I wanted to test my theory that vacuum sealing individual 18 gram doses of roasted coffee beans (versus storing them in a standard one-way valve coffee bag) would extend the number of days of what I call “peak freshness”. The latter phrase describes the number of days where I enjoy the fullest flavor of the espresso.

To test my theory I kept some beans from the same roast in a normal coffee bean storage bag with a one way valve and others in individual 18 gram dose vacuum sealed bags.

The beans were Kenyan “Lena AA” and were roasted on Monday 9th May 2022. The vacuum sealing was done on Tuesday 17th May which was when I guessed they were at the start of peak freshness. The beans were a dark roast and measured 64 on the Agtron scale as measured by a Tonino colour analyser.

My test pours were conducted on Thursday 14th of July 2022 so around 58 days or close to 8 weeks after vacuum sealing.

I made six espressos, three from the standard bag and three from the vacuum sealed bags. I used 18 gram doses for each one as measured on a calibrated Acaia Lunar. I used a Weber EG-1 set to the same dial point for each grind and I used a Decent DE1XL with the “Adaptive” profile for the pour. I used these two machines (EG-1 and DE1XL) because they offer the most consistency from the machines available to me. The espressos were all ground and poured one after the other so that there would be no significant change in room temperature or humidity from one grind/pour to the next.

In short, I tried to make every variable consistent, as far as reasonably possible, with the exception of the beans coming from either the standard bag or the vacuum sealed bags.

The results consistently showed that the vacuum sealed beans had disintegrated* faster than the beans stored in the standard one-way valve coffee bean bag.

(*I am not sure if “disintegrated” is the right word, maybe it should be “dried out” so feel free to suggest a more apt word/phase).

The two pics are typical of the pours. One pour each from the vacuum sealed pouches and the beans from the traditional bag. They pics are of the DE1XL screen and show that it took 15 seconds for the vacuum sealed beans to hit the 36 gram mark and 18 seconds for the beans from the standard one-way valve bag to hit the same mark.

My previous theory was that the lower amount of oxygen in the vacuum sealed bags would decelerate the disintegration of the beans. But the opposite has happened which leads me to think that perhaps the gas given off by the beans in the sealed environment is accelerating the disintegration in much the same way that a bunch of bananas contained inside a sealed plastic bag ripens faster due to the gas given off by the bananas being unable to escape.

In hindsight, this makes sense. And that’s the funny thing about hindsight: we are all so wise after the event but only a few seem to figure these things out in advance. I guess that’s why we need to test theories for ourselves rather than just take someone’s word for a thing, however logical their rationale may sound.

Anyone want to contribute their two bob’s worth?

Tom, when you vacuum seal the 18g bags, you you suck the bejesus out of them until they are a small hard lump?

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    DavecUK bejesus out of them until they are a small hard lump?

    Isn’t the same for all dry vac Dave ? Most of us may vac pack in 200g-250g as opposed to freezer storing on the sealed one-wave valve.

    Do you think the vac packing impacts the freshness negatively?

    I think @dfk41 and @Systemic did state that the beans go south faster - mostly within a month, I guess - after opening the vac sealed beans. Of course, the opened beans are stored in a suitable container and hence the environments are different.

    @tompoland Lovely post. Thanks for sharing your findings. We will never resolve this for sure! So, the key questions are as follows:

    • Are you saying vac packed beans are no good in terms of freshness?
    • How did they taste? This is the most important exam question, unless I missed reading this. Thx

        Tom, when you vacuum seal the 18g bags, you you suck the bejesus out of them until they are a small hard lump?

        I used to do this Dave but not any longer.
        I just suck most of the air out a couple of days after roasting and leave them like that for a week(ish).
        For longer frozen storage I use the little plastic take away containers that hold a perfect 18g.

        As a corollary, when I sous vide meats I don’t “suck the guts” out of them as I believe that it works to remove moisture from the meat while cooking.

        Tom, I think you should pose this question to Lyrebird.

        tompoland CAn I ask, how many days after roast you vac them? Personally, I with medium to medium dark beans often wait until 28 days past the roast date, or at a point when I am certain the settling process has finished. Every now and then I get this wrong and the beans produce a little CO2 but so what? If anything it can only helep. Perhaps I ought to try sealing then a few days after roast to encourage the beans to sit in a cak bag in CO2?

        https://www.suddencardiacarrestuk.org/2024/02/thank-goodness-for-madeira-cake/

            tompoland pretty much

            @LMSC I think this creates negative pressure, pulls oils/volatiles to the surface, negatively affects flavour and causes the beans to stale faster, especially when opened.

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                DavecUK but apart from that it’s a good idea?

                (Kidding)

                Sounds like it’s a really bad idea then 😕 🤔

                Thanks, as always, for your insights.

                  dfk41 depends on the roast depth. When I was vacuum sealing I would make an espresso a day from a fresh bag of beans and vacuum seal when they hit peak flavour, according to my taste buds which for dark roasts was typically around 10 days post roast. But your Dark Roast might be my Medium Roast.

                    DavecUK

                    • So, Vac Pack is probably a bad idea.
                    • Freezing the sealed one-way valve bag supplied by the roster may have its’ own problem!

