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Soap Making Basics Part 3: How To Make Basic Cold Pressed Castile Soap

In this series, as promised, I am going to show you how to make cold pressed soap. I have made just about every type of soap you can make and cold processed is my favorite because it is unmatched in quality. As I have mentioned in previous parts of this series, there is a wait to cold process soap. You can not make it and use it right away. However, in my opinion, the amount of lather and beauty that comes from this bar of soap is worth the wait.


Without further ado, let us began soap making!

This is a very easy and very basic soap recipe. The reason I chose this recipe to share with you to begin is that it does not require much mixing, no heating, and you can do a lot with this soap recipe around the house. Have you ever wondered whether you could make your own laundry soap and dish soap? You can! A basic kitchen soap recipe will be a staple for you in the home.

Technically, you can use any bar of soap in those recipes but different oils in soaps add cost and that is why I suggest that this recipe because it is extremely cost effective. So this recipe is a Castile soap recipe. Castle soaps are made with 100 percent olive oil. Castile soaps do not have the lather and bubbly aspects of soaps made with other types of oils, but they are a pure and slippery type of soap. They are great for making your homemade home products for this reason. They do wonderfully in laundry soap and the thickness when they are shredded make a great textured hand soap. I promise, in the coming weeks, we will discuss laundry soap, hand soap and all of the things you can do with your newly made soap!

What you will need:

  • Silicon Mold or Mold of Choice

  • Distilled Water

  • Lye

  • Virgin Olive Oil

  • Essential Oil of Choice

So now that we have established what type of soap we are making and what we need to make the soap, we have to calculate amounts. I have never had any luck with recipes I have found online. They always end up lye heavy. A lye heavy soap is not good to use on your skin and I have had to repurpose a lot of soap experimenting with other people's recipes. What I do to calculate my soap is use the lye calculator from the Soap Guild. They have been the most reliable. You can always do the calculations yourself to be sure, but I have always had amazing luck with this specific calculator.

In this recipe, I use 33 oz of olive oil. To calculate how much lye we need, we need to establish if we want a lye discount and how much of a discount we want. A lye discount, or superfatting, is used for a number of reasons. One of the reasons is to ensure that your bar of soap does not end up lye heavy and is safe to use. Another reason you would want to lye discount is to make the soap a softer bar that is more gentle on your skin. A hard bar of soap has a very low lye discount. I typically use a lye discount of 2-4 %. There is a chart on the soap guide that will help you. Remember you need to measure everything as close to exact as possible to ensure the most accurate outcome.

With a lye discount of 3%, our soap recipe is as follows:

33 oz Virgin Olive Oil

4.336 oz Sodium Hydroxide (lye)

8.6 oz Distilled Water

With our recipe created we can begin!

First start by putting on your protective eyewear and gloves then start measuring your lye and water with your scale. Carefully add your lye mixture to your water in a plastic container. Next, place a thermometer in your lye mixture or use an infrared and keep an eye on it, checking every 10 minutes or so until it reaches room temperature. The water-lye mixture will become very hot. It takes almost an hour to cool down. Keep an eye on it and do not let it sit too long. Remember, this is a caustic mixture that can cause severe burns. Do not leave it where children or pets can get to it and never leave a lye mixture unattended. Now you can measure your oils.

Once the lye mixture cools to room temperature (under 100 degrees is the rule I adhere to), you can pour that into your olive oil. Use a stick blender to mix until you feel your soap mixture beginning to thicken. At this point, you will add four drops of your chosen essential oils and stir with your rubber spatula. Then pour the mixture into your mold and allow to set. You will leave your soap to set 24-48 hours and then you will carefully un-mold your soap. Be sure to handle your soap with gloves at this time. Your soap will remain caustic for the next six weeks. Do not handle it without gloves until after this time frame.

While your soap cure, in the next series, I will talk about the things you can use your soap for when you are done. This recipe should produce 12 or so bars of soap and there is a lot you can do with this soap around the house. If you have any questions about what you just learned, feel free to comment below or send me an email at I am always available to help teach because how to be more self-reliant.

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