https://vinepair.com/wine-blog/33-the-many-myths-of-rolling-rock/
Theories abound, maybe as a clever marketing ploy, or maybe because when you sit around drinking cases of Rolling Rock, you tend to wonder about this kind of stuff. One theory is that the Tito brothers bought the original Latrobe brewery site in 1933 (before Prohibition was repealed, clearly a gamble worth celebrating). According to the Rolling Rock site, one theory says there were 33 steps from the brewmaster’s office to the brewery floor (less exciting, unless you’re the guy who has to count those steps every day and you maybe want future posterity to recognize your quad strength?). There’s also a theory that, since Latrobe was founded in PA—where the Groundhog is like a rodent Jesus—of course they’d acknowledge it with a 33 (Groundhog Day is the 33rd day of the year).
The 33-ness of it all doesn’t stop there. 33 degrees is the temperature at which Rolling Rock is brewed, 33 is also the number of words in the quality “pledge” on the back of every Rolling Rock bottle. And yes, 33 is the number of letters in the ingredients in the Rolling Rock itself: water, malt, rice, hops, corn, brewer’s yeast. Then there’s the 33 springs theory—since “natural spring water is a key ingredient” in Rolling Rock production (which, another theory, apparently involves 33 steps)—and there are supposedly 33 springs that feed into the brewery’s reservoir. Of course you can never have a true mystery without horse lore: legend says one of the Tito brother’s bet $33 on horse #33 at the track and used his winnings to found the brewery. And lest we forget any (semi?) secret societies, there’s some idea that the “33” is a nod to the Masons.