Making Mother's Milk Cold Process Soap


Erin BaldwinIn a blink of an eye, my sweet baby girl grew into a bouncing, giggling toddler. Recently, when it came time to clean out the freezer, I struggled to figure out what to do with several storage bags full of breast milk since my little one doesn't require expressed milk anymore. Throwing it out was not an option. As someone who struggled with breastfeeding starting out, every drop was like liquid gold. That’s when I stumbled across the idea of making mother’s milk soap.

When making cold process soap you can use almost any type of milk. I selected my favorite recipe from Soaping Essentials and substituted in the breast milk to replace the water ounce for ounce. In about 90 minutes I had five pounds of rich, creamy soap gently scented with DoTerra’s Serenity calming blend of essential oils.

My experience making breast milk cold process soap was extremely positive and it was great to find a way to use the excess expressed milk — especially one that can continue to benefit my little one. One recommendation I would make for those wanting to make their own batch of mother’s milk soap is to keep this batch for your family only as it may be possible to pass along any impurities, etc., that might be in milk.

Photo by Unsplash/

How to Make Breast Milk Soap

  1. I always recommend that you double-check your recipe and run it through a lye calculator to make sure everything is correct. You can find lye calculators online; I use the one from Bramble Berry.
  2. In order to keep the sugars in the milk from scorching, it needs to be very cold or even frozen before adding the lye. One trick is to measure out the amount of milk that you need ahead of time and then pop it into the freezer the night before you plan to make soap. 
  3. Now it’s time to assemble all of your ingredients, utensils, and safety gear that you’ll need.  I like to start with a clean kitchen, putting away everything that I’m not using for soaping to keep it protected, just in case. You’ll need some basic soaping equipment. All the measurements are by weight, not volume, so you will need an accurate digital kitchen scale so that you get precise measurements. You will also need some safety goggles and rubber gloves. I make my soap in large Pryex measuring bowls using an immersion blender. You can find detailed supplies list by doing a quick search online.  
  4. Prepare your mold. The options for molds are endless. I’m going to using a wooden ELF loaf mold from Brambleberry that I’ve lined with freezer paper. I like the appearance of soap from the loaf mold, but would recommend a silicon liner. The freezer paper lets moisture through to the wooden mold and can sometimes stick the soap. It also doesn’t lay very smooth especially around the ends. But right now it’s all I have, so we are going to go with it.
  5. Pull out milk. When you have all your equipment and ingredients assembled and ready to go, you should go ahead and pull out your milk. If you haven’t premeasured your milk go ahead and do that now. If you have, you are ready to add your lye.
  6. Wearing your gloves and goggles, weight out the lye. Then very slowly, sprinkle your lye into your milk. Once the lye begins to react with the milk it will quickly start to melt.  You want to stir constantly until everything is dissolved. This takes several minutes, and it’s important not to rush. A note of caution: the breast milk might turn a bright yellow and smell a little weird. That’s OK. Set aside the lye and milk mixture to cool and work on the oil portion of your recipe.
  7. In a container, combine your oils (I used coconut, olive and palm oil). In a double boiler, or microwave using short bursts to prevent scoring, melt your oils to combine. You want both your oil mixture and your lye mixture to be roughly the same temperature. I aim for around 90 - 95 degrees.
  8. Now, you want to pour your lye mixture into the oils. To help prevent splashing, gently pour your lye mixture over the bottom of your stick blender. Make sure to “burp” your blender, by giving it a gentle tap on the bottom of the pan to remove any air bubbles that might cause the mixture to splash when starting the blender. Begin stirring your oil and lye solution together alternating stirring with the motor on and then off to help prevent air bubbles and false trace.  It should take around five minutes for your soap to reach trace (when the soap mixture is thick enough to hold an outline when drizzled across the surface.).
  9. Once trace is reached, you can stir in any essential oils, colorants or add-ins. For this batch, I’m going to be using a kid-friendly essential oil blend, Serenity from DoTerra.
  10. Pour the mixture into your mold. Most of the time at this point you want to insulate your soap by placing a piece of cardboard over the mold and then wrapping it in a towel. However, when using milk the faster the soap cools the lighter the color will be. While you can go as far as refrigerating your soap to get it to cool quickly, I decided to use leave mine uncovered and room temperature. Allow it to set for around 24 hours.
  11. Unmold your soap and slice it into bars. You’ll want to allow the bars to cure in the open air for about four to six weeks.


Photo by Fotolia/joanna wnuk

12/13/2017 11:57:53 PM

Cindystroing you can quite literally swap out the water in any cold process soap with breast milk. If you have a recipe that suits the individual mom or baby then just substitute the water for her milk in the recipe. I just made 2 batches of breast milk soap and you should know that it comes to trace very fast even when the milk is frozen, which to prevent scorching it absolutely should be. My 2 batches were completely different recipes, one a face soap which was maily olive oil, and the second a general body bar. Both came to trace fast. Less than a minute. Be ready to pour.

11/14/2017 8:17:55 AM

Thank you for sharing your iideas. I am going to be making Breast milk soap for local mom's. Would you be comfortable sharing your recipe? Or did you use one for goat milk etc?

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