Yards: They use a packaging/bottling date that appears on all cases and bottles (found on or just underneath the should of the bottle) in typical mm/dd/yyyy format.

Yazoo: They use a Bottling date located on the label.

Yellowstone Valley: They use a bottling date which is posted on the cases boxes. From information we have seen the brewer states that it depends on where you buy it.  If it is a "shorts" bottle bought at the brewery, they probably put bottles into a re-used case box. Otherwise, format is MM/DD/YY.

Yuengling: They use a production date. Example 09001 would be Jan. 1, 2009.