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Thread: Re-useable Vacuum Sealer Bags

  1. #1
    Bean Powered Member jaybee's Avatar
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    Re-useable Vacuum Sealer Bags

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Could this be the answer to the perennial how do I store my coffee problem?

    I spotted this vacuum sealer advertised by Big W for $59, but bought mine from e-bay for 15+10 and to me is the ideal bit of kit. Why?
    • The bags are resealable
    • The vacuum can be drawn to any pressure – if you are worried about having an outer-space like vacuum and losing those vital oils, worry no further.
    • The seal caps will simply blow off if you forget to draw off your excess CO2 and can be ‘sucked out’ *further when needed.
    • There are three bag sizes, and the small ones in the photo are just right for popper sized roasts.

    At least this was a cheap toy – time will tell if it is any good


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    Member Dean_Bean's Avatar
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    Re: Re-useable Vacuum Sealer Bags

    Jaybee,

    Sorry to go OT, but does that thing say that you can cook with those bags?

    Im experimenting with sous vide (low temp water bath) at home and this looks like a nice cheap way to have a crack...

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    Bean Powered Member jaybee's Avatar
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    Re: Re-useable Vacuum Sealer Bags

    What a top idea. Just need something to keep water at 60 degrees.

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    Bean Powered Member jaybee's Avatar
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    Re: Re-useable Vacuum Sealer Bags

    A quick Google suggests that a rice cooker on warm mode could work...

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    Sleep is overrated Thundergod's Avatar
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    Re: Re-useable Vacuum Sealer Bags

    Quote Originally Posted by 3A3129323535500 link=1294655662/0#0 date=1294655662
    The bags are resealable
    Doesnt look like youre lining them with freezer bags to keep them clean.

    Quote Originally Posted by 3A3129323535500 link=1294655662/0#0 date=1294655662
    The vacuum can be drawn to any pressure – if you are worried about having an outer-space like vacuum and losing those vital oils, worry no further.
    Id still worry.




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    Bean Powered Member jaybee's Avatar
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    Re: Re-useable Vacuum Sealer Bags

    Quote Originally Posted by 5B677A616B6A7D68606B0F0 link=1294655662/4#4 date=1294708488
    Doesnt look like youre lining them with freezer bags to keep them clean.
    Im not, but that us a very good idea, thanks!

    Quote Originally Posted by 5B677A616B6A7D68606B0F0 link=1294655662/4#4 date=1294708488
    Id still worry.
    Ive read the physics, and there is certainly cause for some concern. In mitigation, it isnt a true vacuum in the lager sense as it is a soft bag crushed by outside air. The chamber required to provide the diferential to cause offgassing is small (ie the space between beans) and it is the reason why the water in steak does not boil off when packed - it is still under normal pressure from the outside.

    But because beans are solid semi-regular oblate spheroids (ish!), there are those gaps and thay can make difference. So Heres the deal. I have packed two bags each with 40g of fresh Merlo Private blend which will equate to 4 shots of coffee each. One I have gently expelled the air out of and sealed, the other I have given the maximum vacuum possible with that little gizmo. It is not too bad - the pack is rock hard (and I would never ever try and store beans like that normally).

    I am going to leave both packs in a dark cupboard for a month and blind taste test them against fresh Merlo. I have to say that my palate isnt brilliant, so if there is a Brisbane get together in the next few weeks, Ill get an expert to do it!

    I have absoulutely no idea what will happen, so that makes it fun!

    Quote Originally Posted by 4B6A6E61504D6A6E610F0 link=1294655662/1#1 date=1294699702
    Sorry to go OT, but does that thing say that you can cook with those bags?
    it says the bags can goto 60C for defrosting, so should be ok


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    Re: Re-useable Vacuum Sealer Bags

    Do you know the roast date of that coffee? Difficult to do an accurate test without that info...

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    Bean Powered Member jaybee's Avatar
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    Re: Re-useable Vacuum Sealer Bags

    Thats an easy one - BarMerlo sells fresh every day and I got that batch on the 7th. That should be sufficient to know how old the beans are. (I can tell anyway - Ive been enjoying their coffee for the last few years)

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    Re: Re-useable Vacuum Sealer Bags

    Fresh?
    Are you saying that they are sold on the same day they are roasted?
    How do you know this?

