Annatto seeds come from the Achiote tree, which is native to South America. It is used in cooking to impart yellow color and also in makeup. The Achiote tree is also known as the "lipstick tree"!
Annatto yields a yellow to orange color depending on the method of infusion and the amount used. There are several ways to infuse for coloring.
Cold infusion: Add 1 to 2 teaspoons of seeds to a liquid oil and let it sit for a week or two. Strain seeds before use.
Heated infusion: Add 1 to 2 teaspoons of seeds to a liquid oil and heat very, very gently for about 2 hours. Strain seeds before use.
Lye solution: Add 1 to 2 teaspoons of annatto seeds to your lye solution (the color will appear dark orange). Strain seeds before use.
Replace the infused oil for the same oil in your soap recipe. For example, replace olive oil with infused olive oil. You don't want all of your oils to be infused as the color will be very deep and will tint your lather. Have fun experimenting with the wide range of colors you can get from this seed!
** Note - you can infuse the seeds several times. Each subsequent infusion will be lighter in color.