Cold Process Soap: Half and Half Method with Cows Milk 17

I’ve had many questions pop up in the last few weeks about making milk soaps, so today we are going to start a 5 post series for milk soaps using the Half and Half Method.

Preparing to add lye to water.

The Half and Half Method is actually very easy to follow. Here are the directions that we will follow in a step by step format.

1) Calculate the amount of lye and liquid needed for the oils you plan to use.

Adding lye to the water.

2) Measure all of the oils and set aside to heat gently.

3) Measure the lye and set aside.

4) Measure HALF of the needed liquid as water and set aside. Measure HALF of the needed liquid as milk and set aside. Milk should be room temperature, not frozen or heated.

Almost completely melted oils.

5) Add ALL of the lye to the water. Stir well. No crystals should remain on the bottom of your mixing vessel. When the temperature of this lye solution is within 110° F to 130° F, (cooler in the summer and warmer in the winter, cooler for large batches and warmer for small batches), add it to the oil mixture. Blend with an immersion blender until you estimate you are halfway through the mixing process. This will happen with most oils in about 1 minute. The mixture should NOT be thick or viscous. The mixture should be very fluid, like water.

Adding the lye solution to melted oils.

6) Now steadily pour the milk into the batch. Use the immersion blender to finish the blending so there is no chance of separation.

7) Add fragrance. Pour into prepared SHALLOW molds (1 inch deep or so). Milk soaps can get very hot and shallow molds help the excess heat dump into the air. This will prevent the milk sugars from interrupting the saponification reaction.

This is called the Half and Half Method, because you use half water, half milk, and add the milk half way through the blending of the batch.

Collect needed items:

Hydrogenated Soybean Oil
Coconut Oil
Olive Oil
Sodium Hydroxide
Cows Milk
Soap Spoon
Extra Large Square Tray Mold
Square Tray Mold
Immersion Blender
Time spent:
Weighing time: 8 minutes
Adding lye to water: 15 seconds, followed by 60 seconds of stirring
Heating of oils time: 3 minutes
Pouring lye solution into the fat mixture: 10 seconds
Using immersion blender to mix soap solution: 90 seconds
Adding milk to the batch: 20 seconds
Using immersion blender to completely mix milk into soap: 40 seconds
Pour into molds: 60 seconds
Allow soap to rest: 24 hours
Recipe in ounces:
40 ounces weight Hydrogenated Soybean Oil
20 ounces weight Coconut Oil
20 ounces weight Olive Oil

11.1 ounces Sodium Hydroxide
15 fluid ounces Cows Milk
15 fluid ounces Water

Tomorrow we will make a Goats Milk Soap. Later this week, we will make milk soaps with Buttermilk, Soy Milk, and Almond Milk.

Don’t forget to submit your blog or video posts to win the MMS Perfumer’s Kit. Remember, this kit is worth $280! Submissions are due by March 1st for posts during February.

Mixing the oils to halfway to trace.

Adding the milk to the batch.

Pouring the soap into the Extra Large Square Tray Mold.

Filling a Square Tray Mold.

Ready to cut the soap.

The soap is almost ready for the milk.

Using the immersion blender to mix batch completely.

The Extra Large Square Tray Mold is almost completely filled.

Soap after 24 hours.

Pile of cut soaps.

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Cold Process Soap: Half and Half Method with Cows Milk, 5.0 out of 5 based on 1 rating

About Andee

Director of Happiness. I'm a thirty-something soap snob. I've grown up with handmade soaps, and I love them! I really like making lotions, soaps, and perfumes. I adore mixing scents to come up with something new. My favorite scent is either Wicked or Cotton Candy. I tend to hoard fragrances, I even have an Earl Grey Tea from the MMS catalog. I won't tell you how old it is, but it sure is good!

