HomeRoast Digest

Topic: What are the odds of a co2 explosion..... (16 msgs / 270 lines)
1) From: Tim Harvey
Calling all coffee engineers:
Looking to make sample packs for my friends, and single use decaf packs for my church. If I put a 2 oz sample (or a smaller 14 gram sample) of cooled, just roasted coffee in either a 4"x6"x2.25" gusset pouch bag, or a 4.25x6.5" pillow pouch bag, and heat sealed it with no valve, what are the chances the de-gassing would pop the bag?  Would holding the co2 in help retain freshness, or harm the flavor? If you think bursting or flavor problems would result, would leaving the coffee in open air for a period of time (few hours) allow degassing without deflavoring?

2) From: Zara Haimo
I vacuum packed several bags of just roasted coffee for a trip.  Each had 
about half a pound and was sealed right after the beans cooled as I had no 
time to let it de-gas before traveling.  Within a couple of days, the bags 
had inflated and looked like fat pillows, but they never burst.  Even after 
3 weeks on the road, when I opened one of the bags, the coffee was still 
quite good as no oxygen had gotten in.  I suspect the CO2 had kept the 
coffee from going stale.

3) From: Robert Joslin
     From what I have read bean outgassing varies with variety, degree of
roast and total roasting time.  Generally lighter roasts outgas more, darker
less.  With such a small mass of beans (2 oz), if your packaging material is
fairly sturdy, you shouldn't have a problem with the bag rupturing.  If you
have the time, allowing the beans to outgas for about 8 hours before
packaging should avoid any problem.  My roasts are on the lighter side and I
vac package approx 8 oz of freshly roasted beans.  Sometimes I have a really
nice firm pillow after a few days, but I've never had a bag
rupture.  Sealing without vac will obviously result in more inflation due to
residual air. Its always so nice to cut open an inflated container of beans
and smell that wonderful aroma!
Happy Roasting
On Nov 27, 2007 9:23 PM, Tim Harvey  wrote:

4) From: Homeroaster
If you are sending it somewhere and it might go on an airplane, you'll need 
to poke a pinhole somewhere or it will pop.
That's the real reason one way valves were designed.  Relieve the pressure 
without letting air in.
Ed Needham
"to absurdity and beyond!"http://www.homeroaster.com*********************

5) From: Tim Harvey
Thanks to all for your input, The voice of experience is the best advice!

6) From: Bill Hill
Isn't there an issue, however, with the co2 giving the beans an "off"
flavor?  Isn't there a specific defect known as a "gassy" flavor,
indicating that the co2 gave the beans an off note?  I thought I heard
something about that, but can't remember where...
On 11/28/07, Tim Harvey  wrote:

7) From: miKe mcKoffee
In a nutshell, no. CO2 is considered inert and protects the beans from
Kona Kurmudgeon miKe mcKoffee
URL to Rosto mods, FrankenFormer, some recipes etc:http://www.mckoffee.com/Ultimately the quest for Koffee Nirvana is a solitary path. To know I must
first not know. And in knowing know I know not. Each Personal enlightenment
found exploring the many divergent foot steps of Those who have gone before.
Sweet Maria's List - Searchable Archiveshttp://themeyers.org/HomeRoast/

8) From: Barry Luterman
I leave my fresh roast out only for an hour or two. Then I close them up in 
a sealed canister with a gasket but leave 1/8 to 1/4 empty. I   figure CO2 
is heavier than O2 and will fill the gap between the lid and the beans thus 
protecting the beans from the dreaded O2. Of course then they wouldn't let 
me take Chemistry in high school for fear I would blow the school .

9) From: Jim Gundlach
On Nov 28, 2007, at 9:32 PM, Bill Hill wrote:
I think the defect is grassy flavor.
     pecan jim

10) From: raymanowen
"Isn't there a specific defect known as a "gassy" flavor..."
I'm able to clear rooms with my gassy defects. Remarkable after one of
Chubby's spicy green chili bean burritos... -ro
On Nov 28, 2007 8:32 PM, Bill Hill  wrote:
"When the theme hits the bass, I dance the Jig!" - -Virgil Fox at the Mighty
Wichita (ex- NYC Paramount) WurliTzer- 1976

11) From: Lynne
I did - well, it wasn't the whole school - just my experiment in lab. The
explosion actually melted most of the polyester dress I was wearing that
Of course, I the teacher gave me an apron RIGHT away, and I thought the
whole thing
was so funny - plus, I got to go home to change - and got out of the rest of
my Chem class.
Best day ever...
Barry Luterman wrote:

12) From: Larry Johnson
Closest I came was firing a rubber stopper across the chem lab during
a demo of the production of NO2 (High School Chem 1).
On 11/29/07, Lynne  wrote:
Larry J

13) From: raymanowen
"the co2 giving the beans an "off" flavor?"
CO2 couldn't give brewed coffee any flavor- off, on, up, down, port,
starboard, inside or outside.
There are three things about brewing coffee that tend to retard the
absorption of CO2 by the  coffee [if the coffee can't absorb it, you can't
taste it]:
1.) It's near boiling temperature of the H2O-
2.) The physical agitation involved in the process-
3.) The H2O is already nearly saturated with coffee chemistry.
To prove #1, call your old HS Latin teacher from a pay phone wearing gloves.
Have him put a 1L full plastic bottle of Dr. Pepper in his microwave. 180
seconds at full power should get it near coffee sipping temperature.
#2- Physical agitation- Have him open the door if it's still on the hinges,
and shake the hot bottle a few times- only so long as the bottle remains
intact. Have him stop shaking it just short of disintegration.
#3- Consult CRC Handbook of Chemistry and Physics. Otherwise it's a mystery.
Cheers, Mabuhay -RayO, aka Opa!
Fire extinguisher- Makes a Great Gift...
On Nov 28, 2007 8:32 PM, Bill Hill  wrote:

14) From: Homeroaster
Au contraire.  Residual CO2 in the liquid could affect the way the flavors 
and body of coffee are perceived.  I base my argument on the similarity to 
carbonated beer.  A stout, before it is carbonated, either artificially or 
naturally, will be flat, lifeless and dull, and perceived quite differently 
than one that has been carbonated (or nitrogenated, as in the case of 
Guinness and a few others).  Of course it is tasteless in itself, but it can 
affect the way flavors are absorbed by the taste buds and the overall 
perception of liveliness and brightness.
I would also argue that the sudden depressurization of espresso as it leaves 
the ~130psi portafilter 'carbonates' with the available CO2 in the grinds, 
and effervesces the mixture to give it the crema and the wonderful, lively 
taste.  A poorly pulled shot, with no crema, and likely no carbonation dies 
on your tongue.
Ed Needham
"to absurdity and beyond!"http://www.homeroaster.com*********************

15) From: Rich
Au contraire.  Water temperature above 170 degrees or so will degas the 
liquid.  There will be no dissolved gases in the hot coffee in the cup.
Homeroaster wrote:

16) From: raymanowen
Don't snicker as you encounter your old Latin instructor, who proved that
carbonated liquids can't hold their gas at high temperature or with
That's exactly the opposite of normal solvent/solutes.
Want to dissolve sugar in tea? Heat it and stir it.
Want to see a veritable explosion as CO2 leaves a solution? Heat and stir!
On Nov 30, 2007 10:47 PM, Homeroaster  wrote:
"When the theme hits the bass, I dance the Jig!" - -Virgil Fox at the Mighty
Wichita (ex- NYC Paramount) WurliTzer- 1976

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