All this salvaging and whatnot turned out a good but fairly standard porter. It was dark and had coffee flavors; bitter but not overly so. A relatively thin "mouthfeel" but more of a head than I expected given my typical experience with Summit's Great Northern Porter.
Perhaps I should try the other bottle at room temperature (though the importer's web page suggests that it be slightly chilled.)
Other reviews: http://beeradvocate.com/beer/profile/935/14563