                    I know there is a trade off! What do you think is the best strategy to store beans as most of us buy bulk?

                      LMSC for beans vac sealed at say day 10 post roast, and consumed within another 7 to 10 days, the flavor could be very good. But for the 8 week old beans in this test, both the beans from the bag and the vac sealed pouches were a long way past their “best by” date.

                          tompoland This is really interesting, thank you for posting.

                          I am still working towards a solution that I am happy with. It will never be perfect, but then nothing ever is.

                          I currently freeze beans in 250g bags. It is becoming a bit of a pain, especially this time of year, as our freezer isn’t very big. I also note the various thoughts on freezing (which I admit I have not fully explored - i.e. freeze 18g doses and grind from frozen).

                          Given @DavecUK recommends ‘sucking until its soft’, I wonder if using a ‘ziploc’ bag, squeezing as best one can, and then storing in an airtight container (i.e. an airscape) might also work.

                          I might give it a go. Break down the beans into 100g per bag as well.

                          Any thoughts based on your experience and everything else you’ve tried to date?

                          Cheers

                              PortafilterProcrastinator my latest thinking is to roast/buy enough beans once a week to last a week.

                              What I am trialling now is to roast a net weight of 450 grams every Saturday and rest it for 7 days and then consume over the following seven days. That way the beans are enjoyed while still at peak freshness. The beans begin to disintegrate (or at least, dry out) after 7 days as evidenced by needing to add a gram or two more beans in, to get the same volume out.

                              I freeze only when I have excess and if using frozen beans I grind while still frozen because that gives me the best flavour and viscosity. In my experience allowing frozen beans to defrost before grinding produces an espresso that is thinner and less flavoursome than when I grind frozen and immediately pour.

                              I’m really on a mission to be able to consistently enjoy the style of espresso that I like, which is the reason behind the constant tinkering and the O.C.E.D. (Obsessive Compulsive Espresso Disorder 😀).

                                2 years later

                                My two bob’s worth admittedly rather late to this particular party is what I read elsewhere, which did seem to make sense to me - “I am now finding good reason not to vacuum seal coffee! The “Off Gassing” of Co2 that the bean produces provides a protective barrier against oxygen, the oxygen that will eventually make coffee bean stale. In vacuum sealing the coffee this Co2 gets pulled from the bean prematurely, when the oxygen is let back in on an everyday basis to remove coffee beans for brewing and grinding, the Co2 is replaced with oxygen, causing premature aging of the bean… Just something to ponder!” I have not vacuum sealed beans myself as I don’t have the equipment

                                DavecUK fine, just suck till it’s soft

                                I can’t help wondering, something must be wrong. Suck and till it’s soft seem to create a lot of technique questions ☕

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                                  tompoland for beans vac sealed at say day 10 post roast, and consumed within another 7 to 10 days, the flavor could be very good. But for the 8 week old beans in this test, both the beans from the bag and the vac sealed pouches were a long way past their “best by” date.

                                  I think that the degradation may be due to the fact that:

                                  • For the beans that were vacuums sealed 8 days post roast: a) heavy suction has adverse affects on flavour (I experienced this as well), b) despite vacuum packing there is still 02 in the bag (in the crevices between the beans and in the pores of the beans) that has not been pushed out by C02, as there is no 1 way valve. But the cause of the adverse freshness impacts is more likely a) than b)

                                  • For the beans kept in the coffee bag, I am guessing that more of the O2 was pushed out by the CO2 generated by beans. The beans were protected by the C02 that they generated, and were not exposed to O2.

                                  • The best solution to staling is still to freeze the beans. So I lightly vac pack my beans in 3 day portions and freeze them. I do this at their peak freshness.

                                    Some things in daily life are taken beyond OCD and more along the lines of being anal retentive in nature. For awhile now I’ve been home roasting and my only regret is not doing it sooner than I did. Before that I did buy quality commercial roasted coffee in 5 lb bulk, let it ‘age’ 4-5 days post roast, then vacuum seal/deep freeze in Mason glass jars. Would simply apply just enough vacuum to notice the change in sound from the device and that’s it. Too much vacuum applied would likely pull oil to the surface, etc…. then would tighten the lid and put into freezer. Pull a jar out to thaw overnight and use within a few days. Can honestly say that even at 5-6 weeks out (if it ever lasted that long) it still extracted and tasted just like it was at the 4-5 day post roast point. Early on I knew for a fact that vacuum packing/deep freezing was legit when I experimented with decaf for espresso, which is quite simply annoying in a commercial setting as it degrades much quicker. I let some sit in freeze for about 7 weeks and it still behaved like it was days out of the roaster, so without question the process definitely serves a useful purpose. Main thing some people overlook is freshness as that’s key no doubt.

                                    I do not vac pack my beans before freezing. I freeze a whole 250g bag and then when I am ready to use them decant the frozen beans into screw top jars that hold 36g and pop them back in the freezer and grind from frozen. Going by what Tompoland has said I see no need to vac pack them….do I?

                                      Pompeyexile I’d say the ideal thing to do is try something to see if it works better for your scenario. Worst thing is strictly going by what others claim works/or not and never giving it a fair shot.