jpender wrote: If cost and convenience weren't an issue then flushing with an inert gas and very cold storage would probably be ideal. But short of that, what's good enough?

Consuming your coffee before it stales or throwing out anything that gets to old(cost and convenience not being an issue)?

The benefit of vacuum sealing is that it reduces the head space so whatever you're sealing and freezing loses less moisture in the process where water sublimes from the stuff of interest in order to come to equilibrium with its environment. It's all partial pressures. You could probably store it in a pressure vessel with a few atmospheres of argon or something if you really wanted to go nuts.

I'm not sold on freezing coffee. I'd imagine it'd be more useful on a dark roast where the cellular structure has already been disrupted and the oils are more susceptible to oxidation/going rancid, but I'd think light roasts would stale almost immediately upon being defrosted as the ice crystals that formed in the freezing process tear everything up, releasing the volatile compounds that make light roasts desirable. If you're below the melting point of volatile compounds, stuff won't come out, but then you probably want to grind and pull the shot while the stuff is still frozen. Since the specific heat of the relatively dry coffee isn't very high compared to the specific heat of water, it shouldn't impact shot temperature too much.

Exordium01 wrote:
I'm not sold on freezing coffee. I'd imagine it'd be more useful on a dark roast where the cellular structure has already been disrupted and the oils are more susceptible to oxidation/going rancid, but I'd think light roasts would stale almost immediately upon being defrosted as the ice crystals that formed in the freezing process tear everything up, releasing the volatile compounds that make light roasts desirable.

Having frozen greens, City, City+ & Full City Roasts for years I can tell you that this does not happen.

Exordium01 wrote:Consuming your coffee before it stales or throwing out anything that gets to old(cost and convenience not being an issue)?

Sure, but the context here is about storage.

Exordium01 wrote:The benefit of vacuum sealing is that it reduces the head space so whatever you're sealing and freezing loses less moisture in the process where water sublimes from the stuff of interest in order to come to equilibrium with its environment.

Vacuum sealing doesn't reduce the head space if you're storing your coffee in a jar. If it's in bag it does it reduce it somewhat, but vacuuming out most of the air and accompanying water vapor will increase the moisture loss. Anyway, roasted coffee deterioration increases with increasing moisture content. So what's the harm if a very tiny amount is removed from the beans in the freezer?

Exordium01 wrote:I'm not sold on freezing coffee. I'd imagine...

Try it.

Thanks for all the replies to this thread, it has been quite enlightening. I think a good compromise that will work for me is to vacuum seal coffee bags immediately if I'm not going to be using them right away and portion an open bag into individual containers, something like LWW bean cellars but cheaper, ideally with a tight fitting lid. And then store everything in the freezer, all the time. I think 50ml containers should be enough to store 15-20g of beans without leaving too much air inside?

Did a test with my chamber sealer (which claims to pull > 29" Hg, or less than .03% of an atmosphere left) a full size Mason jar (highest marked line is 24oz, but there's room above that), and 12oz of Dragonfly Yirg.

Jar + coffee + lid weighs 285.2g

After sealing, it weighs 284.7g

Which makes for .5g of air taken out of the jar.

Pressure today is 1024 mb, and .5g of air at 1024 mb takes up right about 14 fluid ounces of space.

CwD wrote:...12oz of Dragonfly Yirg.

Jar + coffee + lid weighs 285.2g

Typo?

Yes indeed.

I meant:

785.2 with air

784.7 without air