One of my favorite soap recipes of all time is my Buttermilk Bastile Baby Bar that you can find on a guest blog post over on I love the way this soap feels on my skin.

For more details on making goat milk soap, check out our eBook Goat Milk Soapmaking! It includes directions for full-milk soapmaking as well as the milk-in-oil method.

I received an email recently about wanting to make the soap with coconut milk instead. You can substitute the buttermilk with any milk of your choice, goat milk, almond milk, coconut milk…etc. I happened to have some powdered buttermilk on hand so decided to make a batch with that.

I also decided to add some zinc oxide. Zinc oxide is great for irritated and itchy skin.


So first of all, why do I call it bastile? Castile is soap that is traditionally made using 100% olive oil. Bastile is a term coined by soapmakers before me for soap that is almost 100% olive oil, but not quite. It typically has 10-30% other oils and butters.

The high amount of olive oil makes it a super nourishing and mild soap, perfect for baby!

Baby Buttermilk Soap

A word of warning if you make this soap, and especially if you give it as gifts: This is not a tear-free soap. The soap will burn eyes if it gets into them during the bath. Keep the soap away from baby’s eyes.

Buttermilk Bastile Baby Bar Recipe with Zinc Oxide

Olive Oil – 360 grams (75%)
Coconut Oil – 120 grams (25%)

Water – 120 grams
Lye – 66 grams
Buttermilk Powder – 1 tablespoon
Zink Oxide – 1 tablespoon

(No fragrance or essential oils in soap for baby.)

Safety Warning: This recipe is for soapmakers who have a basic knowledge of the soapmaking process and know the correct safety procedures to use when handling lye. If you are new to soapmaking, visit our beginner instructions. Be sure to wear safety goggles and gloves while soaping.

Step 1 – Make your lye solution and set aside to cool down.

Step 2 – Weigh the coconut oil into a microwave container. Melt, just until melted.

Step 3 – Add the olive oil to the melted coconut. This helps to cool the temperature down.

Olive Oil Soap

Step 4 – Add the buttermilk powder and the zinc oxide to the oils. Stir to get rid of any clumps.

soap with buttermilk

Step 5 – Once the oils and lye are cooled to under 100 degrees F, pour the lye into the oils and mix to trace.




Step 6 – Pour into your mold.


zinc oxide soap

Step 7 – Allow to sit overnight to saponify. After 24 hours unmold your soap and cure for a minimum of 6 weeks.

baby soap recipe


Happy Soaping!

Amanda Gail