I have been buying 5 lb. bags of Red Bird Espresso beans as my go to coffee for some time. I break it down into quart Mason jars and vacuum and freeze them. The last time I did this I apparently packed the beans too soon as they developed pressure in the jars when I opened them instead of the normal vacuum. I seem to recall I packed them after a week from roast date rather than the 10 days I had done in the past.

I am about to pack a fresh bag again. When I received this bag it was pretty much just the volume of the beans. After a couple of days it has expanded a bit from what I assume is the post roast offgassing. Might it be a reasonable assumption that if I expel the gas by compressing the bag that when it no longer swells in size that this may be the ideal time to repackage and freeze? In other words, is the valve on the bag a one way device that might indicate the best time to transfer the beans to jars for the freezer? Appreciate any comments regarding my theory.

Were the jars building pressure & pushing up the lids in the freezer? If so I'd say that your freezer isn't set cold enough. If it's happening after you take them out of the freezer it's perfectly normal. If you waited until all degassing was done you'd be freezing stale beans. I typically pack & freeze my roasted coffees 4-6 days post roast if they are for espresso. Brew roasts go into the freezer after 2-3 days.

This is the first time I have had that happen with my stored jars. The freezer has a readout on temp and has not changed, which is why I was suspicious of the timing regarding putting into jars.

It really shouldn't matter as your freezer should halt or drastically slow any outgassing if it maintains a constant temp below 0*F. Any chance the power was out long enough for the freezer temp to rise & allow enough outgassing to lose the vacuum seal?

No power loss, the pennies are still atop the ice cubes.

May have just been a "one of those things" deal and the beans were an odd lot of strange genetics that had lots of CO2.

I also divide and freeze my 5# bags of Red Bird. I usually only think about hitting the sweet spot of 7-10 days of rest. So if I'm freezing into single doses in mason jars (well, really two doses so 36 grams) I try to freeze on about day 8. If I do larger bags which will go into my airscape and be used over 3-4 days I try to get closer to 7 days.

My only problems have come when I find later that I didn't get a good seal on the bag or the jar for some reason. Air gets in but even then I don't notice a great deal of difference in the end product I just suspect it wouldn't keep quite as long (they never last me more than 2 months).

So I wouldn't change what your doing.

I agree that you should consider using smaller jars. For espresso, you're talking 20+ shots in the one quart jars. I don't know about you, but in my house that would last 5-7 days, which is plenty of time for the beans to change significantly between your first and last shots. Also, a smaller volume of beans will produce a smaller volume of CO2 via de-gassing, and the lid size difference between the 16 and 32 ounce jars isn't as big. Though, as said above, you shouldn't really be having much de-gassing in your freezer. Oh, and, I freeze for espresso usually on post-roast day 4 or 5.

I do use smaller Mason jars for day to day shots that are about 1/2 full with a 17 gram dose of beans. The quart jars are used to hold larger quantities in the freezer before breaking down into the daily use jars. To divide 5 lb. immediately into the small jars would take a lot of time weighing and many jars.

I put my beans in mason jars and stick them in my chest freezer which is around -20f. Never had one pressurize until I take it out and let it warm over night. I roast my own and put them in the chill chest 24 hours post roast or there about.