jpender wrote: Fresh beans release enough carbon dioxide to expand a sealed bag. No question about that. It's the reason coffee is frequently sold in sealed bags with one-way valves. I've seen it the few times I've left vacuum sealed bags out at room temperature. Even bags that had been in the freezer for weeks or months still expand when allowed to warm up.

But maybe you're keeping them in the freezer? If that's the case then I wouldn't expect them to puff up at all.

Interesting...
I should pay more attention to the roast date when I seal them. Maybe they are too fresh? I do get them delivered a few days from the roast date. I think they roast and then ship which would account for the few days to arrive. So at least I know they aren't old or stale. Too fresh if anything.

I do not freeze them. They are in the cupboard. Here is a pic of a sealed bag (one of the bags from the original post a few weeks ago). It still seems very tight, no air gaps at all so i'm not sure what's going on. Not sure if I should change anything as everything is working out pretty good as is lol. I just wish I knew why these bags weren't expanding if they are supposed to?

cpro48609 wrote:I do not freeze them. They are in the cupboard. Here is a pic of a sealed bag (one of the bags from the original post a few weeks ago). It still seems very tight, no air gaps at all so i'm not sure what's going on. Not sure if I should change anything as everything is working out pretty good as is lol. I just wish I knew why these bags weren't expanding if they are supposed to?

I'm not sure what you mean by "no air gaps". Of course there are gaps in the between the beans. And using what looks in your first photo like an inexpensive vacuum sealer, you'll have significant air in those gaps.

But if after a couple of weeks the bag is "tight" then it simply means your beans were already fully degassed. From what I understand about roasted coffee that's unusual for beans just a few days post-roast.

For example, this is from a study on degassing of whole bean roasted coffee:




The amount of CO2 and the rate of degassing depends on the beans and the roasting. But after a few days (75-100 hrs) there is still a lot of CO2 that will come out between then and "a few weeks" (400-500 hrs). You'd expect something on the order of of 1mg of CO2 per gram of coffee. For a bag with 200g of coffee beans that would be on the order of 100 milliliters of gas at ambient pressure. Even if it's a fraction of that amount it would still loosen up the brick.

But you know, if it tastes good and you are happy and don't really care why it works or if something simpler would work just as well -- then there's nothing to do but enjoy it. If you care you'll need to do some experimenting.