N2 is used as a commercial O2 excluding gas as it is low cost in bulk liquid quantities. This provides a dry N2 gas source and a very low temperature liquid medium for other uses. The N2 is a byproduct of the production of liquid oxygen. CO2 is also used but mostly for fire suppression as it will be released at a low temperature which causes it to tend to stay at the lower levels of the area being protected. Used as a welding cover gas to exclude O2 from the weld.

As far as CO2 + H2O -> carbonated water this is a real possibility but as the output of the coffee puck is over 150F or so there should be very little resultant dissolved CO2 if any. Drawing a vacuum on fresh pulled espresso will extract anything that will vaporize at the pressure(vacuum) and temperature at which this is performed. What that does to the taste is an interesting thought exercise.

I think N2 for packaging coffee is starting to come from RO generators. I have a small one I use for soldering in a more inert environment, useful for automated soldering with lead free solder. I wonder if I should start using it for packaging the coffee I freeze?

Ira

If you can flush with a low pressure source for 4-7 times the container volume it will work fine.

If you have access to a vacuum pump (or want to buy a cheap one: https://www.amazon.com/ZENY-Single-Stag ... acuum+pump), you can use a mason jar and this device https://www.amazon.com/FoodSaver-T03-00 ... 5M6WK0APBC to store the beans free of any oxygen. Freezing beans under a vacuum does prolong their shelf life.

aecletec wrote:Is welding gas odourless?

That I do not know, but our local welding supply company also has nitrogen that is for other purposes. It may just be filtered as was the nitrogen from the tank blanket generators at work. It may also be the tanks it is stored in that makes the difference. If I don't get deployed by Red Cross in the next day or three I will try to find an answer but it may be easily available on the internet.

There is wet pumped and dry pumped for industrial use and there should also be a medical grade which is not likely to be available at local welding shop. Dry pumped would be the better choice. CO2 is probably lower cost though.

CO2 is way cheaper and the tanks are also way cheaper.

Ira

Still using private preserve and the airscape canister. I do 3 short bursts ( old nuc recommendation) and my perception is that my coffee stays fresh longer and I get better shots overall. It has become part of my routine for espresso.