Nitrogen sink or swim

[vNmd]

Was thinking of using nitrogen to evacuate air from carboys because I have a free tank. Was wondering if nitrogen will sink to the bottom of a container (heavier than air) or quickly rise out of a container (lighter than air). I have looked at the periodic table and I know nitrogen is lighter than oxygen and there is a lot of it compared to oxygen in the air, just wondering what nitrogen will do in a container? Would co2 be better? I assume co2 is heavier than air from every dry ice experiment I have ever seen it seems to drop to the floor.

 

[Hamaki]

Since air is something like78% nitrogen I suspect that the temperature of the nitrogen you introduce would have more to do with whether it tends to rise or sink than the molecular weight. Not sure how fast the nitrogen will diffuse into the headspace air but if you pressurize & purge a closed headspace several times I think you can reduce the oxygen concentration to a fairly inconsequential amount.

 

[Qhrumphf]

I would use CO2. If you want to burn nitrogen, and have the freezer space, I would go buy a whole boatload of hops by the pound, and repackage them by the ounce, or a mix of 1 oz, 2 oz, 0.5 oz, whatever you often use. Nitrogen flush and then vacuum seal.

 

[ajdelange]

If you pass a tube down to the bottom of the carboy and let the gas flow in from there it doesn't much matter which you use as the gas flowing in from the tube will push the air above it out. There will, with either gas, be a lot of intermixing because of the turbulent flow around the end of the tube. If you admit the displacing gas very slowly (no tubulence) CO2 being heavier will at first pool at the bottom of the carboy but will mix with the air above reasonably quickly by diffusion.