In cheese making we use a liquid annatto colorant to give cheese the bright orange/yellow. Would this work for CP soap too? Ingredients listed are: water, annatto, potassium hydroxide, castor oil. If so would it be better to add to lye or oils?
Annatto works great in soap. But I make an olive oil infusion with the whole real seeds.
Seems like your liquid annatto is a soap already (KOH + castor), probably to give it emulsifying properties. If you're going to try it, I would add it at trace or emulsification rather than to your lye or oils before mixing.