
Sandy 
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20) From: Ryan M. Ward
How are those Stove top coffee makers? I have thought about getting one for some time. 
-- 
Ryan M. Ward
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21) From: decrisce.md
They are great and make a unique rich cup. Doesn't beat the aeropress IMHO, but gives you one other option for the brew. 
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22) From: john
i dont' think this made it through the first time, so... thanks again!
ok, so the concensus is that aluminum is fine in terms of vapor and direct
contact with a dry substance.
and, if i'm planning on using it for a door on the otherwise cast iron drum,
i should have no cause for worry (nicer word for paranoia).
thanks, all!!
-john
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23) From: mary deem
I love Italian stovetop espresso/moka pots.  I grew up with them so I am
biased...
They do not make espresso like an espresso machine-especially a pro-line
one...not the same intensity nor any crema really.  Having said that, they
do make a good espresso - just not compared to a pro espresso machine.  If
you get a larger one-say a 6 cup or larger, you can use it to make regular
strength coffee simply by adjusting the coffee to water ratio.  I use mine
for all the coffee brewed in my house!  They tend to work better over a gas
flame as opposed to an electric stove...takes longer on the latter.
Another wonderful item is a stove top milk steamer.  They used to be
plentifull, now they appear to be going the way of the dodo.  You can still
find them occasionally on E-Bay or Orphan Espresso.  They do a great job
properly steaming milk with just the right amount of froth.
Be wary of the newer stovetop espreso/steamer comboinations like Bellman.
They never have enough steam to froth the milk after brewing the espresso.
Stick with the older espresso and steamer combos or seperates.
Mary
On Mon, Apr 12, 2010 at 10:06 PM, Ryan M. Ward 

24) From: Phil Palmintere
I hadn't thought about it until now; maybe I'm getting old, or maybe it's
the exposure to aluminum.
Hot water heaters we all have in our homes are stainless steel tanks with an
aluminum rod suspended inside -- it is called the "sacrificial anode".  The
aluminum is consumed (<== highly technical term use) over the years instead
of the stainless steel of the tank (hence the word "sacrificial").  Once the
sacrificial anode is gone, then the stainless steel of the tank will go.
And the only difference between a hot water heater with a 6 year warranty
and one with a 12 year warranty is that the latter have *two* sacrificial
anodes.  
And of course they are replaceable; I change mine every 4 years just to be
safe.
Here's a picture of the rod - a new one, and an old one.  The old one only
shows the steel core wire left; all the aluminum has been consumed into the
hot water.http://www.waterheaterrescue.com/images/lranode1.jpgSo... do espresso machines have sacrificial anodes in their boilers?  My
guess is they don't.  Has anyone had a boiler go bad?
--phil
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25) From: raymanowen
"How are those Stove top coffee makers?"
Excellent.  Got a stainless steel 6 tasse model,  Fun trying different
techniques and methods; you'll like the results.
The "thermo block" that some espresso machines use has the heater element
and the stainless steel tubing between the pump and the valve/ group
assembly cast into an aluminum block.  The thermal and electrical
conductivity of cast Aluminum is the same order of magnitude as Copper.
Putzig (University of Colorado 2006) has published a model for Thermal
Inertia Units (*tiu)* as a derived SI unit...   As the name implies, thermal
inertia represents the ability of a material to conduct and accumulate
heat.  Most engine coolant is water-based.
Water is an excellent *tiu* component, better than the misleading market
palaver re: Marine Brass used in espresso machine groups and filter
handles.  Brass is easy to cast, polish and requires little finish
machining.  In that respect, the state of the art would advance if the brass
pieces were replaced with carbon fiber.  Brass Loses as a thermal mass;
Water has higher *tiu*.
Cheers, Mabuhay -RayO, aka Opa!
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Thing)
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26) From: Ryan M. Ward
"*Notis: This email was not sent using a Tesla 9.10 CPU (Croatian Karma Thing)"
Very nice! I would love to get my hands on a Tesla 9.10 CPU Croatian thing!
-- 
Ryan M. Ward
*Note: This email was sent from a computer running Ubuntu Linux 9.10 (Karmic Koala)http://www.ubuntu.com**Note: This signature was placed here by me and is not automatically-generated-annoying-end-of-email-spam placed here by anyone other than myself. I am a Linux nut and am doing my part to support open source software and the Linux and Ubuntu communities by getting the word out with each email I send, I encourage you to do the same.
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27) From: Yakster
I remember seeing a picture of a Calrod espresso heating element (coil type,
I believe) that had a superficial anode attached to it... someone was asking
what it was.
Here's a link to a Home-Barista post showing a sacrificial anode on a
heating element. I don't think this is the same post I remember, but it's
one of the first that came up in a web search.  There's a picture of the
anode in the message below.http://www.home-barista.com/levers/la-peppina-cleanup-progress-and-questions-t8054.html#p94139My uninformed guess is that many espresso machines probably forgo the anodic
protection.
-Chris
On Mon, Apr 12, 2010 at 9:41 PM, Phil Palmintere
wrote:
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28) From: raymanowen
"...espresso machines probably forgo the anodic protection."
Well- does your espresso machine boiler have to heat gallons of water by the
dozens with a 50K BTUH heater?  Be first on your block with an espresso
machine whose boiler will last a century.  The tertiary sacrificial anode
makes ions that go ¿where?
Cheers, Mabuhay -RayO, aka Opa!
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