What are the ingredients of beer and lager which preserve it?

Alcohol and hops are both preservatives.Homemade beer still has all the B vitamins in it which helps stop you from getting a hangover.Lower grade beers use formaldehide to break down the grain and increase production quantities.This is supposedly removed during filtering process but still can't be good for you.Some premium beers have rice or corn added,these can also cause hangovers.A B-complex multivitamin and vitamin E before drinking will help with keep that hangover away.  more