Soap Making for Beginners: Oils, SAP Values and How to Formulate Your First Recipe

If you’ve ever wanted to start making your own soap, you’re in the right place. Handmade soap is one of the best entry points into DIY skincare—it’s practical, customizable, and has strong potential for both hobbyists and small business owners.

In this post, I will break down the basics of soap making, explain what SAP values are (and why they matter), and give you a reference table of the 25 most common soap making oils so you can start building your own recipes with confidence.

What Is Soap Making (Cold Process Basics)?

Cold process soap is made by combining oils (fats) with lye (sodium hydroxide). This creates a chemical reaction called saponification, which turns those ingredients into soap.

Basic formula:

• Oils + Lye + Water = Soap

Each oil contributes different properties.  For example, coconut helps lather, lard helps hardness. The properties of each oil come from the fatty acid profile and based on that profile, we can know how each oil will affect our final bar of soap. For example, different oils impact each of the following:

• Hardness
• Lather (bubbles vs creaminess)
• Moisturizing qualities
• Longevity of the bar

That’s where SAP values come in.

What Is a SAP Value?

SAP (Saponification) value tells you how much lye is needed to fully convert a specific oil into soap.

Every oil has a different SAP value because each fat has a unique chemical composition.

SAP Value Chart (25 Common Soap Making Oils)

Below is a practical reference table you can bookmark or use in your own formulations.

⚠️⚠️IMPORTANT NOTE:

 Always run your final recipe through a lye calculator before making soap.

How to Build a Beginner Soap Recipe

A simple beginner-friendly formula often looks like:

• 40% Olive Oil (conditioning)
• 25% Coconut Oil (cleansing + bubbles)
• 25% Lard (hardness)
• 10% Castor Oil (lather boost)

This creates a balanced bar that:
✔ Hardens well
✔ Lathers nicely
✔ Isn’t overly drying

Calculating your own recipe:

Using our percentages listed above, here is a quick recipe from the lye calculator at TheSage.com -

This would yield a 51 ounce batch of soap and to figure the amount of lye needed, we need to decide what kind of superfat level we are looking for. The table below breaks it down by percentage of excess fat so if you want to have a 5% superfatting level, then you would need 7.17oz of lye.  If you prefer a higher percentage (8%) then you would need 6.94 oz of lye.  

Superfatting can be confusing at first because as our percentage goes up, then amount of lye needed actually decreases and this is because we want more free oil left in our bar (the superfat) so we need to reduce the amount of lye used to ensure there is extra oil left.  I find that a superfat level between 5 and 7 works great.  Less than that and you may have a bar that is too drying, but going up to 10% gives you more of a chance of free oils going rancid or a bar that is too soft.

Lye Table (NaOH)

Tools You’ll Need

Here is a quick list of some supplies that we've used and recommend for soap making.  While we may use different tools these days due to scaling up our batch size, this list will give you a great starting place.

• Digital kitchen scale (must-have)
• Stick blender
• Silicone soap molds
• Lye (sodium hydroxide)
• Infrared thermometer
  

Final Thoughts

Soap making is part science, part creativity—and once you understand SAP values, you unlock the ability to fully customize your recipes.

Whether you’re creating soap for personal use, gifts, or to sell in your Shopify store, this foundation will set you up for long-term success.

Start simple, test small batches, and keep notes—your perfect recipe comes from experimenting.