Can You Make Handmade Milk Soaps (Goat, Coconut, Buttermilk, Cow's Milk) Using the Hot Process Soap Making Method?
Can you use milk in a hot process soap recipe? I’ve been getting this question a lot from people who want to make hot process soap but who have heard they can’t use milk with this method. Some people are pretty adamant that using milk in hot process soap is not a good idea, or perhaps is not even possible.
There is some debate among hard-core soap makers about which method of soap making is best: hot process or cold process. It seems everyone has their preference depending on a number of factors. Although I’ve made some very nice cold process soaps in the beginning of my soap making experience, I have learned I really prefer hot process over cold process soap making.
Just my opinion. And it’s fine if it differs from anyone else’s out there. Soap making is both an art and a science, and once you start making your own soaps, it’s addicting! It seems like everyone eventually wants to make soaps with milk as the base, and this requires some extra skills.
One of the misconceptions I have come across several times is that you can’t use the hot process method to make handmade soaps using milk.
But I am here to tell you, hot process soap maven that I have become, is that YES! You can use milks and other dairy products in your hot process soap!
Good news, right?
It’s a slightly different process than the cold process method, and the soap turns out a little differently too. So here’s how to use milk in your hot process soaps and still get a good handmade soap product.
Why Does Milk Make Such Great Handmade Soap, Anyway?
But, maybe you’re wondering what the big deal is about milk soaps?
Well, using milk in soaps gives you an incredibly luxurious bar of soap. Generally they lather well and are highly moisturizing. The lactic acid milk contains also provides an exfoliation benefit and is great for dry and mature skin.
Milk soaps are just wonderful for people with sensitive skin, or those who want a premium soap experience. Soaps made from milk tend to be creamy, conditioning, and soothing.
Goat milk soaps, especially, are becoming more and more popular among handmade soap aficionados. However, all kinds of dairy can be used and have wonderful benefits, including cow’s milk, yogurt, coconut milk, cream, and even nut milks like almond.
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Potential Problems Using Milk in Hot Process Soap Making
Using milk requires an understanding of the soap making process. It’s a good idea to have made many soap recipes using hot process first so you have a “feel” for the whole process. This is because using milks in hot process soap recipes can be a little tricky. Some finesse is definitely needed.
Inexperience is not such a big deal with the cold process method, in my opinion. Hot process soap making is kind of the old-school traditional way (think of the pioneer women stirring huge batches of soap up over the fire using wood ash).
Because you are speeding up the saponification process through heat, there are just more things that can go wrong when you add different things in, like milks.
Another problem (really, the main one) is that milks are very sensitive to heat. This is a problem even with the cold process method of making soap because the lye solution (liquid plus lye) becomes extremely hot. This is especially true with hot process soap making, where the heat from the crock pot or other heat source can easily burn the milk.
Burned milk creates a stinky soap. Even if the soap doesn’t burn and become odorous, it is likely to caramelize, causing a brownish bar of varying shades from a pretty light brown to a darker brown.
One other possible problem you may encounter when making soaps with milk is curdling. A curdled milk soap is a real mess.
Another issue in using milk in hot process or cold process soap making is that the soap may go rancid if not done right. If you don’t have the milk, water, and lye solution just right, your soap may go rancid more quickly. This is especially problematic with high fat milks, such as buttermilk or heavy cream.
Super fatting can be affected in using some milks. If you are using regular whole milk, goats milk, etc., the fat content is around 4-6%. In this case there are no worries, and they won’t affect the superfatting of the soap. It’s when you are using high fat milks that this can be more of a problem.
Too much fat in your soap can cause your soap to actually “spoil” or become rancid.
Solutions to Problems Using Milks in Hot Process Soap Making
Some of these solutions will also apply to the cold process soap making method. But for the purposes of this article and answering the question I get so often from people about using milk in hot process soap recipes, I’m going to just discuss hot process soap.
The Solution for Inexperience:
This is pretty self-explanatory! Start off with easy non-milk recipes that have been created for and tested using the hot process method. You can find my basic hot process recipe with over 22 variations for scenting, coloring, and using herbs in this eBook: How to Make Hot Process Soap: The Ultimate Guide.
