cognac vs grappa

cognac

noun
  • A brandy distilled from white wine in the region around Cognac in France. 

grappa

noun
  • An Italian grape-based spirit of between 80 and 100 proof, made from the distillation of pomace. 

  • A variety or serving of grappa. 

How often have the words cognac and grappa occurred in a corpus of books? (source: Google Ngram Viewer )