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    Bean Powered Member jaybee's Avatar
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    Re: Re-useable Vacuum Sealer Bags

    Nope, Im saying that they deliver fresh beans every day to use. Their website says that they roast every day. I assume that the beans are rested for a suitable period before they are delivered.

    If you were to order from their on-line store, you would get the packs date stamped with the rost date, but that doesnt happen in store as they use the same batch of beans that are being used in the store at that time. (That isnt always true for coffee shops and carts that use Merlo coffee. Get your beans from BarMerlo or their website for max freshness and the lovely Private Blend - also I have no affiliation to said organisation, I just love their beans!)

    IIRC Campos operate this way too.

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    Re: Re-useable Vacuum Sealer Bags

    Well, without roast dates you might still get an interesting side by side comparison.

    No need to recommend where I should buy beans, I wouldnt buy beans from a store that leaves their dosers full (why bother with fresh if its stale for use in coffee) and would be hesitant to put my money into a company that seems to have sourced a great deal of kopi luwak... (no mention of cage-free that I could see). Unfortunately merlo fills both requirements.

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    Bean Powered Member jaybee's Avatar
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    Re: Re-useable Vacuum Sealer Bags

    Well I can guarantee that the two samples I took yesterday are from the same batch, and that the espresso that poured two hours ago from said batch tasted fresh and lovely.

    On the ballance of probabilities the batch I buy in a few weeks time will be fresher on that day, unless they use the beans from their hoppers which are stale and soiled by cat droppings ;D

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    Sleep is overrated Thundergod's Avatar
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    Re: Re-useable Vacuum Sealer Bags

    Quote Originally Posted by 2229312A2D2D480 link=1294655662/11#11 date=1294751473
    Well I can guarantee that the two samples I took yesterday are from the same batch
    Im more interested in this comparison anyway.

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    Bean Powered Member jaybee's Avatar
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    Re: Re-useable Vacuum Sealer Bags

    Drum Roll.....

    Tonight I did the test three weeks on. A fresh batch of Merlo Private blend procured this morning and the grinder left on my standard setting.

    In order of appearence: Fresh, 3 week old non vacuum, 3 week old vacuum packed.

    The older beans were noticably more oily than the fresh.

    The photos say it all.

    The fresh coffee was a dream to pour. Rich and dark and just about as good as I can get a coffee with my equipment.

    The non vacuum packed beans poured through offering little resistance. pale weak crema and quite tastless - stale rubbish.

    The Vaccum packed beans behaved exactly the same - absolutely rubbush. I did detect a smidge more residual flavour, but certainly not enough to make even a passable drink for anything but the nastiest of cafes!

    The moral of this story is buy fresh.

    I am going to re-try the experiment this time next week to see if I can pick up a difference after 7 days. 3 weeks was just too much.








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    Re: Re-useable Vacuum Sealer Bags

    Just wondering, where did you leave the beans during the period?
    Were they fully exposed to sunlight the whole time?

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    Bean Powered Member jaybee's Avatar
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    Re: Re-useable Vacuum Sealer Bags

    Never in sunlight. Shut away in the dark at room temp (24C)

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    Bean Powered Member jaybee's Avatar
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    Re: Re-useable Vacuum Sealer Bags

    So my last experiment was held tonight. I didnt bother with fresh beans, I am still using last weeks batch.

    The first pour is with 10 day old beans, stored in the normal packaging in the fridge as just I have been doing for ever. The beans are becoming stale but still providing a good shot with plenty of crema and still a nice flavour without too much bitterness coming through.

    The second pour is with beans stored at room temp in a light vacuum, in the dark. These beans are well on the way to being stale. Bitterness is quite noticable, colour is pale and crema weak. Not good.

    The third were held at high vacuum at room temp and in the dark. These beans were stale. The coffee bitter the pour quick and crema light. Undrinkable.

    I would conclude that a high vacuum does nothing but harm to your beans.

    I would also conclude that whilst a minor vacuum or airtight container does help, the best thing you can do is stick them in the fridge when not in use!

