Vanillin has really nice vanilla flavor and has a bitter component, without sweetness.
Need to balance the vanillin by adding some sweetner and cream. Use only 1/16 tsp per big cup of coffee.
It is used as food additive and widely used in food, sweets, candy, ice cream, whipped cream, icing, cakes, drinks and cosmetics as fragrance enhancer & fixative.
*USP-United States Pharmacopeia Reference Standard