For those of you with no interest in making your own liquid soap, you can stop reading now. Next week we’ll be back to our regularly scheduled programing of gardening, homesteading and cute animal pictures. Wink.
Edited 4/25/15 to add: This blog is MY opinion and MY experience with liquid soapmaking. I’ve had several readers point out that they have had different experiences from mine (with adding salt to thicken, and with the Soaping 101 glycerine liquid soap video, for example). Please note: YOUR MILEAGE MAY VARY. Feel free to experiment! Please share your differing experiences and understanding of the chemistry in the comments. That’s how we all learn from each other. This isn’t meant to be the final word on the subject. It’s just my own personal understanding and experience.
Questions about how to get started with liquid soapmaking come up a lot on some of my soap making groups, and I remember how hard it was to get a handle on it all when I started making my own, despite the fact that I’d been making cold process bar soap for years. I find myself writing out long-winded answers over and over again. So I thought I would do a bit of a brain dump on some of the fundamentals to get new liquid soapers started. Note: what this is NOT is a step by step guide to making liquid soap. If I were going to do that, I’d write an ebook. Also, apologies for lack of pictures. This is mostly an informational post.
The first thing you need to understand is that making liquid soap is not like making cold process bar soap. Had I understood this when I started, it would have saved me a lot of mistakes.
- It uses a different lye (potassium hydroxide – KOH, not sodium hydroxide).
- It’s a hot process soap, most easily made in a crock pot (though there IS a camp of people who make it cold process).
- It’s next to impossible to superfat liquid soap, because any unsaponified oils will simply float on top of the soap, because…you know…its a liquid, and mostly water, and oil and water don’t mix. There is no solid soap salt matrix to hold those extra unsaponified fat molecules in place like there is with bar soap. Therefore liquid soap won’t leave a conditioning layer of oils on your skin. Which leads to…
- The lye calculations need to be handled differently. Because you can’t really superfat, there is less room for error with your calculations. Too much lye and the pH will be too high, requiring neutralization. Not enough and you have left over fats floating on your finished soap. The lye is also less pure than with NaOH, making the calculations extra tricky.
- In order to get the lather you want (especially if you have hard water) you’re gonna need more coconut oil than you would use in bar soap. However, the “suggestion” for bar soap to keep your percent of coconut under 25% does not apply. I personally prefer my recipes to contain 40 to 45% coconut for lather.
- The consistency will not be like store-bought liquid soap. In order to get it to function properly, it needs to be quite dilute (though different oils need different amounts of dilution, which further complicates things). Think watery. If you’ve ever used Dr. Bronner’s Liquid Soap (a national natural liquid soap brand that’s been popular with the “natural foods” crowd since the 1950’s) you’ll understand what I mean by watery. This is always the most surprising thing for newbies to understand (it certainly was for me) when you make your first batch.
- Oils that contribute to “hardness” in bar soaps – like palm or tallow, really aren’t necessary in liquid soap (though you can certainly use them) as hardness obviously isn’t a factor with liquid soap.
I’ll address these facts, and how it affects how you make liquid soap, in the paragraphs below.
But first, references and where to get started.
The so-called “bible” of liquid soapmaking is Cathorine Failor’s “Making Natural Liquid Soaps“. It was published in 2000 and so is now 15 years old. I have a copy. It’s a lovely book, from a graphic design standpoint, and it contains some important beginner information about liquid soap making, like what oils will cause cloudy soap and how to thicken soap with a borax solution. But the techniques are overly complicated, passé, and the book is horribly organized. Step by step instructions on how to make liquid soap starts on page 22, the information on diluting your soap paste starts on page 41, the information on how to neutralize your soap (more on that below – it isn’t always necessary) is on page 42 – but the info on making the neutralizing solutions is on page 30, the recipes start on page 52, and no guidance is given for how long each recipe needs to cook, or how much each recipe needs to be diluted. You end up flipping back and forth through the book in a panic as you make soap, or underlining and flagging different sections (which is what I did). So, my advice is, check it out at the library and make some notes from it, but don’t bother purchasing it.
Next up, a visual/blog liquid soap tutorial from Chicken In The Road. This is often cited as the best online tutorial around on liquid soapmaking, and it IS very well done. Don’t want to buy a book. THIS is your resource. My one quibble with it is that she mentions being able to superfat your soap with castor oil. You can’t. What she means to say is that you can superfat your liquid soap with Red Turkey Oil, aka Sulfated Castor Oil, which dissolves in water. This has been pointed out several times in the comments, and I really wish she would edit the original post to change that, as it is really confusing to newbies. FYI, there ARE other oils that have been chemically altered to make them dissolve in water. Shea butter is one. They too can be added to superfat liquid soap. I’ve never personally tried any of them.