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17 thoughts on “Cold Process Soap: Half and Half Method with Cows Milk

  • sincerelyemily

    Thank you for this series. Is this raw cows milk you are using in this soap? Will you be addressing the types of milks that can be used (raw milk, low fat or whole milk from the store, organic milk, goat milk, cream, etc.)? I hear the name “goats milk soap” a lot. I also like the detailed photos throughout the process. That is really helpful. Thanks again for the great information. Emily

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    • Andee Post author


      I don’t have a cow, yet. 🙂 And in my state it is illegal to sell raw milk. So, this milk is from the grocery store section. It is 1%, I think. All milks will give a different color, but the process is the same. No adjustment in the lye, and follow the same key points and temperatures. You will be fine. At the end of the week I will show you a color comparison of the milk soaps. All milks will give a different color. You can even reconstitute dry milk powder.

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  • Cynthia

    I can’t wait to see the rest of the series on milk-based soaps! Do have a question – the only molds I have are the wooden ones I’ve made, “log” style and I see you use a flat tray mold; can I still use my “log” mold or will the soap be adversly affected by this style of mold? BTW after reading a gozillion “informative” soap making sites, getting A LOT of misinformation – I have to say your web site AND your technical support staff are THE most informed of all. I can’t say thank you enough! TY TY TY 😉

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    • Andee Post author

      You can use the log style molds. Use the cooler temperatures and if you generally pour 3 inches deep, try a 2 inch pour. When we make milk soap we try to never go above 1″ deep. We do this so heat can’t build up in the mold. We want enough heat to make sure the reaction is complete, but we don’t want a run-away horse in temperature. The deeper your pour, the more likely you are to get the super hot temperatures. The more shallow you pour the soap, the less likely you are to get the volcano soap.

      When people freeze their milk, they are slowing the reaction down at the beginning to prevent this same problem. The issue with freezing, is that we also stall saponification. I can’t tell you the number of people who call and say they can’t produce soap fast enough because they don’t have space for the “curing” of their soap for 5 to 6 weeks.

      If we make soap this way, the Half and Half method, we won’t stall saponification AND we can get the soap dried out much sooner. It is a win for complete and safe soap, and a win for the production room which all equals a win for the bottom line!

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  • ThisHereIsMyUserName

    I have talked to soapers who use goat milk to make soap and they put it in the oven to gel after they’ve poured it into the molds. How can they do that if milk soap is so prone to overheating?

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    • Andee Post author

      I am not sure what they are doing. Is the oven on? Is it a “no drafts” location? Are the molds individual instead of a large mass? I don’t know. Please tell more.

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  • Quinn

    I tried to use the half and half method today with almond milk. When I mixed the lye into the half water amount, after a bit there was a white film forming on the top of the water. At first I thought that my spatula was disintegrating into the water/lye mix. Now I’m thinking that the lye started to separate out of the mix. Is this possible? I went ahead and made the batch but I’ll definitely be ph testing before touching.

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  • Tammi

    As Cynthia says above, after reading NUMEROUS websites, blogs, & watching YouTube videos, your website has succinctly answered one of my 2 questions. The other is what about adding pureed fruit and using it in this Half & Half Method?

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    • Tina

      The problem with fruit is decomposition. The fruit will rot. I suggest using a teaspoon and making the soap as normal. If all is good then make another time and add 2 teaspoons.

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  • erly

    I have made ​​a liquid cow’s milk soap .. but my soap does not last long ..
    entering the third week of my soap has begun moldy … what causes it? and I expect natural remedies from you … thank you …

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    • Tina

      This means you have too much material in the soap, fresh fruit or some thing. Send us your ingredient list and your process and we will help you get this fixed.

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  • Amalia

    wonderful soap , i aim for the same results the next time i’m making soap because the first batch i’ve made failed “undissolved lye ” ..but i need to ask : why do we need to heat the oils? should they be at a specific temp. before we add the lye?

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    • Taylor


      We need the oils to be at least warm enough for our reaction to take place. I recommend having your oils and lye solution both around 110 F.

      This way you are warm enough for saponification to occur without other issues from excess heat.


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