Anecdotal sources suggest that a dot on beer can bottoms indicates freshness levels. They are there to tell the distributors if the beer is fresh enough to still be sold.
Beer companies go around to stores that sell their products and check to make sure there are no old or "stale" beers on the shelves anymore.
The truth is that the Nordson Ink-Dot I.D. system identifies which spray paint machine (for creating the labels) coats each beer can on a factory line system.
A dot of ink is applied on the bottom of each can as it enters a machine.
A different color of ink is used for each machine so the source of any imperfect coatings can be instantly identified and repaired or replaced, rather than shutting down the entire line of machines.
As much as we wish it could, beer doesn’t last forever. As Stone Brewing explains, "flavor- and aroma-producing oils and acids in hops deteriorate with exposure to time, air, light or warm temperatures." So, on the rare occasions when you don't drink all your beer in one sitting, you're left with a difficult question: How do you ensure your beer tastes just as good the next time you drink it?
Here are 5 rules for keeping your beer fresh & drinkable shared by Thrillist.com.