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    Re: Re-useable Vacuum Sealer Bags

    Interesting comparisons!
    Just the one drink for each?
    Im surprised that you had such bad results with 10 day old coffee. Thats usually still pretty good for espresso...

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    Bean Powered Member jaybee's Avatar
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    Re: Re-useable Vacuum Sealer Bags

    My technique is pretty consistent now - hence only one drink each. That and its a waste of good coffee!

    I was quite surprised too. Temp plays the major part as far as I can see. Brisbane room temp (24 degrees) is NOT a good place for Coffee...

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    Re: Re-useable Vacuum Sealer Bags

    Quote Originally Posted by 2B2038232424410 link=1294655662/16#16 date=1297344234
    The first pour is with 10 day old beans, stored in the normal packaging in the fridge as just I have been doing for ever. The beans are becoming stale but still providing a good shot with plenty of crema and still a nice flavour without too much bitterness coming through.
    Given that you live in delightful but hot and humid Brissy, have you noticed any condensation issues with beans taken straight from the fridge and loaded into your grinder?

    I know from many years ago when we up in PNG, loading beans from the fridge straight into the grinder caused handling problems in the grinder itself, especially if we were making several coffees in a row. Basically, it just caused a mess in the grinder with damp coffee grounds sticking to everything in sight... :(

    Mal.

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    Bean Powered Member jaybee's Avatar
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    Re: Re-useable Vacuum Sealer Bags

    Quote Originally Posted by 7D50545855390 link=1294655662/19#19 date=1297408095
    I know from many years ago when we up in PNG, loading beans from the fridge straight into the grinder caused handling problems in the grinder itself, especially if we were making several coffees in a row. Basically, it just caused a mess in the grinder with damp coffee grounds sticking to everything in sight...
    The bag certainly gets damp, but the beans are ok. If it gets too humid I turn the Aircon on for a while anyway.

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    Senior Member Journeyman's Avatar
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    Old thread but you directed me to it...

    I'm wondering if the reason for at least some of the difference is the aging. You said you used the same process for them all, but as my beans age I can get excellent results still by adjusting the grind a notch finer. I think if I tried to make a coffee from beans I've been keeping for 10 days at the same grind I used when I got them I would get a quick pour and not such a nice coffee.

    Note I DO get you were testing to see if vacuum keeps them fresh, and the 2nd test answered part of that. i.e. the 3 lots were same age and the vac-packs poured differently. I'm just wondering if the vac-packs would be more usable if grind was adjusted for them.

    Also, do you remember if the vac-packs puffed out at all in the time you kept them?

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    Super Moderator Javaphile's Avatar
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    Quote Originally Posted by Journeyman View Post
    Also, do you remember if the vac-packs puffed out at all in the time you kept them?
    In my experimenting with vacuum packing the harder the vacuum the less out-gassing the beans did. By the time the FoodSaver machine I was using got to ~80% of its max vacuum there was little if any out-gassing while the beans rested. At max vacuum there was no out-gassing at all seen and the beans/bag remained a solid, rigid mass until the seal/bag was compromised.


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    Senior Member Journeyman's Avatar
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    Were they still usable Java? Did you notice any degradation in quality of beans?

    Could the vacuum have been good enough to force out-gassing of the CO2 while the machine was running?

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    Super Moderator Javaphile's Avatar
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    Quote Originally Posted by Journeyman View Post
    Were they still usable Java? Did you notice any degradation in quality of beans?
    Usable? Sure. If you consider instant or grocery stores beans good. There was a clear degradation of flavor over beans stored in one-way valve bags.

    Could the vacuum have been good enough to force out-gassing of the CO2 while the machine was running?
    As there was no out-gassing seen at the harder vacuum levels that was my assumption.

    Somewhere on here there's a post I made that linked/refereed to an internal study/report that Illy did that was used as the basis for their claim that people could not tell the difference between their vacuum packed beans over fresh roasted beans. While they did not define what they meant by 'fresh roasted' (i.e. The beans were very likely not stored and rested so as to be at peak flavor.) their results showed that the vacuum packed beans had to rest for an hour after opening and then had to be used with-in one hour after that. Outside of those parameters people could distinguish between the fresh and the vac packed beans.


