Adventures in soap!

Soap.  What the heck is it anyway? While today’s commercial soaps are not technically soaps at all, but detergents made from petroleum-based products, a true soap is derived from combining a fat with an alkaline substance to create “saponification”.  The question is, how in the world did our forebears think to go mixing their left-over animal fats with potash (which is what you get when you leave your ashes soaking in water)?  One of the earliest urban legends has it that the Romans discovered soap on “Mount Sapo” where  animal fat from burnt offerings dripped down onto the ashes and combined into a lathering substance that was found to be good for cleaning.  Um, gross.

While there are some historical references to home soap production in the early middle ages, it wasn’t until the 13th century that olive-oil soap factories were established in Marseilles.  However, the volatility of the saponification process made their products uneven and soap as a personal cleaning product was not widely used.  In 1775, French chemist, Nicolas Leblanc, discovered a way to manufacture soda from common salt, creating a more stable alkali (but with the drawback of a toxic byproduct).  In the 1860’s, the Belgian chemist, Ernest Solvay, improved upon Leblanc’s discovery and created Soda Solvay, thus paving the way for modern soap production.

Early American colonists made their own soap by combining animal fats rendered during cooking with lye that was created from mixing wood-stove ashes with water in an ash-hopper, a device used to render lye.

It was an imperfect science and difficult to tell the strength of the alkaline component that was being created.  One way to tell if your lye solution was strong enough to make a good soap was to float an egg in it – if you got a floater, with enough egg bobbing  above the surface, you were in luck.  Sinking objects required that the liquid be boiled down. This led to all sorts of interesting folk-wisdom regarding how to get a good batch of soap: Pay attention to the tides! Only use sassafras sticks to stir the Lye!
Perhaps we should have paid better attention to such folk wisdom when we attempted our own colonial soap making experiment with our friends upstate some time ago.  As was to be expected, our friend, Daniel, had been collecting ashes in a bucket all winter to render lye and had been saving his bacon fat, too!  We decided to make two types of soap: olive oil and bacon.  Using a colonial recipe, we were able to get the soap to “trace” – which is when the elements come together and start to turn into actual soap.  But after days, the stuff never hardened.  I wasn’t too disappointed because –  really –  was I going to use the bacon soap?

For the next several months, however,  I was vexed by my soap situation which led me to take a soap making workshop at one of  my favorite places ever: Make Workshop.  I bought all my supplies and showed up on a Friday evening in February, ready to lather up.  The workshop was given by Jeff Kurosaki & Tara Pelletier, the artists behind the groovy handmade soap company, Meow Meow Tweet, which they run out of their Brooklyn home.

They took us through the steps of cold-process soap making.  I don’t have any photos, because I was wearing gloves,  goggles and a mask.  Cold-process soap is made by mixing natural oils, lye and water.  We’ve come a long way from the folk wisdom of the  Colonial days.  Now,  to get the precise recipe you want, all you need to do is log into the Soap Calculator, a cool online device that gives you the exact measurements of the ingredients you will need for any type of soap you want to make.  For this workshop, we made two soaps: a shea butter soap and a cocoa butter soap.  The experience was like a cool chemistry class given in the art room.

The first step is to measure, combine and heat the oils, melting and mixing the solids and liquids to 110°.  You want your oils at about 100° when you add the lye, and the cooling time gives you time to mix your lye water.  Dissolving lye in water creates an exothermic reaction, and here is where things get serious. Lye is extremely caustic and one has to wear a mask and eye protection to avoid burns.  However, Jeff and Tara did their best to assure us that lye is a natural agent that, when handled correctly, is extremely useful.  Indeed, food-grade lye is used to cure a number of tasty foods (green olives and lutefisk, to name two).

Once you mix the oils with the lye water, the mixture turns cloudy and it is time to use the immersion blender.  This process is called bringing the soap to “trace”: which is when your fats and lye have successfully combined.  You can tell this is happening when it thickens and leaves little bubbles on the surface when you dribble it back into the pan.  Figuring this out is part of the art of handmade soap making.

Once your soap has successfully blended, you can start adding herbs and essential oils to give it some personality.  We used lavender in one batch and Calendula with lemon oil in the other.  Once they were mixed in, we poured the liquid into molds (paper cups, actually) and brought them home to continue the slow saponification process.  One week later, I took my new soap out of the cups, cut them into disks and washed my hands. Heaven!

Well, now I know what soap is and how to make it.  Mission accomplished.  If you’re in NYC, I highly recommend heading on down to Make Workshop to do it yourself.  However, my biggest takeaway was that until I start stocking up on lye, I’ll just buy my soap from Meow Meow Tweet!

  1. #1 by Grant on April 12, 2011 - 5:41 pm

    I like it. When I taught Chemistry at CSU, we had a lab where the students made soap. They seemed to enjoy it way more than labs that didn’t have immediate real world applications.

    I was a bit surprised, though, that you didn’t talk about how soap cleans things. They have a nice, fairly clear explanation here:

    http://chemistry.about.com/od/cleanerchemistry/a/how-soap-cleans.htm

  2. #2 by domaphile on April 12, 2011 - 8:07 pm

    You taught chemistry at CSU? Awesome. Thanks for the link! You’re right, I didn’t even thing about why we would use soap in the first place… next post! I love that you are reading this – I can always count on the old friends! xoxo

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