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  • Coffee air travel

    To reduce bean degradation in aircraft pressurised cabins, suggest sealing tape over bag air in/outlet

    Panda

  • #2
    Re: Coffee air travel

    Even more importantly if the coffee bag is in the luggage hold which is not pressurised.

    Comment


    • #3
      Re: Coffee air travel

      Originally posted by 5864796268697E6B63680C0 link=1235102776/1#1 date=1235105695
      Even more importantly if the coffee bag is in the luggage hold which is not pressurised.
      Nope. Cargo/luggage holds of pressurised aircraft are pressurised. Only exceptions are a couple of the smaller commuter/bizjet aircraft that may have a small baggage hold outside of the pressure cabin.

      Unpressurised baggage holds would make it hard for pooch to survive the trip.

      Comment


      • #4
        Re: Coffee air travel

        Originally posted by 444B4E101F1A290 link=1235102776/2#2 date=1235124806
        make it hard for pooch to survive the trip
        And here I was thinking they wore little oxygen masks. ;D

        Comment


        • #5
          Re: Coffee air travel

          Originally posted by 303F3A646B6E5D0 link=1235102776/2#2 date=1235124806
          Cargo/luggage holds of pressurised aircraft are pressurised. Only exceptions are a couple of the smaller commuter/bizjet aircraft that may have a small baggage hold outside of the pressure cabin.
          I wasnt necessarily thinking of passenger aircraft.

          If I Express Post a bag of coffee to Tasmania I expect it will go by plane.
          That plane may be cargo only.
          Is there a chance then that the cargo hold will be unpressurised?

          Comment


          • #6
            Re: Coffee air travel

            Most Aust post and courier flights use commercial passenger aircraft (Qantas,VB etc). Some companies do have dedicated cargo aircraft, but these are pressurised and are used for longer trips O/S or between major cities and regional centres.

            There are some smaller cargo aircraft that operate to more rural areas/smaller airports and these are not pressurised. However they dont fly very high - about the same altitude as the cabin altitude (pressure setting in the cabin) of your passenger flights (6-8,000 ft).

            A trip to Tas from Sydney would be on a commercial pressurised flight.

            Comment


            • #7
              Re: Coffee air travel

              I did even think about this until I took a few plane trips in June last year. When I opened my bag at the hotel my coffee bags were vacuumed sealed. so they must be pressurized. It was probably good for them anyway as I only roasted the day before I left so it got rid of that CO2 build up.

              Comment


              • #8
                Re: Coffee air travel

                With the exception of aeromedical aircraft operating with a sea-level cabin for medical reasons, all air travel is going to result in a change of temperature and pressure.  

                Depending on the aircraft and operator, some cargo holds may be heated (if livestock or known perishables such as fresh flowers are being carried).

                The vacuum-packed effect results when an coffee bag that has equalised with the cabin altitude (pressure) in the cruise returns to sea level.  The increasing pressure outside the bag as the aircraft descends squeezes the air out.

                So...the question is...how effective is the one-way valve in preventing air re-entering the bag as the aforementioned effect isnt really what the coffee bag has been designed for.

                Anyone experimented?

                <edited for clarity>

                Comment


                • #9
                  Re: Coffee air travel

                  Originally posted by 6F5A43491D1C2A0 link=1235102776/7#7 date=1235226790
                  how effective is the one-way valve in preventing air re-entering the bag?
                  Thats what theyre designed for.
                  If I squeeze the air out it doesnt get back in.
                  What does it matter if the external pressure is air pressure or my hands?
                  Once the air is out and the external pressure is removed, the bag stays as is.

                  Comment


                  • #10
                    Re: Coffee air travel

                    Originally posted by 665A475C565740555D56320 link=1235102776/8#8 date=1235228430
                    Thats what theyre designed for.
                    Not sure youre getting my drift there TG.  

                    - Your hands squeezing air out is in the direction of intended air travel. Its the opposite way thats being discussed.

                    - The valve is designed to an operating tolerance.  The kind of pressures its deemed likely to experience in normal operation.  The effect described is far greater than merely sitting around the kitchen and allowing occasional CO2 pfffts (a technical word) out :P  Whilst Ive never cut one open, Id assume its akin to the one-way valve of a whoopie cushion...pretty damn primitive really.

                    For example: just because an underwater camera housing that you buy at BCF is designed for submerged use, it doesnt mean it will function/stay sealed at a depth of 100m

                    Comment


                    • #11
                      Re: Coffee air travel

                      The lower air pressure in the aircraft causes the gasses in the bag to expand. When the required pressure difference between inside/outside of the bag is reached, the valve is pushed open and the excess gasses inside are released.

                      As the plane descends the outside pressure increases and compresses the bag. If the bag is very full there is not much gas inside and the bag is quickly tight against the beans.

                      I would assume that at some pressure difference (low in the bag, high outside) the one-way valve will fail and let air in. This seems more likely to happen with full bags.

                      We need a research project to determine the failure pressure of the one-way valves. I suggest we put a proposal forward to a university/government/commercial body, and see how many thousands or millions of dollars theyll give us. ;D

                      Failing that, if you want to ensure no air entry, seal your travel bags only half-full.

                      Greg
                      (Taking home roast to Canada in May.)

                      Comment


                      • #12
                        Re: Coffee air travel

                        Originally posted by 7F4A5D5F6F574A5559545C380 link=1235102776/10#10 date=1235261448
                        The lower air pressure in the aircraft causes the gasses in the bag to expand. When the required pressure difference between inside/outside of the bag is reached, the valve is pushed open and the excess gasses inside are released.

                        As the plane descends the outside pressure increases and compresses the bag. If the bag is very full there is not much gas inside and the bag is quickly tight against the beans.

                        I would assume that at some pressure difference (low in the bag, high outside) the one-way valve will fail and let air in. This seems more likely to happen with full bags.

                        We need a research project to determine the failure pressure of the one-way valves. I suggest we put a proposal forward to a university/government/commercial body, and see how many thousands or millions of dollars theyll give us. ;D

                        Failing that, if you want to ensure no air entry, seal your travel bags only half-full.

                        Greg
                        (Taking home roast to Canada in May.)
                        As I currently need a job Im willing to run the project for a modest six figure sum.

                        As for what to do in the meantime, a piece of tape over the valve seems to be the common practice.

                        Comment


                        • #13
                          Re: Coffee air travel

                          Originally posted by 5E6B72782C2D1B0 link=1235102776/7#7 date=1235226790
                          So...the question is...how effective is the one-way valve in preventing air re-entering the bag as the aforementioned effect isnt really what the coffee bag has been designed for.

                          Anyone experimented?
                          I havent experimented, but I have heard people band about 1/3rd as a figure for the failure rate for valves on coffee bags in normal operation.

                          Cheers,

                          Luca

                          Comment


                          • #14
                            Re: Coffee air travel

                            Last time I flew with beans I simply pushed as much air out of the bag as possible and then wrapped the bag with some tape to stop the bag expanding. Seemed to work.

                            Comment


                            • #15
                              Re: Coffee air travel

                              Originally posted by 4D544240210 link=1235102776/12#12 date=1235277966

                              I havent experimented, but I have heard people band about 1/3rd as a figure for the failure rate for valves on coffee bags in normal operation.
                              Ive gone through a few hundred now and only come across one faulty one so far.

                              Comment

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