There’s a new book on the market, only available directly from author Jackie Thompson, called “Liquid Soapmaking“. I have not purchased it. I have heard that it is better than Failor’s book. If you only purchase one book on liquid soapmaking, this is probably your best bet.
A lot of the information I’m sharing here I learned from the Yahoo LiquidSoapers group, and the spin off Facebook LiquidSoapers group. Sometimes the best resource is other people to whom you can ask questions as they come up. I recommend either group. The Yahoo group has more information in their files. The Facebook group is more immediate and gratifying and you can easily post pictures.
Understanding the Lye Calculation
So potassium hydroxide, aka KOH, is the lye you use to make liquid soap. When turned into a soap salt by mixing with oils, it has a different chemical structure than when you do this with sodium hydroxide (the lye used to make bar soap). This gives your soap a different consistency. THIS is why those DIY recipes for grating up a bar of soap and adding water to “make your own liquid soap” result in soap the consistency of snot, rather than what you were expecting. Sodium hydroxide soaps want to be solid. Potassium hydroxide soaps want to be liquid. So, first up, make sure you have the right lye.
Catherine Failor’s technique for making liquid soap uses an excess of KOH. This was partially because liquid soap could not be superfatted or you’d have excess oils floating on top of your soap. It was also based on an understanding that KOH (potassium hydroxide) is only about 90% pure (the rest is mostly water that is chemically bonded to the molecules). This impurity makes calculating the lye tricky.
In the ensuing 15 years since Failor’s book was published, home crafters pushed the boundaries because 1) neutralizing is a pain in the you know what 2) they better understood how to calculate the lye correctly, taking into consideration the impurities and 3) they REALLY wanted to be able to superfat, even if it was just a tiny bit, to make a more conditioning soap.
So…with the lye calculated correctly, you do not need to neutralize, and if you neutralize anyway, you may push your soap backwards and break the molecules holding the soap salt together and end up with useless goop. But, with excess lye in the batch, if you don’t neutralize you could have a super high pH highly irritating unsafe soap.
The moral of the story is you need to know how to calculate your lye correctly depending on what you want to accomplish. Most people find that when using SoapCalc, checking the KOH box AND the 90% pure box, and then setting your superfat to +2 to 3%, you do NOT need to neutralize your resulting soap, yet you won’t have excess oils floating on top! Brambleberry’s lye calculator and the one from Summer Bee Meadows also take into consideration the lye impurity (there is no 90% box to check), but note that each calculator will give you slightly different lye amounts (frustrating). You may need to do your own experiments to see what works for your recipe. I personally prefer SoapCalc.
When starting out, keep your total oil weight to about 16 oz. This helps you avoid costly mistakes. My first batch of liquid soap made several gallons of finished product, that I scented all with the same fragrance. It literally took me years to use it all up. I will never scent anything with apple-cranberry again!
The Glycerine Method
About the time I joined the yahoo liquid soap group, everyone was all aflutter about the glycerine liquid soap method. With this method, instead of dissolving your KOH in room temperature water, you dissolve your KOH in very very hot (200 degrees) glycerine. Then you proceed as usual. (Note, glycerine is also a byproduct of the normal soap making reaction: oil + lye solution (lye and water) = soap salt + glycerine. This method adds additional glycerine beyond what is made in the soap reaction). This method has two benefits. Because glycerine is a solvent, it makes the soap reaction happen much faster, cutting down your trace and cook times. It also makes stirring the resulting cooking soap paste, rather than just mashing it around, actually possible.
An example of this method can be found in this Soaping 101 video. (A few notes on this video – she uses a 2:1 glycerine to KOH for her lye solution. Convention is to use 3:1. If you watch carefully during the pour, you can see that her solution still appears chunky with KOH flakes – yikes! I’ve also found this recipe to have almost zero lather in my hard well water. As this is a Bastile recipe – yes, she calls it a Castile, but its not, as Castile would be 100% olive oil – and less than 10% coconut, this isn’t that surprising. But I don’t recommend it unless you have super sensitive skin and/or a water softener).
Turns out mixing a highly caustic substance on my stove, heated to 200 degrees, makes me incredibly nervous. Lye fumes in the house. A substance that, if spilled or splashed, could cause both heat and chemical burns. I’m brave, but I’m not that brave. I tried it. Once. There are also some who think that excess glycerine makes a soap more drying. We don’t need that, as we’re already fighting that by not being able to superfat as it is. Plus, glycerine adds to the cost of the soap. So my personal compromise is to dissolve my KOH in 2x its weight in water, stirring until fully dissolved, then adding the additional 1x KOH weight in liquid vegetable glycerine, and proceeding as usual. (I mix my lye solution outside, while I’m standing upwind.) I feel like this gives me the best of both worlds. Experiment as you wish.
