After much testing, we think that pure nitrogen bulbs (or larger pure nitrogen bottles) are best for an espresso martini and stout.
The high alcohol content of the cocktail can flatten the instant foam created by nitrous oxide too quickly in some cases.
Pure nitrogen takes longer to absorb into liquid than nitrous oxide but has a more reliable effect.
Once absorbed the drink will pour with a cascading head like a Guinness stout with zero effect on flavour.
Either bulb can be used in our iKegger 2.0 regulator or nitro bulb injector keg systems, it is up to your personal preference.
Neither N2 or N2O bulbs are for use with our older style mini regulator, it is only for CO2.