The more times you make soap, the more intuitive you will get with the process. If something goes awry, as can definitely happen from time to time, you are more able to fix the problem if you know what to look for and what to do.
And this often comes from experience.
Here’s an example: The very first time I tried to make goat milk soap using a cold process recipe and the hot process method, the cooking soap separated. It was the strangest thing! I had oils and the lye solution floating around in what looked like a curdled mess.
Well, I knew enough about the reactions of lye, water, and oils at that point to try re-emulsifying the hot mass by using my hand blender. And it happened to work! But if I had not had the hundreds of blocks of soaps behind me, I probably would have disposed of it and never tried milk in hot process soap again.
The Solution for Temperature:
When you are using milk to make handmade soap, the temperature is super important. In fact, some soap makers believe it’s everything. I happen to agree.
Milks are extremely sensitive to heat. They can burn, start smelling, and just create a mess.
The problem is that when you are using the hot process method, heat is involved. It’s unavoidable. So you have to know what things you can do to reduce the affects of the heat in the cooking of the soap.
Here are some possibilities:
1) The Temperature of Your Milk
You can freeze your milk, either to a slushy state, or even a frozen state before adding your lye. If you are completely substituting the water in a soap recipe for milk, then you really need to have it fairly solid-ish, if that makes sense. Not like an ice cube, but somewhere between slushy and ice-cube.
Then you simply add little bits of the lye to the milk. Stir. Add a little more. Stir. And keep doing this until your solution is completely mixed. Waiting a few minutes between each addition of lye helps keep the temperature cooler too.
2) When You Add Your Milk
Adding your milk later (right before mixing to trace) during the making of your soap is only a solution that’s available if you are taking the total water portion of the soap recipe and using milk as a portion of the water amount.
This won’t work if you are using ALL milk for the liquid. If milk makes up all the liquid, then you’ll have to do #1 above and be sure you’ve got a very cold, slushy, partially frozen milk.
If you are splitting up the liquid amount between water and milk, you don’t have to actually add your milk to the lye solution right up front. What I like to do when making milk soaps, especially when using high fat milks like buttermilk, is to not substitute the whole amount of milk for the water. This gives me some leeway for when I can choose to add the milk portion. This, in turn, helps me manage the temperature of the whole soap mixture.
For example, if I want to use buttermilk in a soap recipe, you can divide up the liquid (water) portion between a water amount and the milk amount.
Then, I will add equal amounts lye and water (the water amount needs to be at least equal to the lye amount) to make the lye solution. This will make an extremely strong lye solution, but no worries. You’ll be adding the rest of the liquid (milk) later.
The difference between the amount of water I use in the recipe and the total amount of water the recipe calls for is the milk portion. You only have to worry about this if you are adapting a recipe for milk.
If you are fortunate to have an already vetted hot process milk soap recipe that gives you the measurements for the water and milk, you’re golden! You can find recipes for various milk soaps in my upcoming hot process soap recipe book. I’m hoping to have it out by the end of this month, so keep an eye out!
Anyhow—-when to add the milk?
You can add the milk to the liquid oil mixture right before you pour in the strong lye solution and before bringing the mixture to trace. And if you allow the lye solution to cool down to around 90 degrees first, that’s even better.
Then go ahead and bring the mixture to trace as normal. I like to bring milk soaps to a heavy trace because I’ve found that helps with any chances of separation at the beginning of the cook time.
Here’s a specific example: If your recipe calls for 10 ounces of water for the lye solution and 4.25 ounces of lye, then you can play around with the milk amount. You could add only 4.25 ounces of water for the lye solution (equal to the lye).
Then, take the difference: 10 - 4.25 = 5.75. This measurement gives you the amount of milk you’ll add to the oil mixture later, right before you bring the soap to trace and start the cook.
3) The Amount of Milk You Use in the Recipe:
Again, this solution assumes you are taking a regular soap recipe and converting the water portion to milk or partial milk.
In the above example, I shared how you can split the liquid amount up, which will give you any where from 50% to 70% milk in your soap.
