A beer case at a King Soopers store in Glendale, Colorado.

(Megan Verlee/CPR News)

The 500 year old Reinheitsgebot, or German Beer Purity Law of 1516, lays out how all beer in that country must be brewed. But lately, craft brewers have challenged those mandates, by bringing new flavors and styles of beer to Germany.

The same type of change is happening in countries all over the world as craft brewers challenge national ideals on what beer is and how it can be enjoyed, according to Charlie Papazian. He founded the Great American Beer Festival and is considered by some a "rock star" in the craft brewing world. Papazian also wrote "The Complete Joy of Homebrewing." He spoke with Colorado Matters host Nathan Heffel.