The biggest challenge to using milk in liquid soap is accounting for the extra fat you will be adding to your soap. Fortunately Summerbee Meadow's advanced calculator has an option for goat milk fat - but you have to know how to calculate how much fat you will be adding. For this recipe I am using 5 ounces of canned Meyenberg Goat Milk. Each ounce of this goat milk has 2 grams of fat so my 5 ounces will have 10 grams of fat. Convert that to ounces (since that is the only measurement you can use in SummerbeeMeadow's Calculator) and I will be adding .35 ounces of goat milk fat. So, when I add in the oils I am going to use into the calculator, I am also going to add .35 ounces of goat milk fat.
Since this is a more complicated method, I suggest that if you have never made liquid soap before, you start with a simple formulation to understand the process and all the stages your soap paste/paste dilution will go through before it is done. Please be sure to follow all safety precautions when making liquid soap including gloves and safety glasses. You are working with caustic materials - safety first.
This recipe is not only using goat's milk, but also both potassium and sodium hydroxides. I like to use both lyes as I feel it gives soap a bit more body. It also gives a bit more thickening when working with high olive oil content liquid soaps. I will be using the summerbeemeadow calculator as it account for the 10% impurity in KOH and adjusts for it calculating only a small excess of lye and it allow for the calculations of both lyes. I have also included just KOH amounts for those who prefer to do a single lye liquid soap. Both are calculated with a 0% superfat.
So, here we go. Since this is not a beginner formula it is assumed the the appropriate equipment and tools are already on hand. Please use all safety precautions including wearing eye and hand protection, long sleeves, long pants and closed toed shoes. Both Sodium Hydroxide and Potassium Hydroxide are caustic materials which will burn if they come into contact with your skin or eyes and can do some serious damage. Not something to scare you away, but always take appropriate safety measures when making soap from scratch.
You will need the following.
7.2 ounces Coconut Oil (76 degree)
4 ounces Olive Oil
2 ounces Castor Oil
6.8 ounces Sunflower Oil
20 ounces oil total
Dual lye (80:20):
3.36 ounces (95.25 g) Potassium Hydroxide (KOH)
.84 ounces (22.6 g) Sodium Hydroxide (NaOH)
4.62 (131 g) Potassium Hydroxide (KOH)
12.6 ounces liquid (13.8 ounces for single lye)
- 4.6 ounces distilled water (5.8 ounces for single lye)
- 3 ounces glycerin
- 5 cold goat's milk
Dilution Water - I typically start my dilution at a ratio of 1:1 between paste and boiled distilled water. Then slowly add additional boiled distilled water in smaller increments until the soap is fully diluted. Take notes so that the next time you create the same formula, you have a good idea of how much dilution water you will need. Patience is needed to allow the paste to fully dissolve into the water. I do not use a lot of heat for dilution - the warm setting of the crock pot if needed. I don't like to post an exact amount of dilution water needed because there are many factors that go into the amount you will need. These include: how much water was used up front, how much water loss during the cook, how much glycerin was used in the initial lye mixture and how concentrated one likes their finished soap to be. I find that the percentages of potassium and sodium hydroxides can also influence the amount of dilution water needed. My formulas will dilute anywhere from a 1:1 ratio to a 1:4 ratio.
Please note, this formula does not have a lye excess so there is no need to use any neutralizing agents (borax, citric acid or boric acid). All the available lye will be used to saponify the oils - no excess lye, no need to neutralize it.
Now you can omit the glycerin and use 7.6 ounces distilled water only. The added glycerin will speed up the process a bit and you may want to go a bit slower at first. Just make sure that your water amount is at least 1.1 x your combined hydroxides. This is my rule of thumb, you can play around with amounts of water and glycerin that work for your you. Summerbee Meadow will calculate your liquid at about 3 X your hydroxide weights, other calculators will compute lower amounts. The more liquid, the longer it takes to trace.
1. Measure out your chilled goat's milk and set aside.
2. Measure out your oils and heat to melt. Heat to about 160 degrees F.
3. Measure out your distilled water and lyes. Add your Potassium Hydroxide to your water to dissolve, then add your Sodium Hydroxide.
