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Coffee Bags - One Way Valves or Not

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  • Coffee Bags - One Way Valves or Not

    Hi all,

    Here is my question. Does a bag fitted with a one way valve really make that much difference to the overall coffee at the end of the day?

    I am not talking small differences; I am asking if it makes a substantial difference that can be tasted/detected in the cup, both espresso, milk based espresso and filter/drip drinks.

    Even more so if someone was to purchase a bag of coffee and requested it to be ground does a one way valve really do anything?


    I am sure this topic has come up in the past. I have tried the search function but I dont feel the function on this site is very user friendly. It might be me so if someone can I provide assistance it would be appreciated.

    I look forward to hear youre thoughts on the positives and negatives for both bags fitted with valves and without.

  • #2
    Re: Coffee Bags - One Way Valves or Not

    The one-way valve provides an outlet for the outgas of fresh beans (without bursting a seal) and an easy way of expelling air after sealing.

    It may help ground coffee a bit--that I dont know, but given that ground coffee goes stale REALLY fast...

    Greg

    Comment


    • #3
      Re: Coffee Bags - One Way Valves or Not

      Gday Brew Time...

      If you type "one way valve bag" (without quotes) into the search bar, several thousand related posts are pulled up... :

      The intention is, to reduce the rate at which oxidation of the various compounds within the coffee, occurs. This is even more important if youre discussing ground coffee as the available surface area for oxygen to react with, is increased by several orders of magnitude. This reaction is part of the process which causes coffee to go stale and you will be able to detect the difference over time.

      If you are mainly concerned with whole beans then so long as youre concerned with only small amounts of coffee, say one days worth of consumption, then 1-Way Valve bags are not required. Larger amounts though, to be consumed over a period of a week or more, should be stored in these bags to reduce the rate of staling.

      All the best,
      Mal.

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      • #4
        Re: Coffee Bags - One Way Valves or Not

        Thanks Mal

        That is a very technically sound answer.

        Cheers

        Comment


        • #5
          Re: Coffee Bags - One Way Valves or Not

          Not to steal the thread but this relates to the bags as well.

          When you rest your freshly roasted beans in a one way valve the next day or so the co2 builds up and the bag swells with the gas, should you leave the bag like this or press the gas out? Sometimes while letting them rest I will tend to squeeze the bag to have a smell of the coffee from the valve.

          Comment


          • #6
            Re: Coffee Bags - One Way Valves or Not

            Squeeze away R0s.... ;D

            Nothing like that beautiful fresh roasted coffee aroma. I do the same thing...

            Mal.

            Comment


            • #7
              Re: Coffee Bags - One Way Valves or Not

              Has anyone had any experience with both the one way valve bags as well as the more environmental friendly paper bags with the steel tie at the top?

              Is there much of a difference in both after say 2 weeks of storing beans in those?

              I searched online and found that the paper bags, even those with plastic windows are cheaper than one way valve bags.

              I suspect though snobs swear by their one way valves as the best medium to store beans and are worth a little bit extra, and are re-usable.

              Gary at G

              Comment


              • #8
                Re: Coffee Bags - One Way Valves or Not

                Originally posted by 312B262735233B3131420 link=1311907924/6#6 date=1312213659
                Has anyone had any experience with both the one way valve bags as well as the more environmental friendly paper bags with the steel tie at the top?
                To answer your question...
                Yes, we did plenty of testing with paper, paper + valve, foil, foil + valve and some "kraft" bags that are hybrid paper and foil.

                The foil + valve were the best in all blind tests 2 weeks later.  In fact the ones we use are too good if you ask Fiefy.  She had to open all her bags a day before one of her overseas comps as the coffee was still too fresh 10 days after roasting!

                Originally posted by 554F424351475F5555260 link=1311907924/6#6 date=1312213659
                even those with plastic windows
                Windows are bad, sunlight speeds the process.

                Originally posted by 312B262735233B3131420 link=1311907924/6#6 date=1312213659
                the more environmental friendly paper bags with the steel tie at the top
                Dont be sucked-in Gary.  Those paper bags are bleached, lined with petrochemical plastic and are 100% unrecyclable.
                ...just cause it has paper on the outside doesnt always make it friendly.

