café au lait vs decoction

café au lait

noun
  • A mixture of coffee and hot milk. 

  • A light coffee colour. 

  • Coffee and hot milk served in separate jugs as a breakfast drink. 

decoction

noun
  • The process of boiling something down in this way. 

  • An extraction or essence of something, obtained by boiling it down. 

How often have the words café au lait and decoction occurred in a corpus of books? (source: Google Ngram Viewer )