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    Senior Member Journeyman's Avatar
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    I'm not sure I would use 'good' to describe a drink from Coles beans but they were certainly drinkable, and in fact more so than quite a few coffees I paid good money for from cafés. And I learned a lot, quite cheaply, by practicing with those Vittoria beans until I got a decent coffee from them.

    But I was curious as to how the lack of CO2 affected the beans. What I was wondering is whether the amount of CO2 still in the beans might affect the taste/texture/crema of the coffee. If oxidation causes staleness, could CO2 be the source or highlighter of the things we love about fresh beans? If O2 is excluded, do the beans get staler faster than if it is present?

    It's probably something to try but several times it has been mentioned that all this testing has been done, but the threads I have seen aren't exactly definitive in model, so there would appear to be a shortfall of understanding just what changes our beans and experiences.

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    Quote Originally Posted by Journeyman View Post
    But I was curious as to how the lack of CO2 affected the beans. What I was wondering is whether the amount of CO2 still in the beans might affect the taste/texture/crema of the coffee. If oxidation causes staleness, could CO2 be the source or highlighter of the things we love about fresh beans? If O2 is excluded, do the beans get staler faster than if it is present?
    More likely a case of "what else got stripped out by the vacuum?" At lower pressures boiling points get depressed so it's highly likely that some (a lot?) of the volatiles in the beans got stripped out during packaging.

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    I would think that evaporation of flavour/aroma compounds would be a significant factor. Perhaps even moreso than oxidation? Migration through a one way valve would be much slower.

    Has anyone tried storage under a low pressure (i.e close to atmospheric pressure) CO2 atmosphere?

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    Paul Bassett recommends storing beans in vacuum containers. I think a container is better than a bag because you can control how much to vac out better. The CO2 released during the grinding process and then reaction to extraction gives you that foam and volume for crema - there's obviously a lot with fresh beans, and it goes downhill pretty quickly. I will say the vacuum seems to reduce this at least marginally faster than storing in bags. You still get crema, but what would have been a 60mL pour (which after settling would go down to ~45mL) will instead come out as a 40-50mL pour. Some say the CO2 is bad for the coffee, others only the oxygen. There's more going on than just the CO2 / gas levels.

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    Bean Powered Member jaybee's Avatar
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    Quote Originally Posted by Journeyman View Post
    Old thread but you directed me to it...

    I'm wondering if the reason for at least some of the difference is the aging. You said you used the same process for them all, but as my beans age I can get excellent results still by adjusting the grind a notch finer. I think if I tried to make a coffee from beans I've been keeping for 10 days at the same grind I used when I got them I would get a quick pour and not such a nice coffee.

    Note I DO get you were testing to see if vacuum keeps them fresh, and the 2nd test answered part of that. i.e. the 3 lots were same age and the vac-packs poured differently. I'm just wondering if the vac-packs would be more usable if grind was adjusted for them.

    Also, do you remember if the vac-packs puffed out at all in the time you kept them?
    Apologies for the late reply!

    The crude test was to determine the aging characteristics, so I didn't adjust the grind. I agree that as the coffee gets older the grinding position changes, and in reality, every shot I pour I reset the grinder for the next shot if I feel it will require it (I only usually draw 2 extractions a day).

    There has never been any gas in the bags after packaging shop bought coffee, and home roasted only off-gasses a small amount for a very short time anyway and after a day the beans are inert. A common misconception is that one way valves are there because of the production of CO2, but that's not the case. Its to squeeze out air after re-sealing, which is quite important to do.

    The National Coffee Association of the USA say " It is important to keep it away from excessive air [JB: that's the oxygen part of it!], moisture, heat, and light -- in that order" and it's worth considering how to mitigate them in your own environment. Heat was certainly my biggest issue.

    The NCA also recommend freezing coffee for longer storage, but not fridges - I must ask them why!

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    Senior Member smokey's Avatar
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    So jaybee, you recommend putting your fresh roasted beans in the fridge as opposed to vacuum sealing and storing at room temp?

    Thanks for your great posts too.