                Comment


                • #9
                  Re: Coffee Bags - One Way Valves or Not

                  I just use freezer bags and put a few holes in them. Usually about 300g of beans for maybe a week or so. [smiley=huh.gif]

                  Any comments on that would be appreciated.

                  Comment


                  • #10
                    Re: Coffee Bags - One Way Valves or Not

                    Originally posted by 677E6F6F0A0 link=1311907924/8#8 date=1312267395
                    I just use freezer bags and put a few holes in them. Usually about 300g of beans for maybe a week or so. [smiley=huh.gif]

                    Any comments on that would be appreciated.
                    Sorry uh, what do you want us to comment about? Perhaps a question might help?

                    Comment


                    • #11
                      Re: Coffee Bags - One Way Valves or Not

                      Originally posted by 6E776666030 link=1311907924/8#8 date=1312267395
                      I just use freezer bags and put a few holes in them. Usually about 300g of beans for maybe a week or so. [smiley=huh.gif]

                      Any comments on that would be appreciated.
                      I think Andy has covered all the relevant bases....

                      Mal.

                      Comment


                      • #12
                        Re: Coffee Bags - One Way Valves or Not

                        We have talked about roasted coffee, he is a new thought.

                        What are the thoughts of fellow roaster in regards to storage of Green Beans in say 1-5kg Oneway valve bags as an alternative to calico/cotton bags.

                        Comment


                        • #13
                          Re: Coffee Bags - One Way Valves or Not

                          Originally posted by 4C59181E182D0 link=1311907924/11#11 date=1312437839
                          We have talked about roasted coffee, he is a new thought.

                          What are the thoughts of fellow roaster in regards to storage of Green Beans in say 1-5kg Oneway valve bags as an alternative to calico/cotton bags.
                          I dont see the need for the valve for green beans.

                          I think a valved bag could also possibly make the green beans sweat in certain conditions and Im sure that would be bad.

                          I have heard of some green beans being packaged in vacuum sealed plastic bags, but from memory these were CoE beans and pretty expensive, so how they were handled and stored would have been high on the purchasers priorities.

                          I use a combination of the bags that CS beans come in and old 5kg basmati rice calico bags. These have served me very well to date.

                          I suppose if you were looking to hang on to your greens for more than 3 years, then some sort of sealed bag might be an option, but mine dont survive that long!

                          Brett.

                          Comment


                          • #14
                            Re: Coffee Bags - One Way Valves or Not

                            Yeah, thats correct Brett... CoE and some others come in a multi layer foil/plastic material that is nitrogen flushed and vacuum sealed. MTC did it for a while on a couple of bin lots but have since moved to grainpro instead. I can only guess because the vac bags are expensive and quite fragile... a bump and they hole sucking in the air. Some growers also pack mid grade beans in this packaging to justify a higher price.
                            :

                            Grainpro is a plastic that lets moisture out but not in and doesnt leach petrochemical odours into the product (like many other plastic bags do) but if they are left in the sun they will still sweat and then mould the beans. Grainpro is a great way of transporting beans from origin as it will protect them from other "stuff" in the same shipping container.

                            Long term storage in hessian/jute/hemp bags will result in the smell of the bag getting into the beans. Worse if the bags get damp... think "wet dog"... not yummy.

                            The unbleached cotton that we use is close to the perfect storage material as it breaths but has no real odour to pass onto the beans.

                            CS Cotton in a cool, dry, dark area is a great storage medium. (tis no accident that we continue to use it!)
                            8-)

                            Comment


                            • #15
                              Re: Coffee Bags - One Way Valves or Not

                              Originally posted by 5C7379641D0 link=1311907924/13#13 date=1312444933
                              Yeah, ...
                              CS Cotton in a cool, dry, dark area is a great storage medium.  (tis no accident that we continue to use it!)
                              8-)
                              And that I guess is the reason many a CSr recommends and uses linen press as domestic green bean store   ;D

                              Comment

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