If you want to really reduce any issues in your milk soap, just adjust the water amount so that milk is only 25% of the total. Then you can add the milk as above, right before bringing it all to trace.
An example of this would be: If your recipe calls for 10 ounces of water, then you could decide that you only want 25% of the liquid to be milk (2.5 ounces), and the rest would be water. Treat the directions just like #2.
The Solution for Potential Rancidity:
If you are using a lower fat milk, like cow’s milk, nut milk etc., where the milk fat is low (around 4-6%), you don’t have to worry about this, as the final result won’t be much affected.
However, if you are using a high fat milk, this will absolutely affect the super fat percentage of your soap. Most soaps are made with a 5% to 7% super fat. This keeps the soap good for your skin, ensures there is no lye left in the soap, and helps create a very conditioning bar.
So, if you are using a high fat milk like heavy cream, for example, that is around 35% fat, then you’ll want to be sure not to super fat your soap.
With that said, I’ve used high fat milks and still kept the 5% super fat ratio in the recipe and not had a problem. However, we use our handmade soap fairly quickly or we give it away, where it gets used quickly. Thus, it doesn’t even have a chance to go rancid.
What About the Color of Milk Soaps in the Hot Process Method?
Well. This can be problematic if you are looking for that pristine bar of white soap. Honestly, it’s possible to get a very light cream color if all the hot process conditions are just right, but you are more likely to end up with a cream to light brown soap.
Personally, though, I love the color. It reminds me of caramels. In fact, when the milk cooks, that’s what happens. It caramelizes.
If you want that pure white bar of soap, you might want to try cold process, and really pay close attention to all the temperatures of the oils, the lye solution, and the milk too. Otherwise, plan to enjoy a pretty creamy to light brown soap. And if it’s darker? It’s just more variety!
The Smell of the Soap Using Milk and the Hot Process Method
The scent of your soap is so important. In my experience, different milks will give off different scents, and a little scent during the cooking process is to be expected. It may even smell a little bad.
Unless your milk is out and out burning, though, this scent is not a problem and generally goes away within a few days after the soap is finished cooking and cooling. I haven't had any issues with my milk soaps smelling bad up to this point.
So if you do get a “scent” from the soap, just give it a few days to a week and see if it doesn’t go away.
Final Reflections on Using Milk in Hot Process Soap Recipes
I love all handmade soaps, as long as they are natural (using herbs, clays, essential oils, etc. and no micas or other chemicals like fragrance oils—-BAD stuff, there). But milk soaps are in another category all together.
When you create a milk soap, you’ll feel especially skilled! At least I did, especially after hearing a few nay-sayers tell me it’s not a good idea to make milk soap using the hot process method.
My first attempt with making hot process goat milk soap was for my friend, Kelly Cable, who asked me to create goat milk soap from her recipe and write a review of her new book, Natural Soap Making for Beginners.
I explained to her that I only make hot process soap because I lack the patience to wait for the long cure time of cold process. Also, I like to know right away if my soap is going to turn out or not.
Being able to know how my soap was going to turn out was actually more of a “thing” when I was a beginning soap maker. I’ve made so many soaps at this point, I can pretty much tell during the cook exactly how it’s going to turn out at the end. Which is really nice.
Anyhow, she asked me to go ahead and give it a try and just explain what I did differently. So I did! And I’m really glad she asked me to review her book. It gave me the push I needed to go ahead and try making milk soaps using my favorite hot process method. Yay!
You can read about that recipe and what I did to change it in this article: Goats Milk & Honey Handmade Soap.
The bottom line is that, YES. You can make hot process soaps using all kinds of milks! Stay tuned for my new eBook out soon.
And if you are a beginner, please take a look at my eBook: How to Create Your Own Handmade Soap Using the Hot Process Method. You’ll learn how to make soap using this method with confidence, and you’ll have lots of recipe variations to experiment with too!
Have you made hot process soap using milk as an ingredient? I’d love you to please add comments in the comments section—-questions, experiences, anything. I’ve found this is the best way to learn, and sometimes I leave things out, or you will have an idea I didn’t think about to share!
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Hugs, Health, and Self-Reliance,
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