buttermilk vs smetana

buttermilk

noun
  • Cultured buttermilk, a fermented dairy product produced from cow's milk, with a characteristically sour taste. 

  • The liquid left over after producing butter from full cream milk by the churning process, also called traditional buttermilk. 

smetana

noun
  • A form of soured cream or crème fraîche from Central and Eastern Europe. 

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