Soap 2

In which I make soap but do no damage to my kitchen.

Melting the tallow

I melted the 1kg tallow from Tallow 3 over heat low enough to produce no steam or smoke. I combined 120g of slightly lumpy (not completely anhydrous) sodium hydroxide lye and 325ml of water, let it cool, then added it slowly to the warmed liquid tallow.

Stir, stir, stir

Very little soap floated to the top, but every time I stirred the mixture, more light colored solids accumulated at the bottom of the pot. I had expected that the soap formed would rise to the top, and indeed some fluffy soap-like curds did come to the top, but the more viscous and cohesive mass stayed at the bottom. The more I stirred, the more formed. I kept the heat at the minimum setting throughout. I ended up with something that looked more like applesauce or loose tofu than soap.

Set

When the stirring produced no further solids, I stopped and turned off the heat, and left it overnight. During the night the saponification completed normally. I ended up with a thick cake with rice-crispie-sized pellets on top, and a very thin layer of clear viscous liquid at the bottom. This cannot be the whole of the glycerin, since it's not even 5ml of liquid. A quick swab with some litmus paper shows it as extremely alkaline, so I assume some of the sodium hydroxide went unused and collected here.

I am not shaping the soap at this point, I'm just setting it aside as large cakes for later use.

Glycerine 2, Soap 1

New attempt:

• 380g tallow
• 5 oz water
• 86g store bought lye (WAY too much due to miscalculation)

1. added the lye to the water and let it cool.
2. melted the fat completely and let it cool for a minute or two
3. combined the two and mixed lightly
4. poured into a glass container and set aside to cool overnight.

Result: still an unseparated emulsion in the morning.

Tallow on the scale

Lye and Water Mixture

Melting before adding lye

Unseparated result

After 24 hours it was still pretty much a homogeneous gel, so I "remade" it:

1. melted it over a stove
2. added a cup of water (to aid in melting)
3. added a cup of vegetable oil (to balance the excess lye)
4. left to cool in the metal pot I did the melting in

Result: Really granular/void-filled soap, but definitely soap.

I also collected about a cup of water and a couple ml of cloudy glycerin

The soap was still really granular, and when I squeezed it I got a lot more glycerin. So I divided it into three balls and wrapped them in cheesecloth, then pressed them. This produced dryer soap and more glycerin, but not much more water.

Next note: Decanting two separated liquids is hard without the right equipment. I think that if I were doing this at scale I'd probably find it useful to make some specialized equipment

Day 6: The balls of soap are still in their cloth and still very slick. I think they're still exuding a bit of glycerin. But they do work as soap.

Day 20: The soap is now hard enough to be considered ready

P.S.
Lye is hard to find these days. Went to 2 hardware stores, a supermarket and 2 drugstores. No dice. Ordered it from Amazon instead. Easy.

Glycerin 1

I attempted to create glycerin today using some "suspect" lye (a brown powder produced from potash rather than a white one from the store) and some beef tallow.

I melted the tallow in a pot, and mixed in double that volume of water, in which I had dissolved a half mole of lye. A white fluffy-looking layer immediately formed on top of the mixture, which I suspected might be a soft soap. But when I tested it, it was still very greasy, and very alkaline.

I set the whole mixture aside and let it cool. This took a surprisingly long time. (I think the alkali was still doing its thing and generating heat) After a bit I put it in the fridge to accelerate the cooling. Later I returned to find no glycerin layer at all, and a strongly alkaline and greasy layer where I had expected to find soap. I mixed in enough vinegar to neutralize the mixture, and set it aside to settle again. Two hours later there were still only two layers, when I had been expecting three.

I suspect I either used an inappropriate amount of lye, or that the lye was contaminated.

Lye 1

I attempted to make lye today, with questionable results.

I mixed 1/2 mol of quicklime in water, and got the expected:

1. Sizzling reaction
2. Exothermic reaction heated water
3. Flocculant result

I then added 1/2 mol of slightly suspect potash (it's brown rather than white, see potash discussion) and got pretty much what I expected: a chalk precipitate and a slightly brownish liquid. I had used a lot of water, so the boil-down took forever. I stopped when I had maybe twice as much fluid as it would take to dissolve a half mole of lye, and transferred the liquid to another vessel, figuring that the precipitates so far would be something other than lye. Boiling the remainder dry gave a dark brown paste, then powder. It was highly alkaline.