is provided as is. Lye is a
dangerous substance, and though every effort has been made to
ensure that the values calculated are correct you are using this
at your own risk.
This is a lye calculator for making soap. Its
use is simple.
Simply unzip the file sap_1_1.zip
a directory on your harddrive and run saponification.exe.
- You will be presented
with a dialog box like this.
- Select the type of lye you are using: Sodium
Hydroxide or Potassium Hydroxide. Sodium Hydroxide will make solid
soap, and potassium hydroxide will make liquid soap.
- Select the unit of weight, ounces or grams.
- Next add the fat or oil you would like to use by
clicking the add button or double click in the grid.
- Select the type of oil or fat you want to add.
- Enter the amount of fat in the edit box.
- If the fat or oil you want is not listed, you can
add it by choosing custom and filling in the name and SAP value. For
Corn Oil it is a 0.136, but if you call an oil supplier that will
probably tell you 191. They are giving you the scientifically defined
sap value which is the number of milligrams of potassium hydroxide
needed to completely saponifiy 1 gram of fat (in this case corn oil).
When you enter the number and hit ok, the program will present you with
a dialog and verify the type of sap value (KOH or NaOH). Make sure you know what you are doing
when you enter in the saponification value for a fat or oil. The wrong
number can make you put too much lye in your soap and cause burns.
- If we go back and look at Corn Oil3 we can see
that the sap value was converted.
- Hit ok. If you selected a custom fat, it will be
remembered the next time you add a fat, and saved to the file sap.txt.
- Once you have your fats selected the amount of lye
needed will be shown from 0% excess fat to 10% excess fat. The X%
excess fat is the amount of fat (by percent) that is not saponified in
the process. It is good to have a little extra fat in the soap for two
reasons: 1) it ensures that all the lye is used up, and 2) it ensures
that all the lye is used up. If you have excess lye in your soap the
soap will burn you. Unless you have precision equipment for measuring
fat and lye (you don't), you should use 5% or greater. Most home soap
makers use between 5% and 8% excess fat.
- You will also see a calculation that shows you the
amount of water to use.
ALWAYS POUR LYE INTO WATER,
NEVER POUR WATER INTO LYE. Also be aware
that lye and water get really hot, so you shouldn't use a plastic
container, as it can actually get hot enough to melt through it. Some
soap makers use ice water to keep things under control.
- Lastly you will see a combined weight of all the
ingredients. This will give you a rough estimate of the final weight of
your soap, some of the water will evaporate.
- Once you are satisfied with your recipe you can
save it by pressing the save button. You will be presented with a
dialog box, and can type in the name of a new file or select an
existing file. If you select an existing file you will be prompted to
make sure that you want to overwrite it.
- To load a recipe simply click the load button, and
select the file.
Send bug reports
and comments to
There are some minor changes between Saponification 1.0 and 1.1
- There are many new oils added to the base package.
- The oils selection drop down shows you the sap value for the
fat. This allows you to have the same oil name with a range of sap
- Made the code that allows you to add custom oils a bit
smarter. It now prompts you to tell it if the sap value entered was
determined for NaOH or KOH.
- You can now save and load recipes.
- If the sap.txt file is missing, the program will create a
The sap.txt file
The file sap.txt holds all the values and can
be edited by hand, but is has a very specific format that is as
Make sure that every entry ends with a newline, and that there
are no extra spaces in the file. The sap values in the sap.txt file are
of the form the amount of Sodium Hydroxide (NaOH) it takes to convert
one ounce of fat to soap. Again
make sure you understand lye and lye calculations if you edit this file.
Many of the SAP values were obtained from the table
Obtain the latest version at http://www.gristle.to/markup/saponification.
Copyright 2003 Dudley Fox All rights reserved.
Redistribution and use in source and binary
forms, with or without modification, are permitted provided that
the following conditions are met:
Redistributions of source code must retain the
above copyright notice, this list of conditions and the following
Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
THIS SOFTWARE IS PROVIDED BY DUDLEY FOX ``AS
IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DUDLEY
FOX BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION; OR PHYSICAL INJURY)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.