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Lye Table

A lye table allows you to:

verify that soap recipes are correct
easily subsistite types and quantities of fat in recipes
make your own balanced recipes
adjust amount of excess fat in recipes

Lye to Fat Ratio Table

This table is for those of you who want to get a bit more scientific in soap making, or just want to check and see if the person who created the recipe knew what they were doing. Each fat has it's own saponification value, or "SAP Value." And because of this, each fat requires a different amount of lye to convert the fat to soap.

For the soap to be made with no left over lye or fat you must have very accurate testing equipment. As the same oil from different sources will have a slightly different saponification value, we recommend you keep your soap a bit fat heavy to ensure you don't end up with lye in your finished product.

In the table below use the 0-4% excess fat columns (red) if you have accurate technical equipment to test for excess fat or lye. Use the 5-8% columns (green) to make good hand/body soap and the 9-10% columns (blue) if you want excessively fat heavy soap.

This page was written under close consultation by Tina Howard at Majestic Mountain Sage. In fact, the following table was made using her lye calculator, which will automatically calculate the amount of lye you need for a large variety of different fats.

Calculate the amount of lye you need by multiplying the amounts of each fat (including superfatting oil) in your recipe by the number intersected by the fat and your desired excess fat column. Then add the different lye amounts together.
Example: You want to calculate the amount of lye for a recipe that calls for for 16 oz. of lard as it's only fat. You want your finished soap to have 5% excess fat. Intersecting the Lard row with the 5% column, you find the number 0.132. Multiply 16 (fat wt) by 0.132 = 2.1 oz. of lye.

Animal
Fat Desired Excess Fat In Finished Soap

0% 1% 2% 3% 4% 5% 6% 7% 8% 9% 10%

Goat Fat
Lanolin
Lard
Mutton Fat
Tallow 0.138
0.075
0.139
0.138
0.140 0.137
0.074
0.137
0.137
0.139 0.136
0.073
0.136
0.136
0.138 0.134
0.073
0.135
0.134
0.136 0.133
0.072
0.133
0.133
0.135 0.131
0.071
0.132
0.131
0.133 0.130
0.070
0.130
0.130
0.132 0.129
0.070
0.129
0.129
0.131 0.127
0.069
0.128
0.127
0.129 0.126
0.068
0.126
0.126
0.128 0.125
0.067
0.125
0.125
0.126

Vegetable
Fat 0% 1% 2% 3% 4% 5% 6% 7% 8% 9% 10%

Canola Oil
Castor Oil
Coconut
Corn Oil
Cottonseed
Olive Oil
Palm Oil
Peanut Oil
Safflower
Soybean
Sunflower 0.137
0.129
0.184
0.136
0.138
0.136
0.142
0.136
0.136
0.136
0.137 0.136
0.127
0.182
0.134
0.137
0.134
0.141
0.134
0.134
0.134
0.135 0.134
0.126
0.180
0.133
0.136
0.133
0.139
0.133
0.133
0.133
0.134 0.133
0.125
0.178
0.131
0.134
0.131
0.138
0.131
0.131
0.131
0.132 0.131
0.123
0.177
0.130
0.133
0.130
0.136
0.130
0.130
0.130
0.131 0.130
0.122
0.175
0.129
0.131
0.129
0.135
0.129
0.129
0.129
0.130 0.129
0.121
0.173
0.127
0.130
0.127
0.133
0.127
0.127
0.127
0.128 0.127
0.120
0.171
0.126
0.129
0.126
0.132
0.126
0.126
0.126
0.127 0.126
0.118
0.169
0.125
0.127
0.125
0.131
0.125
0.125
0.125
0.126 0.125
0.117
0.167
0.123
0.126
0.123
0.129
0.123
0.123
0.123
0.124 0.123
0.116
0.166
0.122
0.125
0.122
0.128
0.122
0.122
0.122
0.123

Weight of water needed = Total weight of fat in recipe times 0.38

Using potasium hydroxide instead of Lye? Multiply the lye by 1.4 - Using the example
at the top of the table, 1.4 X 2.1 oz (lye used) = 2.94 oz of potasium hydroxide.

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