妙法蓮華經玄義 9.77

9.77

若約五味。乳唯論正。酪唯論傍。生蘇、熟蘇，傍正相兼帶。醍醐唯正。

If considered in terms of the five flavors: milk discusses only the primary; curd discusses only the secondary; raw butter and clarified butter combine and carry both the secondary and the primary; ghee is exclusively the primary.