I have tried everything I can get my hands on from Prairie (It's somehow cheaper out here for me in CA). You should try Prairie 'Merica next. It's probably my favorite regular brew that they do. I'd say the description of the beer from their website is spot on:

A baltic porter is often fermented with lager yeast, which is, not coincidentally, also what Jack's Abby uses to ferment Framinghammer. As you have noted, this information is on their website, but perhaps in much greater detail than you might have suggested.

The Kirkland beer you are referring to is contract brewed by Gordon Biersch, FYI.