These are how beer makers have “improved” cans, in the hopes of grabbing snobs who say the metal makes beer taste like aluminum. AdAge has the story:
Beer cans, long seen as the ugly stepchild of bottles, are making a comeback, thanks to technology that supporters say improves taste, smell and drinkability compared with old-school cans. The manufacturing advancements — which include “vented” cans and “extended lips” — are allowing cans to finally shed their reputation for tasting like aluminum.
Sam Adams plans to introduce its “Sam can” with an extended lip and hourglass ridge at the top to enhance aromatics and expel carbonation. The brewer is so confident in its technology that it's offering the design to the brewing community without asking for royalty or licensing fees. But rival craft brewers may not need a hand from Sam: In April, Pottstown, Pa.-based Sly Fox unveiled a can with a removable lid dubbed the “360 lid.”
It's too late in the day to summon any kind of outrage, so I'll just say: If the makeup of a can actually affects your beer purchase… c'mon, bro.