The Essential Brewfest Pretzel

If you're wandering the Brewfest grounds, you've simply got to try the pretzels!

Source
These are sold for each during the Brewfest event by
 * in Dun Morogh
 * in Durotar

These are special bread vendors who only show up for the Brewfest.

Note
Of the Brewfest foods, only The Essential Brewfest Pretzel counts toward the achievement. (This may be a change from previous years.)