After getting a nice piece of brine soap to test from
@geniash, I decided I would like to make my own brine soap. I also discovered that I still have some pink salt that I would like to use up. Dissolving and then recrystallizing the salt, which is what I described above, does not ensure 100% that there are no sharp mineral particles left as contaminants in the salt. When I made my salt powder using the method I described above, I did not see any residue in the pan after I dissolved the salt, but I did not filter the brine, which means I can’t be certain everything dissolved. A salt bar I made from the powdery salt described above doesn’t feel scratchy to me, but others may be more sensitive, or the scratchy bits could be very dilute and maybe I just haven’t encountered one yet. To be ultra safe, here’s my refined method for saving myself and others from any scratchiness in soap due to using pink Himilayan salt.
For this run, I dissolved 50g of salt in distilled water and then passed it through a piece of 30
um mesh Nitex screen cloth I borrowed from my lab. For comparison purposes, most of the micas I use are in the 20-60
um size range. A geologist would classify these micas as silt size, rather than clay, which is classified as < 4
um according to something called the Wentworth scale. What I ended up with in the jar is a mixture of brine and particles < 30
um in size. It looks like most of the color is associated with particles. The screen cloth retained 0.09g (still damp) of pink, dark and clear minerals that wouldn’t dissolve. According to the web, a coffee filter has a pore size of 20
um, so that should work if you want to try this and don’t have a piece of Nitex laying around
. I wasn’t thinking and used way too much water for a brine solution, so I will need to let it evaporate before I make the soap.
The first photo shows the jar with the brine right after I made it, as well as the residue retained by the screen cloth. The second photo shows the brine after about 2 hours of sitting undisturbed. You should be able to see the pink particles that have settled to the bottom and how much clearer the overlying water is. The third photo is a close up of the residue from the screen. The particles retained on the screen are still fairly small, but they do look like they could be scratchy. If I decide make salt powder again, I will filter the brine water first and then recrystallize the salt.