- #1
NTL2009
- 634
- 388
- TL;DR
- What contributes to ground coffee losing freshness, and what can be done about it?
Somewhat separate from the coffee advice of “buy whole beans, grind fresh at home daily”, I'm looking to understand the factors that contribute to purchased ground coffee losing freshness after opening (oxygen, humidity, temperature, time, other?). I'm assuming oxidation is the main factor, assuming normal room temperature and mid-range humidity.
It appears (I'm having trouble finding good info on this) that a high quality modern pre-ground coffee is packaged in a way that maintains 'reasonable' freshness for months(?) if unopened. I think that little button on the package was a key development - that is a one-way valve, and freshly roasted and ground coffee out gasses CO2. That valve allows for packaging fresh roasted/ground coffee (under vacuum?), and the CO2 can escape w/o blowing open the package. I think that being bathed in CO2 with very little entrapped air keeps the ground beans fresh in the package.
So my question is, how to maintain that freshness once opened? Some coffee 'experts' claim that once ground, flavor degrades in just a few days. I can't say I really notice this to any great extent (a 12 oz bag lasts me ~ one week), but I'm not doing A-B comparisons. Still, I'd like to use 'best practices' if it doesn't entail too much extra effort.
There are many suggestions out there. The most reasonable sounding to me are the piston/cylinder style containers. Put the ground coffee in the cylinder container, the lid/piston/seal is pushed down and a one way valve lets air escape, eliminating the head-space in the container. Some of these are used in conjunction with a vacuum system to remove more air. But it needs to be opened again each time you brew. This is where I need some help:
It seems that just opening and pouring the grounds into that container expose all that surface area of the grounds to air. And there is some air space between the grounds. Is that enough air, even with no head-space, to promote staling of the coffee? Is there enough air 'clinging' to the ground coffee to stale it? Or would it take a larger volume of air to stale an amount of ground coffee?
I think about this whenever I put some food into a zip-lock style bag. It is suggested to remove as much air as possible, but if it only takes a little air to stale a piece of bread, am I wasting my time trying to get most of the air out? Is only a vacuum seal really going to make a difference in practice?
I'm no chemist, but I guess I'm thinking in terms of a reaction formula. How much air, compared to the coffee, is required for the staling action?
Recently, I've just been opening a 1” slit in the bag, and I try to pour out my daily grind in more of a toothpaste tube fashion, direct from that bag. Pushing from the bottom, so very little air enters the original package, and I'm not pouring the whole package into another container, and therefore not exposing all those contents to air. I then seal the bag with a clip, and put the bag in an airtight container.
Thoughts?
It appears (I'm having trouble finding good info on this) that a high quality modern pre-ground coffee is packaged in a way that maintains 'reasonable' freshness for months(?) if unopened. I think that little button on the package was a key development - that is a one-way valve, and freshly roasted and ground coffee out gasses CO2. That valve allows for packaging fresh roasted/ground coffee (under vacuum?), and the CO2 can escape w/o blowing open the package. I think that being bathed in CO2 with very little entrapped air keeps the ground beans fresh in the package.
So my question is, how to maintain that freshness once opened? Some coffee 'experts' claim that once ground, flavor degrades in just a few days. I can't say I really notice this to any great extent (a 12 oz bag lasts me ~ one week), but I'm not doing A-B comparisons. Still, I'd like to use 'best practices' if it doesn't entail too much extra effort.
There are many suggestions out there. The most reasonable sounding to me are the piston/cylinder style containers. Put the ground coffee in the cylinder container, the lid/piston/seal is pushed down and a one way valve lets air escape, eliminating the head-space in the container. Some of these are used in conjunction with a vacuum system to remove more air. But it needs to be opened again each time you brew. This is where I need some help:
It seems that just opening and pouring the grounds into that container expose all that surface area of the grounds to air. And there is some air space between the grounds. Is that enough air, even with no head-space, to promote staling of the coffee? Is there enough air 'clinging' to the ground coffee to stale it? Or would it take a larger volume of air to stale an amount of ground coffee?
I think about this whenever I put some food into a zip-lock style bag. It is suggested to remove as much air as possible, but if it only takes a little air to stale a piece of bread, am I wasting my time trying to get most of the air out? Is only a vacuum seal really going to make a difference in practice?
I'm no chemist, but I guess I'm thinking in terms of a reaction formula. How much air, compared to the coffee, is required for the staling action?
Recently, I've just been opening a 1” slit in the bag, and I try to pour out my daily grind in more of a toothpaste tube fashion, direct from that bag. Pushing from the bottom, so very little air enters the original package, and I'm not pouring the whole package into another container, and therefore not exposing all those contents to air. I then seal the bag with a clip, and put the bag in an airtight container.
Thoughts?