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    Senior Member Yelta's Avatar
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    Quote Originally Posted by jaybee View Post
    home roasted only off-gasses a small amount for a very short time anyway and after a day the beans are inert. A common misconception is that one way valves are there because of the production of CO2, but that's not the case. Its to squeeze out air after re-sealing,
    Not sure where you found your information Jaybee, however, as every CS home roaster knows, home roasted beans will continue to degas for a few days after roasting, happens slower in cooler weather.

    Its not a misconception, one way valves are there to allow C02 to escape.
    http://www.google.com.au/url?sa=t&rc...l4ZvkrBBfSBmLg

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    Senior Member chokkidog's Avatar
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    [QUOTE=jaybee;517964There has never been any gas in the bags after packaging shop bought coffee, and home roasted only off-gasses a small amount for a very short time anyway and after a day the beans are inert. A common misconception is that one way valves are there because of the production of CO2, but that's not the case. Its to squeeze out air after re-sealing, which is quite important to do.[/QUOTE]

    I'm not convinced as to the veracity of these claims.
    "never any gas", "small amounts....very short time" and "after a day the beans are inert" . If the latter quote was true then beans would stay at the same level of freshness (Roast plus 1 day) ad infinitum and the whole package/storage debate would be a non-argument.

    Valves......if you go to a bag makers website then the release of CO2 is exactly why they have been developed.

    http://pacificbag.com/pbiarticles/Va...SheetFINAL.pdf

    How reliable they are is another argument and yes they can be used to squeeze out air but damage to the valve is possible if not likely, resulting in failure.

    Resealing the zip lock 95% and squeezing the air out that way might be more effective but face facts ..... once a sealed bag is opened for the first time the pathway to oxidation is irreversibly accelerated. Or suck it out via the valve if that appeals to you.

    Using bag sizes that are in keeping with your use rate is more effective.

    A couple of hours on the web looking for definitive answers (about CO2 volumes over time) that don't have some form of rebuttal leads me to the conclusion that a lay person such as myself should not make claims similar to yours. That would be too misleading and the internet is rife with misleading information.

    I did find this tho' which is quite long but might (should) be of interest to some...

    http://www.balas.org/BALAS_2013_proc...ts/p639212.pdf

    Ultimately, I take a more practical view to packaging coffee; pack in small bags according to use patterns.
    Even to the point where, if a cafe I supply uses less than 2kgs/day they get their coffee in 500 gm bags.

    If you're worried about fridges, freezers, bags, valves and vacuums then change your package volume or drink more coffee!

  34. #34
    Senior Member chokkidog's Avatar
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    On the same page as you Yelta! I was googling ( ;-D ) while you were writing but I am in total agreement with you!

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    Bean Powered Member jaybee's Avatar
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    Like I say every time to folk, go try it yourself!

    Put your freshly roasted beans in a vacuum bag and seal it. do the same with 1 day, 2 day and 3 day beans and come back here and tell me that the marketing man on the web is telling you the truth

    Tell me exactly how the CO2 manages to escape at the negligible pressures...

    Can't beat physics i'm afraid

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    Bean Powered Member jaybee's Avatar
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    Quote Originally Posted by smokey View Post
    So jaybee, you recommend putting your fresh roasted beans in the fridge as opposed to vacuum sealing and storing at room temp?

    Thanks for your great posts too.
    Thanks Smokey. That approach works for me in Qld - I will add, they are in zip lock bags with the air lightly squeezed out.

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    Quote Originally Posted by jaybee View Post
    Like I say every time to folk, go try it yourself!

    Put your freshly roasted beans in a vacuum bag and seal it. do the same with 1 day, 2 day and 3 day beans and come back here and tell me that the marketing man on the web is telling you the truth

    Tell me exactly how the CO2 manages to escape at the negligible pressures...

    Can't beat physics i'm afraid
    What?

    Am I missing something here, or are you suggesting that vacuum packed beans won't release CO2 into the pack because the pressure is low?

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    Senior Member Vinitasse's Avatar
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    Me thinks someone has been sipping a wee bit too much egg nog Jaybee

    Thanks for the chuckle though

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    Bean Powered Member jaybee's Avatar
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    Quote Originally Posted by Vinitasse View Post
    Me thinks someone has been sipping a wee bit too much egg nog Jaybee

    Thanks for the chuckle though
    Nothing wrong with egg nog!

