Help with foams

Hi there,I've been playing around with foams lately and have had trouble getting them to remain stable. ie the foam will collapse into a very unappealing liquid with 2-3 minutes of being applied to a drink.Is there a way of extending the life of the foam by altering the recipe (like more egg white/less citrus), or by adding another nitrogen charge?Thanks in advance! http://www.reddit.com/r/cocktails/comments/3f7m94/help_with_foams/