Liquid soap. It’s lush, convenient, versatile, can be coloured or not, can be fragranced or not, can be made several different ways, can be made for hands & body, for the hair, for everything. It’s just that flexible. But – and isn’t there always one of those when things are clicking along so nicely – it can be a beast to make. Well, I guess that depends largely on the recipe used. If the wrong oils are used, it can be drying, stripping, too thick, too thin, too greasy. Too everything. The glycerin method is a hugely popular method of creating a rich, bubbly, high-emollient liquid soap and if you’ve yet to try your first batch, you’re certainly in for an eye-opening, horizon-broadening treat.
There’s nothing difficult about crafting a liquid soap with glycerin rather than water. It’s a simple substitution step. You’re replacing all of the water you’d normally use to dissolve the KOH (potassium hydroxide) with glycerin. Clear, vegetable glycerin. There’s no secret mumbo-jumbo to it. Just that. The tricky part might be in the heat used to dissolve the KOH in the glycerin. Yes, you have to have the glycerin hot otherwise the KOH will just sit there.
Heat it carefully, nowhere near boiling though or you’ll scorch the glycerin, among other hazards. Once the glycerin is warm enough, s-l-o-w-l-y add the KOH in teaspoonfuls to the heated glycerin. As each spoonful hits the hot glycerin, it will fizz up, If it gets too close to the top of the pot, simply pick up the pot from the heat source and the bubbling will go down instantly. The other important thing is to stir. Stir, stir, stir! It will help dissolve the KOH in small portions, preventing it from clumping into one huge, hard lump in the bottom of the pot. A 3 qt or so sized pot is fine for the lye portion of this recipe as it’s going to be added to the oils, NOT the other way around.
Never add oils to lye, always add lye to oils!
Once all of the KOH has been added, stir until it’s all dissolved completely. This is now ready to add to your oils pot. I’ve found that it’s a good idea to have two large stainless steel pots, 2 canning-sized pots, for this type of soap crafting. The reasons will become clear (no pun intended) as we go through the process. The oils, if any are solid and need to be melted, so use one of your large canning sized pots for the oils. Keep the other nearby as it will be needed soon. Melt the oils then allow them to cool a bit. So now you’re ready to add the KOH/glycerin to your oils which are now liquid and melted but NOT HOT! Remove the pots from the heat source. Okay, let’s move forward.
The KOH/glycerin can be added, stirring as you go with a long handled spoon for now all at once, but don’t just dump it because it’s very caustic right now. It will burn your skin! Once all of the glycerin/KOH is incorporated into the oils, grab that stick blender and start blending. Watch the phases the soap paste passes through as you blend as they occur very quickly! If your soap is too hot, it will not thicken, so let it set for a bit, then go back and try again. This is not the time to burn out your stick blender (unless you have a backup blender) trying to get the paste to thicken when it’s too hot to get there.
The paste will quickly get to a salt-water-taffy-like stage and that’s your goal. Now that it’s there, it’s time to put it back on the heat for just a bit. Not too much because the more heat you put on it, the darker it will become and as you can see in the picture, it’s IS possible to have a nearly colourless liquid soap. It will turn a deep amber if it gets too much heat, and then there’s the issue of it not thickening up when you try to stick blend it as well. So cook the soap until it tests out as fully saponified. This batch pictured took about 40-45 minutes. I used phenolphthalein to test a small bit of the paste on a paper towel. If it turns vivid pinkish purple, it’s not ready. If it remains clear, it’s ready.
So now you have a fully saponified paste. Congratulations! You’re almost there. Didn’t hurt a bit, did it! So now it’s off the heat source again, and leave it off. It won’t be going back. Here’s where that second canning pot comes in handy. The other large pot needs distilled water, heated and held, covered to prevent evaporation, until this paste is ready for it. You might want to start at a ratio of 1 part soap paste to 1 1/2 parts water. More can be added later if you want it, but if you add too much at this phase, it’s impossible to take it out. Err on the side of caution and no regrets will follow.
Now it’s reached that point so let’s use that water. Spoon or cut the paste into small portions into that hot water. You’ll find that if the paste is in small bits, it will dissolve in the hot water much quicker and evenly. Once all of it is in there, gently stir to distribute. Bubbles might occur, and make it difficult to see what’s dissolved and what hasn’t. If the bubbles interfere with your ability to observe progress, have a small sprayer bottle nearby with alcohol nearby (70% is fine) and spritz the top lightly with a fine mist of the alcohol. The bubbles burst instantly. Very cool. Let this solution rest for at least 8 hours to dissolve. Check it after 8 hours and look for any remaining lumps. The first pot can be washed as set aside in case you find lumps. After this pictured batch set overnight, I still had a few lumps, so I used that first large pot with a strainer on the top, poured the mostly dissolved soap through the strainer to remove the lumps and dissolved the lumps separately with a bit more distilled water that was heated and held (it kills any possible contaminants to heat and hold) in a quart sized Mason jar. After they’ve dissolved completely it can be added to your large pot.
Now the last and very important step. Allow the soap to cool to below 130°F if it isn’t already. Once there, add your preferred preservative according to manufacturer’s directions. Rosemary EO or Vitamin E WIll NOT act as preservatives for your liquid soap. They will extend the shelf life of certain oils, but REO and Vitamin E are not preservatives! Do not depend on them to prevent nasties from growing on your lovely soap. And after spending two days on your soap, you don’t want it ruined by lack of appropriate preservative! Some of you may be aiming towards a totally natural liquid soap, but without a sturdy preservative in place, it will become cloudy, contaminated, and moldy, which you don’t want to happen when your customer takes it home.
Now if you make this soap and leave the entire batch unscented, you can add your preferred fragrance to individual bottles with a bit of soap in the bottom, swirl it in, then add the remaining soap, rolling the bottle to blend. It will thicken and cloud up initially, but leave it for several hours or overnight to wait for it to clear up. If it remains too thick, add a bit more of your distilled hot water to the top of the soap, leave it alone for a while and see if that gets it to the consistency you prefer.
Since starting my journey into soapcrafting, over 7 years ago, I’ve come to realize that while making a loaf of cold processed soap with all kinds of glorious additives to make your skin sigh with relief and pure joy, the creation of a light golden liquid soap that slides along your skin, lathers to a towering richness on a pouf in the shower is a hugely rewarding experience to top everything else I’ve done thus far. I absolutely love making liquid soap even if it is a long journey toward the grand reward. I use it everywhere. I carry it with me in my purse when we go out, take a bottle to work to use to wash my hands, removing the grime of the shipping boxes I have to contend with on a daily basis, the germy magazines that are displayed in public serials shelves, the sticky books that require repairs before returning to circulation. Working in a library has its rewards, but it’s a dirty job, despite what many may think. Making my own soap is definitely helping to nullify the effects of that job, and the best part is, I learned soap crafting in the very same library I work in now.