Two weeks ago, I started a new bar of soap, and out of curiosity I looked at the ingredients. The ingredient list was, normal soap stuff, normal soap stuff, normal soap stuff, tussah silk.
Wait. What? There was silk in my soap?
Time to hit Google. I was surprised to find that people do sometimes put silk in their soap. It is supposed to give it a soft feel and a bit of a luster, to offset the dullness added by clay and/or mica, which is supposed to be good for the skin.
I was intrigued. I found this recipe: http://www.soap-making-essentials.com/silk-soap-recipe.html and scheduled a time on my calendar.
I think my original plan was to not worry about colors or scents, but this recipe had you divide the proto-soap into 4 cups to add various colors. I know I could have left that part out, but I wanted to try it. You can make some really pretty soaps by using multiple colors.
Here are the ingredients in my first batch of soap. Let's see if I can list off why the different stuff is included.
Coconut oil. This oil lathers well and lends hardness to the bar. The harder the bar, the longer it will last.
Shea butter: For moisturizing. In general this is supposed to be good for the skin, so you see it in many skin products. It includes compounds that aren't actually turned into soap, so the amounts in soap will be low.
Olive Oil: This gives the soap a nice feel and is good for moisturizing. Lotion bars that I've made in the past also included olive oil, if I remember correctly. You can actually make soap with 100% olive oil for the fat.
Castor Oil: Good for lather and also nourishes/moisturizes. This also will make the soap softer, so the percentage is usually kept low around 5-10%
Distilled water: Well, you need something to dissolve the lye in.
Lye: This is the heart of true soap. The lye reacts with the oils by turning them into soap in a process called saponification. Be careful working with lye. It is caustic, which means it can burn you chemically. When you add it to the water (it can react very strongly if you add water to the lye, so don't do that) it creates an exothermic reaction, which means it heats up. The couple batches I did where I used a thermometer indicated that it gets to about 170 degrees F or so.
Silk peptide: This recipe uses a silk peptide powder. I didn't have that, but I did have tussah silk that I had purchased for spinning. 18 grams is a lot, all of that in the bowl in the picture, in fact. I figured that I wouldn't be able to get all of that to dissolve and it just seemed like way too much. Further research showed that I could use a cotton ball size bit of silk, so that's what I did.
It's not as scary as it may seem.
The first step is to weigh out all the ingredients. Yes, that includes the liquids. I have a kitchen scale that I use.
My bit of brilliance that I came up with is that I bought two coffee carafes at the thrift store to use for soap making. Not the carafes that you use for storing coffee, but the ones that go into coffee pots. They are glass, so you don't have to worry about the lye reacting with it (don't use aluminum, the lye does bad things to it), they are meant to be heated and they were about $1.50 for the two of them. I got a smaller one and larger one. They work great! I may try to get a couple more for if I want to do a couple colors.
After weighing out all the stuff, I put the solid oils (coconut oil in this case) in the larger carafe. Then I put the water in the smaller carafe and placed it in the sink with the window above the sink open. I poured in the lye and stirred it with a metal whisk until it was fully dissolved, being careful not to breathe the fumes.
After the lye was fully dissolved, I added the silk and returned to stirring. The silk wanted to stick to the whisk, but slowly dissolved. Which was weird.
Once the lye and silk were dissolved, I poured this mixture into the large carafe with the coconut oil. Because the lye is hot, it melts the coconut oil. Since the other oils are liquid already, they don't need to be melted, so I added them after the coconut oil was melted.
|My carafe with the lye, silk and melted coconut oil|
This is the point at which it all gets mixed together. I hear that this can be done with a whisk, but immersion blenders (dedicated for soap making) make this part easier. You need to mix it until it reaches a light "trace". It's at trace when it looks like pudding rather than oil. It will start to not completely go flat when you remove the mixer.
Now it's time to add scent. For this recipe, it says to divide into 4 cups. I used Solo cups because it isn't as hot at this point. When weighing out ingredients, I added the color, which had mica in it, and clay to a bit of olive oil to prepare the color for the soap. It is a thin paste at this point. I added the scented soap to each cup and stirred. This bit was a bit of a pain. The soap thickened enough at this point to be difficult to pour nicely. I alternated pouring the four colors into the mold. If the soap were thinner, I would have gotten more color changes along the face of each slice.
|Soap in the mold|
It looked nice in the mold apart from where I scraped the extra off of the plastic spatula.
I tapped the mold on the counter to attempt to get out air bubbles and then set it aside for about 48 hours. I removed it from the mold and sliced it.
At this point it's mostly soap. The saponification reaction is mostly complete, but the last traces of lye will react with the last of the oils over the next couple weeks and the soap will become milder.
There is a way to speed up the last of this reaction by keeping the soap warm in a crock pot for a while before molding, but the soap still benefits from curing a bit.
Since I didn't use a crock pot, this soap will cure for the next 4-6 weeks and then I'll get to try it.
Since this post has gotten rather long, I'll discuss the next couple batches another day.
Thanks for reading!