The Science behind making soap

Odette Handley
20 hours ago
2 min read

SAP Values in Soap Making

This may seem unnecessary but it is vital in soap making and you cannot ignore this step.

SAP values, or Saponification values, are crucial in the soap-making process as they determine the amount of lye (sodium hydroxide) needed to convert a specific type of fat or oil into soap. Understanding SAP values helps soap makers achieve the correct balance of ingredients, ensuring that the final product is safe and effective.

What is SAP Value?

The SAP value is defined as the amount of lye required to saponify one gram of fat or oil. It varies for different oils and fats, as each has a unique fatty acid profile. The SAP value is typically expressed in milligrams of KOH (potassium hydroxide) needed to saponify one gram of fat. However, when using sodium hydroxide (NaOH) for solid soap, the values are often converted accordingly.

Importance of SAP Values

Accurate Lye Calculation: Knowing the SAP value allows soap makers to calculate the precise amount of lye needed for a given amount of fat, preventing excess lye that could result in harsh soap.
Quality Control: Consistent use of SAP values helps maintain the quality and characteristics of the soap, ensuring it meets specific standards.
Customization: Understanding the SAP values of different oils enables soap makers to customize their recipes for desired qualities, such as hardness, lather, and moisturizing properties.

How to Use SAP Values in Soap Making

Identify Oils and Fats: List all the oils and fats you plan to use in your soap recipe.
Find SAP Values: Refer to a reliable source or chart that provides the SAP values for each oil.
Calculate Lye Amount: Use the SAP value to calculate the amount of lye needed for each oil based on its weight in the recipe.
Adjust for Superfatting: Consider adding a percentage of extra oils (superfatting) to ensure the soap is moisturizing and to account for any measurement inaccuracies.

Conclusion

Understanding SAP values is essential for anyone interested in soap making. By accurately calculating the lye needed for different fats and oils, soap makers can create high-quality, safe, and effective products tailored to their preferences.

Here is a great chart for SAP values

There are also calculators on the web that will work this out as well if you are worried about your Maths.