4. Once dissolved, slowly add your glycerin to the lye/water solution if using glycerin. The water/lye solution is hot enough to heat the glycerin and make it more fluid.
5. Add your lye to your oils to incorporate. You will take this mixture to trace before adding your goat's milk. You can really add your goat's milk at any point after the oils/lye mixture has homogenized and no longer separating out, but I usually wait till trace. You have to be careful though not to wait too long.
6. Stick blend you soap paste mixture as it goes through the stages of making liquid soap paste.
7. This is about the stage that I will not add the cold goat's milk.
8. You will notice that your soap paste will darken due to the addition of the goat's milk. Keep mixing until the goat's milk has incorporated into your paste. Your paste will thin out a bit since you are adding a liquid to it at this point.
9. At this point my goat's milk is incorporated and the paste is very thick and stiff. So I will start the cook. My crock pot is on low which will still cook at 160 - 180 degrees F. If I sense it is burning due to the sugars in the goat's milk, I will alternate turning it on warm, low to try to not overheat it. I will test my paste with phenolphthalein drops throughout. This soap paste will test clear with the drops within 1 - 2 hours but I continue to cook to increase the clarity.
10. After about 6 hours or so (I cook this a bit longer due to the alternating temps to keep it from burning). I have a nice dark, creamy, glossy paste. There is no hard and fast rule for cooking your paste. Some people cook for 3 hours, some cook for 9 hours.
Phenol Test - Clear, no excess lye in the paste
11. Clarity test - it is a bit cloudy, but I expect that. You can also see the sediment that is accumulating on the bottom. That is normal and will be filtered out. Milk soaps are known for creating a sludge or sediment that falls to the bottom.
12. Let the soap paste sit overnight to cool down and complete the process. This is a sample the next day. You can see the layer of sediment that has accumulated on the bottom.
13. I test the Ph of my soap and it is 9.5. I will not adjust this as it is not unusual for ph to naturally lower a bit as the soap sequesters and gets milder. Measure your ph on cooled room temperature soap for the most accurate reading. Hot soap will register a lower ph value than when it is at room temperature.
14. Dilute your remaining paste or a portion of your paste (you do not need to dilute it all at one time - whatever paste you do not dilute, place in a ziploc bag, label it and store in the fridge) using boiled distilled water. I start with a 1:1 ratio and add additional boiled distilled water as needed in smaller increments. You do not want to over dilute your soap - patience is key and everyone has their own soap concentrations preferences. Keep in mind, the more coconut oil in your formula, the less water needed to dilute, the more olive oil, more water is needed to fully dilute. The remaining steps are being shown with just a small sample of this soap.
15. Now, we do not want this sediment in our finished soap so we will filter it out with a fine mesh strainer and paper towels. Take the strainer and place it over a clean container to hold your strained soap. Place 2 - 3 layers of paper towels in the strainers.
16. Pour your liquid soap into the paper towels to strain out the sediment.
17. I did not pour all of the soap through the strainer as the sediment in the bottom was pretty heavy and this was just a small sample. This is what remained in my sample soap jar.
18. Pour your strained soap into a jar/container for sequestering. You can add your sequestering agents (glycerin for example) at this time. If you did not use enough paper towels, you can easily repeat the straining process.
19. The strained liquid goat's milk soap ready to sequester. You can see that it is not perfectly clear where you can see through it - but still looks good.
20. You soap can now sequester for as long as you like then thicken and fragrance. Goat's milk soap seems to have a natural scent that is slightly different than unscented liquid soaps not using goat's milk. That may be due to the sugars being cooked in the goat's milk. Some people really like this natural scent.
21. Here is the finished soap from diluting the full batch of paste - bottled up and ready to go. I added glycerin and water soluble shea butter at 1 ounce per pound of finished soap and thickened it with HPMC. It is scented with a combination of lavender, lime and peppermint essential oils at about 1% of the total weight of the diluted soap.