Use a crock pot. Seriously. The whole double boiler method that Failor uses…ugh. Way too much work. You can buy used crock pots at thrift stores for next to nothing. Buy one just for making soap. I stick blend in my crock (off and on if its taking a long time to come to trace) until the mixture is too thick to stick blend any more. Then I stir it about every 15-30 minutes, while keeping the heat on low. DO remember to stir (or really, mash about – soap paste is so thick its like silly putty – its next to impossible to actually “stir” – another thing Failor doesn’t really tell you in her book). It can climb up the sides of the crock and spill otherwise. After an hour or two it will stop doing that. Note that depending on the oils used, it can take 8 to 10 hours to fully cook your soap! I start doing small clarity dilution tests after about 3 hours.
Testing for Excess Lye
You’ll see information on diluting a bit of soap paste in water and observing it for “cloudiness” or “milkiness” to see if your soap is done cooking (testing for unsaponified fatty acids). This is all well and good, but depending on the oils you used, it may never test clear, and if you have excess lye (accidentally or on purpose) you won’t know it from this test. So, I highly recommend buying some 1% phenolphthalein dissolved in ethanol. You can find a couple of ounces of it on Amazon for around $10 and it will last you a LONG time. Phenol is a pH indicator. You put a drop of it on a bit of your soap paste (removed and put into a separate container) and it changes color, from light pink to deep magenta, in a pH range from 8.2 to 9.8 (darker = more alkali). No color change or only a very slight color change and your soap is fine. Big color change and your soap needs to be neutralized with a borax or citric acid solution (carefully, adding only a little at a time – remember, too much – especially of citric acid, and you will break the soap salt bonds and end up with goop). Potassium soaps naturally fall into the 9.5 to 10 pH range. Interestingly, Failor’s book talks about using Phenol, but doesn’t tell you the pH range it tests for. pH strips are useless. Don’t buy them. Don’t rely on them. If you have a pH meter, by all means use that, noting that your soap needs to be quite dilute for it to read accurately.
One of the best tips I ever got from the yahoo group was to dilute your soap paste starting with 2x the weight of the OILS in the recipe, not the paste weight. Paste weight is hard to estimate. You have to remember to weigh your container before hand, so you can weigh your container and finished paste at the end. Some of the water you used is going to evaporate off and you need to know how much has been lost. You need to account for any paste removed for doneness testing and/or phenol testing. It becomes a math nightmare. But the amount of oil used doesn’t really change – except for the small percentage removed for testing.
How do you know when you’ve diluted your paste enough? One, the paste will be fully dissolved. This can sometimes take up to 24 hours, so have patience. No more chunks floating around in there? Good. Now, is there a skin forming on the top of the diluted soap? Kind of like the skin on a pot of boiled milk that has cooled on the stove? Then you need to add more water until no skin forms. Hot soap will not form a skin while room temperature soap will, so it needs to be cool to know if you’re gonna form a skin, but warm soap/water will dissolve faster. Different oils take more water to fully dilute. You can always add a bit more water, but its a pain to heat your soap to evaporate off water if you have added too much. Start conservative, have patience, and add only a little bit more at a time (say, 1/8 cup) until you stop forming a film on top. If the soap seems too concentrated at this point, i.e. its hard to wash off your hands, you can always continue to add more water. Keep very good notes.
Neutralizing If You Need To (taken directly from Catherine Failor’s book)
- Borax (20 Mule Team – NOT Boric Acid) 33% solution: 3 oz borax dissolved into 6 ounces of boiling distilled water. Borax is a buffer and can also be used to thicken liquid soap. Some people love it. Others aren’t comfortable using it. Great blog post on its safety here.
- Citric Acid 20% solution: 2 oz citric acid dissolved into 8 oz of boiling water.
For one pound of soap paste – diluted with water to appropriate final consistency (you can’t stir your neutralizer into your paste – its too thick and it won’t disperse), add 3/4 oz (approx. 1 1/2 tbsp) borax or citric acid solution, as described above. Stir well. Test again with Phenol (always by removing a sample – never directly into your soap). Add more solution in smaller increments if necessary. It’s easier to over do it with the citric acid. Maybe start with half the amount recommended by Failor, and add more if necessary. Her recipes were purposefully lye heavy.
