KOH vs NaOH

According to internet wisdom, hard soap is made with NaOH and soft soap is made with KOH.

Traditionally, home made soap was made with lye made from wood ash which yields KOH.  There is reason to believe that some of this soap was hard bar soap and some hints out there that adding salt at some point made this possible.

Almost all the info out there is on making soap with commercial NaOH but I want to make soap with home made lye.  Commercial lye is in crystalline form and all recipes are based on this form.

Home made lye from wood ash is a solution of variable but controllable concentration.  Reducing it to a crystal form is a waste of energy as water is added to all recipes to make soap.

Assuming that the two are equivalent (not quite but ignore that for now) how do I determine the amount (weight?) of the dissolved KOH in a given quantity of wood ash drippings?

I can measure the specific gravity of the solution but there is nothing in the soap literature about the specific gravity of the commercial stuff in water.

Another question....

The initial drippings from the wood ash have the same pH as when it is boiled down by a factor of 20.  Why is this?

Thanks for the help,

js
           
Astronomy, Beer, Cheese, Fiber, Gems, 
Nature, Radio, Sheep, Sausage, Silver 

      http://schmidling.com






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