what do you all think of the effect of nitro-flushing on the freshness and life of coffee beans. i know for a fact that 49th parallel nitro-flushes their coffee, and I know there are others, but not sure which ones.

Basically, for those that don't know what nitro-flushing is, it's basically when the roasters bag their coffee and use nitrogen to fill the air in the bag, thus causing all the oxygen to leave, and hence preserve it's freshness and minimize/stop oxidation of the beans...so, in theory, the beans, when removed from the bag, should be like as if they were just roasted (but with less CO2 since they usually have a one-way valve installed too)

Illy nitro flushes.

Illy is very highly regarded here. The cans are very cool. The coffee, however...

There's an interesting discussion of it on coffeed: Nitrogen Flushing. One poster spoke of the benefits for coffees stored more than two weeks. If I plan to have coffee around that long, I store it in the freezer.

A few of the most highly regarded participants here did a test a few years back of storage methods (posted on alt.coffee...?), and iirc, the only method that showed any substantial preservation of the coffee and retardation of the staling process was deep freezing (a goodly amount colder than the freezer section of your refrigerator).

Once coffee is roasted the clock begins to tick. In a nitrogen atmosphere the coffee cannot, by definition at the least, oxidize. But that does not mean other process or changes in the coffee are not taking place. Once the can is opened the nitrogen is released and oxygen introduced. In my limited experience with this coffee, the coffee seems to react as if it is "thirsty" for it.

As a point of data to support that, try a can of Illy whole bean which is nitrogen packed under pressure. Many have reported that it is tasty enough when first opened. The second day, or at worst, the third, it tastes like it is weeks old. The good thing about Illy is that it comes in small cans so you can consume it before it gets really nasty.

I CO2 flushed my home-roasted (and some intelly beans, after I opened them) for a while. I think my process was pretty good, because I completely replaced the gases inside my storage bag 4-5 times. If you look at how the math works, that means less than 1% of the original atmosphere was left in the bags. Good enough for me.

I did notice less degradation of flavors over a span of about 2 weeks. While I usually no longer use beans by the 8-10th days, these still tasted like they were at 3-7 days when they were at 9-12 days. Why did i stop, then?

Well, i do mostly espresso. And oxygen-flushing (flushing out the oxygen, not in!) does nothing to stop the CO2 degassing of the beans. So while flavor was still good past 8-10 days, crema was way down. I switched over to just throwing the beans in my freezer, which slowed both staling and degassing. I've since come to realize that my freezer (about 25 degrees F or so) is not really cold enough. It will stretch the beans for a couple of days (maybe 14-21) days, but that's it.

I may go back to oxygen-flushing. I never really tested it beyond 14 days. If my process can hold beans significantly longer than that, it may be worth it for press and vacpot coffees. I also am thinking about picking up a small, super-cold freezer, if i can find one. Something on the order of 1-2 cubic feet, so it can be a counter-top appliance.

Anyone know of any advantages to Nitrogen flushing over CO2 flushing? I'm not knocking it, i just figure that either gas would be fine, since CO2 is in the beans already. Maybe your shots get more of a guiness effect with nitrogen flushing? (j/k)

Nitrogen or CO2 flushing has become an industry standard for Keurig capsules, ESE pods, and other single serving systems. The one way valves and pressurized cans have been overtaken by polymer technology, since these pods are sealed with films that allow gasses out, but not in.

Bob Yellin and I were shown around the Green Mountain plant where they do all their roasting, including a line for Keurig capsules. The ground coffee is not allowed to degas for more than an hour before it's packed in the nitrogen flushed capsules.

We tried some fresh off the line and some six month old capsules. They tasted roughly the same -- clean, generic coffee with very little aroma or distinguishing flavors.

Bottom line, the method works for C grade coffees; but Green Mountain isn't using capsules for specialty. It's progress for commodity coffee.

Illy's added twist is high pressure packaging that prevents beans from degassing. We'd need to go to Italy, where one can get the coffee fresh; but I suspect it works to get 12 to 24 hours of fresh coffee when the can is opened. The system is popular with several of the larger high end roasters (Jolly and Izzo as well as Illy) for making "hopper-canisters" that plug into the top of Mazzer grinders.

Randy G. wrote:The second day, or at worst, the third, it tastes like it is weeks old

Probably because it is!

The bottom line is that there is no downside to using nitrogen-flushed bags of coffee. Nitrogen
flushing inhibits almost all oxidation and also allows degassing to occur, which most of us find desirable. For those who prefer coffee to have degassed for several days up to a week or two, nitrogen flushing is ideal because it allows us to have our degassed coffee without loss of quality due to oxidation.

What we need is an airlock system that will dispense a dose of beans from the pressured nitrogen environment without releasing it for the rest of the beans. Or, if this is too complex, something that will re-pressurize the beans with nitrogen after you remove some from storage.