Failors soap book, and other references around the internet, will have you believe that clear liquid soap is the holy grail of soap making. That somehow clarity equates to quality. I have NO idea where this idea came from. I personally could not care less. We all grew up with opaque pearlized soft soap and never blinked an eye at its lack of clarity. The following oils will make clear liquid soap: Almond, Canola, Castor, Coconut, Olive, Palm Kernel (a sub for coconut), and Soybean. There are probably others (sunflower, apricot kernel…). Oils that will result in a somewhat to quite cloudy soap are palm, tallow, lard, jojoba and most butters. This likely has to do with the fatty acid make up of the oil, along with the unsaponifiable components. If you really desire crystal clear liquid soaps, only use the oils that produce them, and then also sequester your soap for 2 weeks to a month after its diluted so any unsaponified substances have time to sink to the bottom or float to the top. Then somehow carefully decant JUST the clear soap, leaving the rest behind. Good luck. Grin. Again, I think crystal clear soap is WAY overrated. I’m much more interested in how it feels on my skin.
After the basics, this is probably the most common question asked on liquid soap making groups. “How do I thicken my liquid soap?” We all want our soaps to be the consistency of the soft soap we remember from our childhoods (but heaven forbid it not be clear – go figure). There are a variety of answers. I am personally OK with watery liquid soap, so I have not tested most of these. I simply put my liquid soap in foamer bottles. Problem solved. I’m also trying to keep the list of ingredients to a minimum, and to substances most people would recognize. If you do play with these possibilities, be sure to follow the manufacturer’s suggested directions and use rates.
- Borax – as discussed above, or in higher concentrations. Seems to be a bit hit and miss. I’ve had it work quite successfully with a coconut (15.5%), canola, olive and castor formula.
- Salt – 1/2 oz table salt dissolved in 1 1/2 oz warm distilled water. Add 2 tsp per pound of finished soap to start. Reportedly doesn’t work with soap that is more than 20% coconut. Also may make your soap somewhat pearlized.
- HEC, Hydroxyethylcellulose. Can be used up to 1% as a thickener. Will feel slimy if too much is used. Add to dilution water at room temp. Then slowly heat water to fully dissolve. Then use it to dilute your soap. If not dissolved properly, produces “fish eyes” of undissolved HEC.
- HPMC, Hydroxypropyl Methylcellulose. Add to boiling water and stir occasionally. Thickens as it cools. Can be added to liquid soap that is already diluted and is too thin (add directly to diluted HOT soap). Use at around 1% of dilution water.
- Liquid Crothix. Add directly to soap at room temp. 1-8%. I’ve seen good things reported. I have not tried it.
There are also liquid soap recipes that use a mix of KOH and NaOH in order to achieve a thicker liquid soap without additional additives. The starting ratio seems to be 60% KOH and 40% NaOH. I have NOT tried this method. Please do your own research on this technique, and let me know the results! Note, adding NaOH will compromise clarity.
This is a hotly debated topic in the liquid soap world. There are those (including Failor) who say that the pH is high enough that nothing nasty is going to grow in there (it should be noted that Dr. Bronner’s soap does NOT contain a preservative). There are those who say that water = medium for nasties to grow, and a preservative is necessary. There are those who say that they are only needed when the soap is diluted enough for a foamer. There are those who say that you should never ever use anything but distilled water for your dilution (THIS I agree with). No teas, no goat milk, no aloe etc. – though there are methods for using these substances in your soap PASTE – I have not tried them. I don’t personally add a preservative to mine. If its good enough for Dr. Bronner’s (again, been in the market place since the 1950’s), its good enough for me. But its a decision you should research for yourself. It is difficult to find preservatives that are effective at a pH higher than 8. This is a good overview of what’s available.
So, after all of this learning and experimentation, I have found that liquid soap does not sell as well for me at market as my bar soap does. I thought for sure I’d be winning over new customers who don’t like to bathe with bar soap when I added it to my line. But this has not proven to be the case. I think a lot of this is cost. My packaging on my bar soaps cost me pennies. My packaging on my liquid soaps costs me dollars. There’s a bit of sticker shock involved when compared to big box store products that are so inexpensive. I make a few batches a year, for our own use in soap dispensers around the house, and for the small group of my customers who really do prefer it. But it hasn’t turned out to be the niche market I had hoped it to be. Hopefully my experience will not be yours.
Miles Away Farm Blog © 2015, where we’ll be introducing “soap saver socks” at this year’s market, which hold a bar of soap for ease of use and drainage, with the added benefit of being in an exfoliating wash cloth at the same time. Hopefully this will convert the “commercial shower gel” users to try hand crafted soap!