Adam Engelhart

Soap: Jojoba, Crisco, and lavender

September 22nd, 2006

It was a bit late, but I wanted to get done with the soapmaking so I could start concentrating on posting this story. Only three oils remained. The first was jojoba:

Jojoba oil is weird. It’s a liquid, and not a particularly viscous one (I think this has to do with the degree of saturation), but the molecules are ridiculously long–about forty carbons each. For perspective, most oils are somewhere in the mid-teens; forty is more typical of a wax than an oil.

The saponification number is also a tiny 0.069, which stands to reason: if the molecules are so huge, then there will be fewer of them to saponify, right? Blah blah blah molar blah blah blah concentration blah blah blah molecular mass blah blah blah stochiometry. BRILLIANT! Oh, man, it is a great mystery of life why I do not have a Nobel and a Pulitzer on my wall.

I only used 80 grams of jojoba oil, because I wanted to have some left over. So the recipe was:

80 g jojoba oil
30 g water
5.5 g of lye

The soap had hardly thickened at all. I poured it into the trays, hoping for the best.

My next victim was Crisco.

Crisco is odd because it’s really a mixture of oils:

The webpage I saw recommended using a factor of .136, so that’s what I’m using:

100 g Crisco
38 g water
13.6 g lye

The Crisco soap was watery when I poured it, but I’d heard it made a fairly hard bar. We’ll see.

Now it was time for the oil that got me into this mess in the first place: Trader Joe’s Lavender Body Oil.

This is another mixture of oils:

As MOTD surmised, this isn’t really lavender oil–"lavender-scented oil" would be more accurate, as the (non-saponifiable) compounds from the lavender are dissolved in a much larger quantity of so-called "carrier oils." Happily, the first two carrier oils on the list (safflower and sweet almond) have identical saponification values of 0.136, and the third (sesame) is only fractionally lower at 0.133.

100 g oil
38 g water
13.6 g lye.

Generally, fragrances and colorants are added to soap at the end of the process (when they trace) because the lye tends to react with them and destroy whatever property you hoped they would lend. I didn’t notice that here, although I think the smell was subtly different.

The Crisco was starting to set up nicely. I poured the lavender into the molds, and doffed my goggles.

It was time for a soap family portrait:

(If you click on the photo, you can see the annotated version at Flickr.)

The jojoba looked very discouraging–to be honest, I didn’t have particularly high hopes for it, which is another reason I didn’t do as much of it. Perhaps this was a self-fulfilling prophecy, but soap and students work in different ways. I think I was just too close to the margin of error on my scale when I was making it. It’s probably only in the saponification tables to let people know they need to take it into account when they add 5 or 10% of it to a relatively large batch.

This picture reminds me of the end of Natalie Dee’s emu egg experiment.

My camera started flashing the low-battery icon just as I was taking the last pictures.

Prior: Repair, sesame, butter, and ghee.

Next: Soap tests and New Frontiers in Soapmaking!

Entry Filed under: Making Things, Soap