    Ok, Vinitasse, I challenge you to prove me wrong. I say that 250g of freshly roasted green will not cause an appropriately sized valved bag to off-gas. Prove me wrong by EASTER, and I'll send you with love and admiration, a bottle of Eggnog. Fail, and you admit to being full of, er, CO2 yourself

    I'm a professional scientist, so I don't mind being proven wrong...
    Last edited by jaybee; 23rd December 2013 at 02:23 AM. Reason: Sorry MrJack, missread your question as a statement.
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    Senior Member Yelta's Avatar
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    How can you argue with a "professional" scientist from Queensland
    Last edited by Yelta; 23rd December 2013 at 11:09 AM.

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    Quote Originally Posted by Yelta View Post
    How can you argue with a "professional" scientist from Queensland
    Try speaking slowly.

    Quote Originally Posted by jaybee View Post
    Nothing wrong with egg nog!

    Ok, Vinitasse, I challenge you to prove me wrong. I say that 250g of freshly roasted green will not cause an appropriately sized valved bag to off-gas. Prove me wrong by EASTER, and I'll send you with love and admiration, a bottle of Eggnog. Fail, and you admit to being full of, er, CO2 yourself

    I'm a professional scientist, so I don't mind being proven wrong...
    Would you mind clarifying what you are talking about? I cant quite work out if you are saying that beans in a vacuum bag won't release CO2, or that no CO2 will pass through the valve on a valve bag?

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    Bean Powered Member jaybee's Avatar
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    Quote Originally Posted by Yelta View Post
    How can you argue with a "professional" scientist from Queensland
    You could start by trying to be a little more 'Sheldon" and a lot less 'Penny'...

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    Bean Powered Member jaybee's Avatar
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    Quote Originally Posted by MrJack View Post
    Try speaking slowly.


    Would you mind clarifying what you are talking about? I cant quite work out if you are saying that beans in a vacuum bag won't release CO2, or that no CO2 will pass through the valve on a valve bag?
    The latter. CO2 is produced in small quantities directly after roasting and in trace quantities thereafter. Not enough to activate the valve in my experience. The valve is damn handy for squeezing out the remaining air though!

  44. #44
    TC
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    Thanks for the laugh guys.... Yee gads- some "interesting" stuff here.

    As a professional professional (with a Science degree), I think I need to go back to Year 9 Science to recalibrate....
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    I had a bag of beans from my local roaster - he said 4 days old when I got them. About a week later when the subject came up I went and checked them (they're kept in behind my coffee jars) and the bag was bulging with gas - wasn't enough obviously to trigger the valve and when I squashed it down to the beans, the bag did not get any more inflation.

    I take that to mean the beans will out-gas anything up to a week after roast but after 10 days it's done. Both figures could be adjusted downwards as i didn't check them except going into the cupboard (day 4) and when I squashed them (day 10 or 11)
    Last edited by Journeyman; 23rd December 2013 at 03:07 PM. Reason: Smelling pistakes

  46. #46
    Senior Member chokkidog's Avatar
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    Crikey! All the lay experts are coming outta the wood work! Must be the silly season. ;-D

    A kilo of beans will degas approximately 10 litres of CO2 ( Illy, Espresso Coffee and B.A. Blakistone, Principles and Applications of Modified Atmosphere Packaging of Foods)
    over a period of several weeks with about 40% of the volume degassing in the first 24-48 hrs (dependent on ambient temp).

    If carbon has a molecular weight of 44.01 and the gas has a density of 1.977 kg/m3 @ 1 atm and 0°C ( Wikipedia)
    perhaps one of the Sheldon types ( I'm all for Penny) can tell us how much 10 litres weigh @ 1 atm and 25°C?( Just out of interest as carbon footprints are measured in tonnes of CO2)

    Why do people say that because the bag is puffed up the valve isn't working? Have any of you packed the same roast in a valved and a valveless bag and
    compared the difference? Perhaps the Sheldon types could be a lot more scientific? Although bags don't explode, seams of unvalved bags have been known to give.

