Clay behavior in pre-trace batter

[Mobjack Bay]

Has anyone directly compared different ways of adding clay to soap batter? I think I’ve read that some add it to their oils, some disperse with water, some disperse with oil first and then add to batter, etc. I’m having a problem with some of my clays settling out after I’ve SB’d them into a thin batter (emulsified, but before trace; using for pouring and swirling) following the process below.

I’ve been measuring clay (white kaolin, green, rose, gold, so far) into a small bowl, adding my EOs, letting it sit for maybe 30 minutes and then further mixing with some of the measured, melted and mixed oils before I add it to the bulk of the oils. Then I’m stick blending to emulsion. If the clay was actually dispersing as clay size particles, the clay particles should take a long, long time to settle. Twice now I have ended up with white kaolin clay batter that is very noticeably clay-enriched towards the last quarter of pouring. It also happened once with a new batch of gold Brazilian clay. It has not happened with the green or rose clays. (I have not reminded myself what types of clay minerals are in each of these) I am whisking periodically while using the batters with the different clay colors. I’m using a slow to trace recipe and I don’t want to stick blend again because I’m trying to stay close to emulsion for pouring. The end of pouring has been at least 30 min after I started. I’m starting with a batter at around 100 to 105 DF, 31% lye and an oil mix with a good proportion of soft oils.

I can think of a couple of possible explanations, and there are probably more. The type of clay it is might matter for each of my ideas, so I’m going to need to look that up. One idea is that the “clay” is not starting in clay-sized particles. For example, see the diagram here: https://www.sciencelearn.org.nz/images/1062-relative-size-of-sand-silt-and-clay-particles. Larger particles would settle faster, maybe, like cinnamon and other spices left at the bottom of the bowl when making thin pancake or cake batter. So, maybe I’m not whisking enough, often enough because I’m trying to avoid trace. The other idea I have is that the clay is for some reason sticking to the plastic pitchers because of the way I’m soaking it/dispersing it and that the more I scrape down the sides, especially towards the end, the more concentrated it’s becoming.

I guess I’m going to try more whisking and pitcher scraping before I try dispersing the clays in water. I have the idea that if the EOs soak into the clay minerals they should be better anchored, which may or may not be the case per the many experiences and discussions here.

Have any other clay (or mica or oxide) users had a similar experience of these types of particulate colorants settling in an emulsified batter? Did you find that more mixing helped? If you use white kaolin clay, but have never seen it settle in an emulsified batter I would appreciate any suggestions you might have as to what I could try changing in my process. Thanks!

 

[SaltedFig]

Fine refined clay:
If the clay is already processed (and quite fine) I usually make a loose slurry with the clay and water at the start of making a batch (or the day before, if I'm planning ahead).
Doing this breaks up the clay into the smallest particles possible and the slurry thickens to a firm slurry (it will mound on a spoon) by the time I'm ready to soap.
I usually add the clay slurry to my soap batter (it can also be added to the oils, just before making the batter).

Refined clay with particles:
If I suspect the clay has larger particles, I either process it (described below) first, or (if I am in a hurry) I make a wet mix in a jar, soak it for a few minutes, then shake it up and run the contents through a multi-layer cotton cloth "filter" - it's the sediment that get through that contains the fine particulate I'm after, so excess water is ok - this will be poured off later.
I let the filtered water settle and when a distinct layer of sediment can be seen at the bottom of the jar, the water can be poured off and the sediment added to the soap/oils (this technique also works for making starch additives).

Unrefined clay:
Alternatively, if you have clay that is of varying textures (like an unprocessed clay), it is also possible to refine it by soaking in a larger volume of water and letting it settle (a large jar works well for this - it can be shaken up to break up the particles at the start and it's easy to see them settle at the end).
You will see, after it has settled, that the largest particles are at the bottom, clear(ish) water is at the top and the fine sediment (which is what you want) is in a layer on top of the larger particles.
Pour off the water until you just start to lose some of the sediment, then pour off the fine sediment into a container - this is the part that is nice to use in the soap.
The larger particles left behind can either be broken up and left to settle again (repeats the clay/water/shake in a jar step), filtered or discarded.

I usually do a final wash, by adding some water to the fine sediment and repeating the shake, settle and discard steps, but this is only if I've started with an unprocessed clay in the beginning.

The final sediment will be quite stiff (like oobleck).

Storing clay:
Refrigerate your clay water if you are not going to be using it within a day or so, and use it or dry it within 3-5 days.

If you are storing the clay, spread it out and bake it (to dry it out and make sure it's free of bacteria, especially anaerobic bacteria, which can thrive in damp clay). The dried clay can be powdered in a coffee blender or by using a mortar and pestle.

When you want to use your refined clay, you can make a fresh, slightly firm slurry (as per the fine clay paragraph at the start) and know that it will be like the commercial fine clays - there will be no large particles to settle.

Clay and EO's
While oil is not great for breaking down clay into fine particles, if the clay is already dry and powdered, it can be blended with Essential Oils to form a thin slurry (to add to the soap batter). It does need a little whisking, as it tends to form little clumps initially, but it will smooth out after a few moments .

 

[Mobjack Bay]

SaltedFig - Thank you for your detailed answer! It’s super helpful. I will definitely give the methods you describe a try. I noticed that my green clay seems much finer than the gold clay. I have not looked at the rose clay and white kaolin that closely. Wish I could stay home and make soap today, but it’s off to work I go.

 

[Mobjack Bay]

Following up to make note that the gold clay is definitely more gritty than the others. The white and rose clays are similar to the green clay.

 

[Mobjack Bay]

Clay and EO's
While oil is not great for breaking down clay into fine particles, if the clay is already dry and powdered, it can be blended with Essential Oils to form a thin slurry (to add to the soap batter). It does need a little whisking, as it tends to form little clumps initially, but it will smooth out after a few moments .

And this approach worked perfectly with the green and rose clays I used for the soaps I made yesterday. Since I was trying out some new FOs, I used FOs instead of EOs and also added a small amount of the oil from my melted oil mix when it cooled to < 110F. Thanks again!