That's the plastic attachment you put on top of your mason jar, and then suck the air out. Remove the plastic attachment and jar lid stays on. Like in this Youtube.

Does it make sense to use it for the jar you keep in the freezer, or out of the freezer and in the fridge? Or the jar you keep out on your counter at room temperature? Will it extend the usable freshness of the beans?

The instinctive answer would be yes. But the problem I see with this is with how much air can it really suck out of a hard walls jar? It will suck the air out of a plastic bag, but does it worth it in a mason jar?

Thoughts? Experience with this?

I use it to vacuum seal the canning jars I store my greens & roasted coffee in before they go in the deep freeze. It will remove enough air to seal the canning jar lid tighter then the water processing we use when canning vegetables. I don't think you can ask for more then that.

I understand that it will be better than nothing when I put 2-3 days old fresh roasted beans into a long storage in the freezer. But freezing works well even without vacuuming.

More importantly, what about when they are out of the freezer, at room temperature. That is when most of the degradation happens. And I would like to know what kind of extended life realistically I will get if I keep vacuuming the jar every day after taking a dose out.

LaDan wrote:I understand that it will be better than nothing when I put 2-3 days old fresh roasted beans into a long storage in the freezer. But freezing works well even without vacuuming.

I don't know where you got the "better then nothing" idea? Vacuum sealing & freezing is as good as extended storage is going to get. As far as after you remove the jar from the freezer goes resealing every time you remove a dose is a waste of time IMO. Take out enough to use up within the beans optimum period & enjoy it as it ages.

I use the vacuum sealer with wide mouth jars to store green coffee, but I don't bother to vac seal roasted coffee. I bought a regular and wide mouth jar adapter but found that the regular jars don't seal well so I only use the wide mouth version.

My Wife likes to put marshmallows in a jar and pull a vacuum to watch them expand for open house at school in her science classroom.

JohnB. wrote:Vacuum sealing & freezing is as good as extended storage is going to get.

I assume this is true, but I'm wondering what your experience is with the vacuum device... are you confident that it actually gives better real world results than just filling the jars all the way? I'll consider getting one if it really makes a difference one can taste. I currently store (not optimally I know) jars for 3-4 weeks in a frost free freezer.

LaDan wrote:how much air can it really suck out of a hard walls jar?

Did a little googling (http://pump-n-seal.com/comparison.htm), and it appears that the Tilia Foodsaver can pull about 24.2" Hg - then doing the math (24.2" Hg = 0.81 atm) you would expect almost 20% of the air to still be in the jar.

I'm not a canner, but I assume the purpose of the vacuum in canning is to insure a good seal, and also to let you know if you have a failed seal - not so much to remove oxygen.

For frozen mason/ball jars, you have verification of a good seal without any vacuum shenanigans. When you take a jar out of the freezer it should be under vacuum (because of the temperature) and you will hear the lid 'ping' when it warms up if the seal is good. This is true in my experience even for beans only a day out of the roaster.

P.S.
What I sometimes do (which may be silly overkill) is to stick the nozzle of my wine preserver (inert gas) under the lid and give it a few blasts before sealing the lid and freezing. Idea is that less oxygen in there is probably a good thing. I happen to have a can of wine preserver handy on my counter, otherwise I probably wouldn't bother.

Hang on a second. Yes, we don't want oxidation, so getting the excess air out of a plastic bag seems reasonable - you're taking out the slack and limiting the remaining air that can oxidize the coffee.

But especially in a hard-sided Mason jar, there's another factor besides oxygen. Remember that we're trying to slow down the out-gassing of the carbon dioxide held within the beans. Pretty much, no CO2 = no crema, and such "dead" coffee is considered stale. Freezing, if we get the temperature down enough, can slow the carbon dioxide loss, and that's a good thing.

But we would undo the freezing benefits if a vacuum in the jar sucks CO2 out of the beans.

So, we're really looking for a technology that stores coffee under pressure - with some kind of inert gas replacing the oxygen - plus the freezing effect that slows or stops the loss of the CO2. But a vacuum in a Mason jar seems to be taking us the wrong direction.

Inert gas under pressure is the method that Illy found best for room temp storage in sealed tins. Interesting that they went with inert gas instead of CO2.

I don't think there is a problem with storing in the slight vacuum caused by freezing in mason jars - I believe they used mason jars in this experiment - Coffee: To Freeze or Not to Freeze - that got many of us on board with the idea of freezing roasted beans.

Whether using a bit more vacuum provided by the foodsaver vacuum hurts more than it helps - I guess there are factors to be considered. Sucking out CO2 as well as aromatics from the beans could offset whatever is gained by reduced O2.

There seems to be a lot of "coulds" about vacuums and related problems - I have had no issues using vacuums myself, only increased shelf life. Is there anyone willing to weigh in on negative experiences? I switched from freezing to vacuuming as I noticed flavour deterioration with my gear, for what it's worth.