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The reasons why a valved bag is so important.

By Erik Olsen, 2012-03-03 08:54
de-gassing valve on bag of coffee

Two of the most common questions I am asked by customers is:

1.) How long does coffee stay fresh for?

2.) Whats the best way to store coffee to preserve freshness?

Well, freshness is entirely subjective really. What one person considers fresh, another might consider stale. Coffee doesn't go bad like Milk or Eggs. It does however get stale from oxygen, moisture and light. Oxygen being the biggest culprit. When coffee oxidizes, it gets bitter. Bitterness can also be caused by improper brewing but I'll leave that topic for another post.

Coffee starts out as a green waxy seed. The roasting process causes it to expand, change color, and give it its recognizable flavor we've all come to know and love. After the roasting process is over, the beans will give off C02 for quite a few days. A considerable amount too. My tiny 2oz sample bags used to be valve-less and they would blow up like balloons. This is where the valve plays a vital role. Since CO2 is heavier than oxygen, the “de-gassing” valve on them is used to relieve pressure but more importantly, purge out the majority of oxygen that ends up in the bag. This purging can prolong the freshness of the beans for 30-60days with minimal degradation, if unopened. Once the bag is opened, I recommend using it within 2 weeks max! Once again this is really subjective and a matter of opinion.

So whats the best way to store coffee? Never the fridge, sometimes the freezer, but really just the counter or cabinet. The problem with the fridge, is it is very humid and has so many flavors/odors, which are easily absorbed from the porous nature of roasted coffee beans. The bag would do a decent job shielding from this but its still a bad idea. The freezer can be good for long term storage but not at all for day to day use. Going from freezing temperatures to room temperature on a daily basis will cause a lot of condensation which absorbs into the coffee. You could wait for the coffee to reach room temp before opening the bag but that's not practical at all. So really the best thing you can do is squeeze out whatever air is in the bag and seal the ziplock on the top.

If you prefer a dedicated jar for your beans, rather than the foil bag. I would recommend a jar designed specifically for limiting the air space when the jar gets closer to empty. They are called airscape canisters. You can find them in different sizes and colors on Amazon
, But Ive also had local customers tell me that Healthy Living in South Burlington is carrying them.