Sentence:  We suppose that this author "has done his best" to be satirical; and he may have thought that his subject would have inspired him with all that was smart and "piquant": but the plain truth is that the promised <WSD>champagne</WSD> turns out to be vapid small beer. 
Meaning of the word marked with <WSD> tags:  A sparkling white wine made from a blend of grapes, especially Chardonnay and pinot, produced in Champagne, France, by the "méthode champenoise".