That helps a lot (not an exact science / anecdotal evidence). I know for a fact freezing the beans keeps them fresher longer, but I only assumed that vacuuming the air out and then freezing would be better.jpender wrote: Adding CO2 won't change the total amount of O2 or the partial pressure.
Great idea; - I will test full vacuum versus the weaker vacuum (comparable to the food saver vacuum devices), I'm breaking up a pound into 5 parts (1-2 shots a day), and 1 of 4 frozen bags will be full vacuum. So I will probably be able to test all seven coffees in the next month or so.
I don't know if frozen beans taste as good as the same fresh roasted beans did a couple of weeks/months later, but the frozen beans are definitely close enough to where I cannot tell the difference without methodically testing. Of course I want to optimize for the perfect shot, LOL, so if I notice a difference I will have to switch to buying those expensive little 12 ounce bags and eat shipping.
I did just buy a $600 chamber vacuum sealer, and I like it a lot (https://www.amazon.com/gp/product/B07YL ... UTF8&psc=1).
It can vacuum 6-9 16oz mason jars at the same time, and it's only 14"x15". It would've paid for itself quickly with the cost of coffee beans, but now that I've learned to cook at home (pandemic) I found so many uses it will eventually pay for itself even if I end up not using it for the beans.
The chamber vacuum sealer works differently than the disposable ones.. I can adjust the strength of the vacuum by changing the setting of how long it vacuums before the sealing cycle begins, and it also seals the thick mylar bags that the other units cannot (by adjusting the "seal" time for a longer duration).
VACUUM --- OR NOT?
I came across a discussion where there was a chorus agreeing that the strong vacuum of the chamber vacuums suck the flavor out of coffee. And the reasoning made sense. Because if coffee is offgassing, it seems like pressure instead of vacuum would keep it fresher longer (like a bottle of pop is under pressure, and a vacuum would probably suck away the fizz).
But I don't know what the relationship is between offgassing and the freshness of the coffee.. Is offgassing the coffee flavor boiling away? Or is it only a coincidence that when offgassing completes we are one step closer to stale coffee.
A strong vacuum does change boiling points, so it's conceivable that a strong vacuum could be boiling away flavor at room temperature (probably the coffee we smell). The boiling point of [car] antifreeze increases 3° for every pound of pressure. If the same is true for water, then 28HG of pressure would change the boiling point to ~125°. The thing that concerns me is the various flavor elements that make coffee probably have different boiling points; - so it's easy to imagine flavor boiling away at room temperature, and vacuuming could make it boil faster.
IN FAVOR OF VACUUM?
Fresh beans deserving of freezer storage in the first place, are still offgassing. A bag I vacuumed yesterday slightly puffed in about 10 minutes (Offgassing), so there is no more vacuum, and the air has been replaced with the CO2 Offgassing (i'm only guessing but this seems to me the best you can do without expensive equipment to add pressure and CO2 instead of a vacuum). So maybe if the coffee is fresh enough it can tolerate vacuum sealing (but not repeated cycles). I believe vacuum packing does indeed pump a little bit of flavor out of the beans (ages the beans maybe a day?), but in return stabilizes the beans for long-term storage.