High Capacity Nitrogen (N2) duotight kit

Stout and nitro coffee requires high pressures (such as 2-3bar/40-60psi) so the product can push through the perforated disk that is inside our nitro spouts like this. 

These elevated pressures require Nitrogen because if CO2 was used at this high pressure the CO2 would absorb into solution and over-carbonate your beverage (if it's stored cold).  As a result Nitrogen is necessary in this application.

Nitrogen doesn't dissolve into solution like CO2.  Even at elevated pressures only very small amounts of nitrogen will dissolve into solution.  It doesn't form the weak hydrogen bond with the liquid like CO2 and for that reason it does not dissolve into water based beverages easily like CO2.