Archive for October, 2009

Soapmaking, A brief overview

October 28, 2009

We’re going to start with something basic: Soapmaking. This explains a bit about the chemistry of it, goes into the history, and defines some terms.

Archeologists have found evidence that a soap-like material was used before we left the caves. Fat from cooking animals combined with the wood ash from cooking, making this rudimentary soap. In Roman times, the washer women found that if they did their wash in water below the temple, the combination of wood ash and fat from animal sacrifices cleaned their clothing better with less effort. In the middle ages, soap was used mostly by the wealthy. It was a gelatinous substance, made from fats and wood ash. The hard bars we have now didn’t come about until after the industrial revolution, when sodium hydroxide was used.

Lye from wood ashes is Potassium Hydroxide (KOH). This is in the production of liquid soaps. Sodium Hydroxide (NaOH) is manufactured, and this is what hydrolyzes the oils and fats into the hard bar we know today.

Making soap isn’t that big a deal, really. Soap is chemically a salt: a precipitate of an acid (the fat) and a base (the lye). The lye is dissolved in a liquid, usually water, then added to the melted fats. The mix is stirred to “trace, ” about the consistency of pudding. Then the fragrance, if any, is added, and the soap is poured into a mold. The mixture hardens overnight, is sliced the next day, and set out to dry and continue saponifying (the reaction of the lye and fat). In 4-6 weeks, the soap is ready for use.

That is the cold process. I’ll be describing this process in the next post. We’ll go into hot process after the cold process instructions.