Calculate Milk Amount for Soap

by Ryan
(Florida)

How do I calculate the milk amount needed for a soap recipe? I want to use goat milk in a soap at about 32% by weight.

I'm making a castile soap with olive oil and goat milk. For this question I have kept the numbers simple.

If I'm using:

100 grams "weight of oils"
100% olive oil
7% superfat

To calculate the amount of lye, I was playing around with "water:lye ratio" and found that 2.5:1 gives 31.497.

Would this be the correct way to calculate goat milk (water)at about 32% by weight, or am I over thinking this and should I be putting the 32 in lye concentration for 32%?

Answer:

'Water by Weight' refers to the percentage of water (or goat milk in your case) relative to the oils used in the recipe.

I highly recommend using the 'Water as a % of Oils' button and placing the 32% in there. It is by far the easiest way to figure out how much liquid is needed in your recipe.

The 'Lye Concentration' and 'Water: Lye Ratio' buttons are for advanced users and I think are more for those who use premixed lye solutions.

To be perfectly honest, I have never bothered to figure out how to use those buttons. Not when it is so simple to just put in the percentage I need and let the program figure it out for me.

Your playing around with the 'Water:Lye Ratio" did get you quite close to what is actually needed. By placing 32% in the 'Water as % of Oils' slot, the calculator says you will need 32 grams of liquid (which is 32% of 100) and shows the ratio to equal 2.54:1. The lye concentration equals 28.249% and the lye amount is 12.6 grams.