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? Thanks, Tim
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.
Tim 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 Josh On Nov 27, 2007 9:23 PM, Tim Harvey wrote: <Snip>
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*********************
Thanks to all for your input, The voice of experience is the best advice!
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... Bill On 11/28/07, Tim Harvey wrote: <Snip>
In a nutshell, no. CO2 is considered inert and protects the beans from oxygen. Kona Kurmudgeon miKe mcKoffee www.mcKonaKoffee.com 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/ <Snip>
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 .
On Nov 28, 2007, at 9:32 PM, Bill Hill wrote: <Snip> I think the defect is grassy flavor. pecan jim
"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: <Snip> -- "When the theme hits the bass, I dance the Jig!" - -Virgil Fox at the Mighty Wichita (ex- NYC Paramount) WurliTzer- 1976
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 day. 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... Lynne Barry Luterman wrote: <Snip>
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: <Snip> -- Larry J
"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: <Snip>
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*********************
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: <Snip>
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 agitation. 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! -ro On Nov 30, 2007 10:47 PM, Homeroaster wrote: <Snip> -- "When the theme hits the bass, I dance the Jig!" - -Virgil Fox at the Mighty Wichita (ex- NYC Paramount) WurliTzer- 1976