method of coloring butter
1. For the method of coloring black butter they use crushed coal.
2. For the method of coloring red butter they use Muktsi (ko ma, local dialect).
After E. Roeder and H. Wiedenfeld 2009, p. 705: "Onosma bracteatum Wall. O. bracteatum is a remedy plant in Nepal (Pohle 1990; Rajbhandari 2001) [Nep. Koma, Muktsi, Bri mog]. Distribution: Perannual herb is growing in Himalayan part of Nepal and central Nepal. Use: Red pigment obtained from roots is used to colour butter. The colouring butter serves for offering cakes. O. bracteatum contains purple-red naphthochinone pigment, consisting of shikonin derivatives. Alkaloids are unknown, but the plant is belonging to the genus Onosma and plants of this genus have toxic alkaloids."
3. For the method of coloring yellow butter they use Turmeric (Curcuma domestica).
