I come from a long line of soap makers. My mother made soap, my grandmother was
  considered a master soap maker and her mother and her grandmother before
  her also made soap.
 
  Since I come from a pioneer family, I am not sure how many generations
  of soap makers there have been. But there is a rich, and long history.
  But because I am a College Instructor teaching Natural Arts & Crafts, I
  have also done extensive research into the facts and fiction of soap
  making. There is much of both. I decided to make my first guide on this
  subject because there is so much mis-information surrounding the
  subject.
 
  Let me begin by saying that all soap is made using some sort of oil or
  fat and lye A.K.A. caustic ash, caustic soda, liquid potash, etc. From
  time to time you may see offers for lye-free soap. However, soap cannot
  be made without lye. There are products on the market, many of which can
  be easily located in the bath & beauty products aisles of your local
  super market, that are called Beauty Bars, or mild Bath Soap. These are
  not soap at all, but rather detergent bars. Detergent = (kerosene for
  example), which can dry the skin, causing it to feel tight, to itch and
  burn. Some people with sensitive skin may even develop a rash using such
  products. To try and offset the problem of skin irritation, many of
  these products contain lotions or creams. These additions simply attempt
  to treat the assault on the skin. They do nothing to remove the base
  problem. These products often have fragrance and color added as well.
  Many people are also adversely impacted by the scents and sometimes even
  the colorants that are included in these products.
  
   A truly natural soap can be produced today that is soothing, cleans the
  skin and will leave the skin moist. How to achieve this amazing soap is
  the point of my article. These true soaps are always made with lye and
  this article will briefly include the making of the lye.
  If the proper 3 soap making steps are carefully followed the
  resulting soap is gentle, healing, skin-softening and wonderful. It can
  be used as a shampoo, as a gentle hand laundry soap, and for an amazing
  bath soap. Lye is produced by running water through hardwood ashes. A
  favorite choice is apple wood. To test the lye for the perfect strength,
  an 1800s soap maker would float a raw egg in the solution. If the egg
  floated the lye was thought to be perfect. If it sank below the surface
  it was considered unacceptable for use in soap making.
  Once the proper lye solution was achieved, the soap maker would
  render down the fat. The favorite choice would be beef fat also known as
  tallow. This would be done by filling a large pot with 10 pounds of fat
  and placing it over a low fire. Some people would add water, others
  didn't. It was a personal choice but when no water at all was used,
  greater care was required to avoid burning the tallow. I add about one
  cup of water per 10 pounds of fat. Then I am very careful to set the
  flame very low and keep a watchful eye on the rendering for the first 4
  or 5 hours especially.
  After 12 to 24 hours of slow simmering, the fat was ready to strain.
  Usually a special cotton bag would be used. The slightly cooled contents
  of the pot would be slowly poured into the bag which would be suspended
  over a container where the liquid tallow would be collected. The bag
  would catch and hold the remaining suet. Suet would often be mixed with
  grain and allowed to harden. Suet wheels would be fed to wild birds or
  the family egg layers. Nothing was left to waste. 10 pounds of beef fat
  would yield 5 pounds of tallow. I store my tallow in a plastic shoe box
  in the fridge until I am ready to use it. For me, one batch per month
  would be enough for a year of great soap.
   I don't make my own lye. :) I used to say I didn't have a source of
  good apple wood. Now that we live in North Carolina, I will have to
  think of another excuse. Or, perhaps, I will just make  a batch of lye.
  :)
  
  Check out my additional guides on this and other subjects.