Pour Over Bloom

[Slayton]

Ok. So other than the fact that I'm roasting on a Huky (and loving it!!) I'm not so sure where or if this post fits in any of the prescribed menus on this forum as it's not so pertinent to how coffee is roasted as much as it is to roasted coffee itself.  Is it time to add a new tab to this forum so we can talk about coffee in and of itself without it having to be Huky oriented?? I don't know.  I just know that I've enjoyed and learned much here and there is much beyond just roasting.  There is, after all, the finished product, however you make it, and there is much to be asked and said about it.

And thus my query. I almost exclusively brew through either an espresso machine or via pour over.  My question is about pour over. I have found that with fresh coffee, even within a week and a half after roasting there is a very robust "bloom" when not quite boiling water is introduced to the grinds.  With just enough hot water introduced to wet the coffee (but just enough) the grinds will swell and rise.  It's beautiful.  But then I have used my own coffee which is over three weeks old and it will not do the same.  It won't bloom at all.  It gets wet but lies flat.

I haven't gotten particularly scientific about it, I haven't cupped these different coffees in any kind of standardized method but I definitely notice a difference. Those that bloom are more robust, alive, and have more depth.  Those that do not are more flat. It's coffee but without the nuances.

Does anyone here have any insight as to what is happening chemically/physically to the ground beans that might cause bloom in fresher coffee vs less fresh?  My gut says that it has to do with CO2 content left in the bean itself but. . . ??

Caveat:  I've just started a from home roasting business and while talking with a friend was told that I was being dumb business wise to not sell 5lbs to a prospective client. I asked this prospective client (who asked for 5lbs) how much coffee they might use within a week and they had no idea.  I suggested half that amount and was told by my friend (not the client) that I was being dumb.  My friend buys 3lb bags of coffee that he then puts through an espresso machine over the course of a month or more and notices no difference in taste.  I argued that roasted coffee does indeed go stale and I would rather sell smaller batches more often both to ensure his customers quality of experience as well as my brand integrity. I don't think I'm crazy in this. I could sell more initially but why?   

So anyway, back to the pour over question, or example, I ground up and made some coffee from my friend's 3lb bag today.  I don't know how long he's had it, probably no more than three weeks. There was no bloom.  It tasted bland and totally uninteresting.  Just kind of flat.  I suppose I should get a bit more scientific and do something of a blind test.

But.  . does anyone here have any real insight into what is happening when that coffee is producing such a lovely bloom?  Or why it's not when it doesn't?  Or roads to lead me to more understanding??

Thanks and happy Huky roasting!!

Ps. . . .his 3lb bag of beans is roasted to not quite french.  It's dark with some oil but not completely coated. I haven't found much difference in my own beans  in terms of bloom regardless of roast level.  Medium to French roast it all blooms the same as long as it's within about a week and half or so. 

[Daave]

My gut says that it has to do with CO2 content left in the bean itself but. . . ??

Yep, it's the beans degassing.

http://foodal.com/drinks-2/coffee/guides-coffee/what-is-bloom/

The older the bean is, the less CO2 it has left, which is why old beans don't have much bloom. The beans will be the most active during the first few days after roast, which is why people often suggest to wait a few days before brewing. I personally don't follow that advice and actually enjoy tasting the differences day to day, but that's because I mainly drink regular coffee and not espresso. I would not recommend brewing espresso right away though, since the high amount of bloom with the high pressures is not a good combination.