    After being around fermenting grapes for quite a few years I am very familiar with the sensation of being in a CO2 rich environment.
    The same environmental sensation can be had (at a much reduced level) if you chuck 20 kgs of roasted coffee, stored in valved bags, in your car and drive around for a while.
    CO2 is clearly emitting from the coffee and is easily distinguished from methane. :-D


    I am certainly not against vacuum packing coffee either green or roasted but I am fond of accurate information.

    I also meant to add that if the emission of CO2 relates to the degradation and oxidisation of roasted beans i.e. the process of going stale,
    then it stands to reason that for as long as the beans are going stale they will continue to emit CO2. It's just plain logic.

    Coffee beans wouldn't become 'inert" ( if they ever do ) until this process has run it's course.

    Said my bit, over and out.

  47. #47
    Sleep is overrated Thundergod's Avatar
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    I'll repeat here an experience I've posted before.

    I've only had one bag so far with a faulty valve.
    When I went to retrieve the beans from the cupboard a week after roasting, the bag had puffed up enough to pop the ziplock and the bag was as taught as could be.

    The beans did not taste one week old. I surmised they'd not aged normally because the gas had nowhere to go.

  48. #48
    Senior Member Yelta's Avatar
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    Quote Originally Posted by Thundergod View Post

    I've only had one bag so far with a faulty valve.
    When I went to retrieve the beans from the cupboard a week after roasting, the bag had puffed up enough to pop the ziplock and the bag was as taught as could be.

    The beans did not taste one week old. I surmised they'd not aged normally because the gas had nowhere to go.
    Have wondered about this as a longer term storage option for roasted beans, eliminate air and replace with CO2, wonder if anyone has done any work in this area?
    chokkidog likes this.

  49. #49
    Senior Member Vinitasse's Avatar
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    Quote Originally Posted by jaybee View Post
    Nothing wrong with egg nog!

    Ok, Vinitasse, I challenge you to prove me wrong. I say that 250g of freshly roasted green will not cause an appropriately sized valved bag to off-gas. Prove me wrong by EASTER, and I'll send you with love and admiration, a bottle of Eggnog. Fail, and you admit to being full of, er, CO2 yourself

    I'm a professional scientist, so I don't mind being proven wrong...
    I accept your challenge.

    Last night I was so annoyed by the obtuse assertions flying in the face of reality, as known by actual commercial roasters, that I decided to provide photographic evidence to prove you wrong. Knowing that scientists, even those from Queensland , respect observable evidence I respectfully submit the following:

    Before.jpg

    After.jpg

    The first picture shows a 250g bag of coffee that was roasted on the 18th of December. Last night, after reading all the silliness above, I used a vacuum to remove the air/CO2 from within the bag and let it rest overnight.

    The second pic shows the same bag 12 hours later and it has very obviously puffed itself up again with the CO2 still actively being degassed 5 days post roast. The volume of CO2 expelled is far greater than the "trace" elements described by Jaybee, and far beyond the immediately post-roast time frame Jaybee was spouting off about.

    As for the volume of CO2 given off being sufficient to vent through the valve, I wish I were able to invent a "smellometer" so that you could see just how strong the smell of coffee was in the room the bag of coffee was left in. The dining room was absolutely filled with the sweet, rich aroma of freshly roasted coffee and the only way that smell could have left the sealed bag was via the one-way valve.

    Before you suggest that the smell was released when I vacuumed the bag last night, the fact is that the vacuum is in my coffee roastery and the bag was brought into the house for photography after the fact.

    In any event, please PM me for my mailing address so that you can send me the promised egg nog. And please be fast about it as I would much rather have it for Christmas than for Easter.
    chokkidog, TC and Yelta like this.

  50. #50
    Senior Member Vinitasse's Avatar
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    Quote Originally Posted by jaybee View Post
    There has never been any gas in the bags after packaging shop bought coffee, and home roasted only off-gasses a small amount for a very short time anyway and after a day the beans are inert.
    I would just like to add that if your coffee really is that inert (read dead) so soon after being roasted it is time to switch the roasters you buy from and also time to relearn your home roasting techniques as you certainly are not getting the best out of your beans.
    chokkidog, TC and Yelta like this.



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