For Nutate: Make your own Lye and Rendered Fat! By QillerPenguin in QillerPenguin's Diary Thu Mar 17, 2005 at 07:36:07 AM EST Tags: User Diary (all tags)
	In McGrew's story on Bad Tech, you wanted a recipe for making lye soap. Well, here's how to make the lye and render the fat, followed by a quick recipe for making lye soap:

Making Lye Lye made from wood ash is potassium hydroxide, not sodium hydroxide -- there's 10 times as much potassium as sodium in wood ash. In making soap the first ingredient required was a liquid solution of potash commonly called lye. The lye solution was obtained by placing wood ashes in a bottomless barrel set on a stone slab with a groove and a lip carved in it. The stone in turn rested on a pile of rocks. To prevent the ashes from getting in the solution a layer of straw and small sticks was placed in the barrel then the ashes were put on top. The lye was produced by slowly pouring water over the ashes until a brownish liquid oozed out the bottom of the barrel. This solution of potash lye was collected by allowing it to flow into the groove around the stone slab and drip down into a clay vessel at the lip of the groove. The hardest part was in determining if the lye was of the correct strength. In order to learn this, the soap maker floated either a potato or an egg in the lye. If the object floated with a specified amount of its surface above the lye solution, the lye was declared fit for soap making. Most of the colonists felt that lye of the correct strength would float a potato or an egg with an area the size of a ninepence (about the size of a modern quarter) above the surface. To make a weak lye stronger, the solution could either be boiled down more or the lye solution could be poured through a new batch of ashes. To make a solution weaker, water was added. Rendering Fat The cleaning of fats is called rendering and is the smelliest part of the soap making operation. Animal fat, when removed from the animals during butchering, must be rendered before soap of any satisfactory quality can be made from it. This rendering removes all meat tissues that still remain in the fat sections. Fat obtained from cattle is called tallow while fat obtained from pigs is called lard. If soap was being made from grease saved from cooking fires, it was also rendered to remove all impurities that had collected in it. The waste cooking grease being saved over a period of time without the benefits of refrigeration usually became rancid, This cleaning step was very important to make the grease sweeter. It would result in a better smelling soap. The soap made from rancid fats or grease would work just as well as soap made from sweet and clean fats but not be as pleasant to have around and use. To render, fats and waste cooking grease were placed in a large kettle and an equal amount of water was added. Then the kettle was placed over the open fire outdoors. Soap making was an outside activity. The smell from rendering the fats was too strong to wish in anyone's house. The mixture of fats and water were boiled until all the fats had melted. After a longer period of boiling to insure completion of melting the fats. The fire was stopped and into the kettle was placed another amount of water about equal to the first amount of water. The solution was allowed to cool down and left over night. By the next day the fats had solidified and floated to the top forming a layer of clean fat. All the impurities being not as light as the fat remained in water underneath the fat.  /end After that, mix one part fat and and three parts lye in a kettle with twice the water as fat, bring to a boil then reduce to a simmer. The "soap" floats to the top. Skim off, and let cool. Then put the "soap" into a clean kettle with twice the water, let boil and simmer again, and clean soap will float to the top of the water. Let cool, cut into blocks, and enjoy that clean feeling!

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