You'll learn over at the Home Brew Talk forum that "It takes 33 separate brews to put such flavor, such smoothness, such unvarying goodness into a single glass of BLUE RIBBON!" So it's a blend.
Interestingly it was the very same photo which was the cause of the discussion.

Great picture Alan. It presents all the strength and clarity of vision one associates with mid-20th century America (and Canada).

I think it meant blending, that each brew was the result of 33 brewings combined, to ensure consistency.

Gary

Looks like some good info in this thread: http://www.homebrewtalk.com/f14/pabst-blue-ribbon-blended-33-1-a-188354/

"33 separate brews from 33 separate kettles". Not necessarily different recipes, but I guess trying to claim that it's better to be blended (but really just averaging the bad with the "good")

Notwithstanding the somewhat compelling 'evidence' presented on HBT...33:1 is probably somehow related to those well-known modern and admittedly exotic 'triple hopped' beers.

Thirty three hops in each barrel!

Advertising was in its phase of "more = better" (did that phase ever end?) Pabst was trying to even out inconsistencies between batches so it blended them. I guess they had 33 tanks on the day that their ad agency invented the slogan.

A beer tray with the slogan:
http://trayman.net/TrayDetail/Logos/Pabst33.htm

I suspect Pabst was trying to turn a defect into an advantage. Remember Stroh's had old direct-heat boilers when all the others had steam-jacketed indirect-heat boilers. Turn the negative into a positive! So instead of "scorched beer" Stroh's called it "fire brewed"!
So, Pabst may have been trying to hide batch-to-batch variance with blending.

I doubt they would have blended unless they had to. There might have been a need to blend for another reason, say bottling, but that seems unlikely.

An old print ad with more info:

http://www.shorpy.com/images/photos/pabst.gif

I saw the same photo and was thinking of posting it. Glad you saved me the trouble. I'm a lazy man.

My knee jerk reaction was, "33 parts water, 1 part beer."

could someone call pabst and clear this up for us?

I'll grant that the 33:1 thing is marketing spin, and rather meaningless to the average beer drinker. But I'm confused as to why some folks consider any batch to batch variance a particularly unusual thing, or to consider blending to achieve consistency a bad thing. Seems to me like it would be the ideal way for any brewery (big or small) to achieve consistency in their product.
Of course, these days Pabst could probably care less about their beer...it's just a 'label' (hell...they don't even make the beer themselves anymore).

On a side note, regarding comments about Stroh's "fire brewed" beer; it's another example of marketing spin, but by the same token those direct fired kettles could hardly have been considered a negative by that company. After all, when they acquired the Schaefer brewery outside of Allentown PA back in the early 1980's, they apparently went to some trouble and expense to retrofit the plant with some direct fired kettles.

It's amazing to me to see old photos and realize that Pabst and Schlitz were some of the top brewers in America at one time... How the mighty have fallen.

Great minds think alike.

http://twitter.com/#!/adamnason/status/70950376551088129

I saw the same photo and wondered too...which brought me here. Note that the label of Rolling Rock includes a '33' ... could it have originated duringthe '30s as well? Recall that Prohibition in the US ended when beer was made legal once again, in 1933.