herb tea vs masala chai

herb tea

noun
  • A beverage (a tisane) made by steeping herbs (sometimes also includes other plants, such as spices), other than tea leaves, in hot water. Technically not a tea because it does not contain tea leaves. 

masala chai

noun
  • Various beverages including sweetened black tea with milk and spices. 

How often have the words herb tea and masala chai occurred in a corpus of books? (source: Google Ngram Viewer )