boil down vs braise

boil down

verb
  • To reduce in volume by boiling. 

  • To become reduced (to the most central elements or ingredients: to the essence, core, or implication for action). 

  • To reduce (to the most central elements or ingredients: to the essence, core, or implication for action). 

braise

verb
  • To cook in a small amount of liquid, in a covered pan, somewhere between steaming and boiling. 

noun
  • A sauce used for braising. 

  • A dish (usually meat) prepared by braising. 

  • Pagellus bogaraveo, syn. Pagellus centrodontus (sea bream) 

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