Wait, there was a Soap Making 101 post?

ChristmasForestSoapNo, there wasn’t. (Actually, now there is. I wrote it AFTER I wrote this post).  There are LOTS of great resources on the web to learn how to make soap. I learned primarily from the Miller’s Homemade Soap pages. It’s a clunky website, compared to how sites are put together now, and is not regularly updated anymore, but it’s still a great resource. I also highly recommend the About.com info on soap making, and tons of great resources on SoapQueenTV  put together by Brambleberry, a soapmaking supplier that I’ve been ordering from for years.


This really ugly bar was called Spokanistan, and was made before I graduated to a log mold, which requires less cutting. It was the first soap I made when I moved to Spokane, and contained Jasmine Green Tea. It didn’t look pretty, but it was a nice bar of soap.

These are all sources I trust. Yes, you can puruse YouTube videos all day and learn a lot, but there is a lot of unsafe information out there, and making soap means dealing with lye, a caustic base that can do serious damage if not handled properly (read burns and blindness). Learn good technique, use all safety precautions EVERY time, and always always always measure by weight and run any new formula through a lye calculator. My all time favorite is SoapCalc, because I can easily resize a recipe for any mold and work in percentages, but if you are new to this, you might like this one by Majestic Mountain Sage or this one by Brambleberry.

I started making cold process soap (the kind that has to cure before you can use it) sometime around 2006, after reading the Miller’s Homemade Soap website over and over, and reading the book The Soapmaker’s Companion by Susan Miller Cavitch. I was inspired to try it because I wanted control over what I was using on my body, and because I just plain wanted to understand how it worked. (I always did love chemistry.)

My first batch was a success. It was also huge. Everyone got soap that year for Christmas. Up until this year, I made a few batches every year to give as gifts, or for my own entertainment. I started selling some of it last year at local farmers markets, as an adjunct to my produce sales. This year, I got more serious about it, and made a total of 19 different batches. (I also make liquid soap, but that’s a whole other post.)


Fall soaps from this year.

Soap makers say soap making is addicting. They aren’t kidding. I spend a lot of time reading soap making forums and thinking about what I can do next. I joined the yahoo group Soap_Makers in 2010. I thought I knew some things about making soap. Turns out I was just beginning to learn. This group has taught me a LOT.


Shaving soaps are one of my specialties. Sold both in mugs (from thrift stores) or pucks.

So, this, my fellow soap makers, and future soap makers, is what I have learned about soap making in the last few years. Turns out the books don’t tell you everything. Times and techniques change. New information comes to light. Most of this I learned from the yahoo group Soap_Makers forum. Some of it came from Kevin Dunn’s wonderful book Scientific Soapmaking. A few other things I picked up from talking to fellow soap makers or watching YouTube videos. Hopefully, this synopsis will save others some time and explain some things that I wish I had known when I was just starting out.

New to soapmaking? Don’t know a gel from a trace from an FO, or the difference between NaOH and KOH? Go read some of the “new to soapmaking” links above, and come back after you’ve made a few batches. Otherwise, this won’t make much sense.

  • Once the lye and oils are well mixed, the reaction will continue, and the oils and lye will become soap. It doesn’t matter if the temperature of the oils and lye was 140 degrees or room temperature when you mixed them (though I do still make sure they are close to the SAME temperature, out of habit), it doesn’t matter if you insulate the mold or not (in fact, you can put your soap batter in the freezer, and it will still become soap), it doesn’t matter if the mold holds 5 lbs or 5 oz.
  • Holding out special oils to add at trace has no effect on which oils in the soap will actually react with the lye first, last, or not at all. The reaction is more based on the size/molecular make up of the fatty acids in the oils used. So no point in holding out special oils. Just put them all in at the beginning.
  • You can usually add your essential oils (EO’s)/fragrance oils (FO’s) to your melted oils at the beginning of soapmaking, rather than holding them out until trace.
  • The amount of EO/FO you use should be based on what your supplier recommends, but the short answer is, a lot. Typically 0.7 to 1 oz per pound of oils (that’s around 1 tsp per 4 oz bar of finished soap). So those little bottles of EO from the health food store that hold about a tablespoon and cost a ton. Not so much.
  • Using EO’s is complicated. Yes, they are “natural” in the “derived from an ingredient you might recognize” kind of way, but they are also “active”, as in “they act like medicines”. Some have restricted use amounts on the skin, and can cause photo sensitivity or serious irritation (no clove oil on the pink bits please!). A LOT of research should be done before using them. And there is no one go-to place for this information. FO’s are less expensive than EO’s, and are tested specifically for skin safety. So don’t be afraid of them.

Chocolate Vanilla Chai scent, (which is what you make when you suddenly realize that you are out of chocolate fragrance oil but already have everything else ready to go).

  • A lot of FO’s contain phthalates. This may or may not be a big deal to you. But you should be aware of it, and if your FO vendor doesn’t state which of their fragrance oils are phthalate free, be sure to ask.
    • Honey and/or other sugars (like in milks) will accelerate the chemical reaction of soap making and cause your soap to heat up (and in some cases, overheat and volcano out of the mold). Best to refrigerate any soaps with honey in them for the first 24 hours or so.
  • In cold process soap, the chemical reaction is essentially done 24-48 hours after you have poured your batter. You can do a tongue test (aka the zap test, where you put a small piece of the soap on your tongue – if there is lye left unreacted, it will zap you, kind of like chewing on tinfoil with fillings) to make sure if you are concerned. After that, your soap should cure (recommended time is 4-6 weeks), becoming milder and harder as it ages. But it is safe to use within a few days of making it (though it will “melt” in the bath or shower very quickly because of the high water content).

Had a few customers request a face soap, so I made this, which is great for, ahem…aging skin. Yup, that would be me.

  • The older the soap, the harder the bar, and the longer it will last (but the fragrance will fade over time – so it’s hard to know when a soap is “perfect”).
  • Water is a catalyst in soap making. (A catalyst helps the reaction along, but does not become part of the finished product, in a molecular bond kind of way). A really old bar of soap may have almost no water left, as most of it will have evaporated off. If you are wanting to know the lowest possible weight of a bar (for package labeling) subtract the water out of the formula to end up with the lowest possible weight it could ever be.
  • It’s really hard to get EO’s/FO’s off of your plastic or rubber utensils/stick blender completely. It’s not a bad idea to have a separate set of equipment dedicated to soap making, unless you want that bowl of homemade tomato soap to taste faintly of perfume (true story). If you are selling, then you absolutely need a separate set of utensils.


  • Soap that has gelled is not inherently better or worse than soap that has not gelled – though it will look slightly different. (Gel is just another word for melt, and it often occurs in recently poured soap due to the heat generated by the chemical reaction). So, “to gel, or not to gel, that is the question”? And the answer is up to you.
  • The flash point temperature of your essential oils/fragrance oils should help determine if you want your soap to gel or not. Gel occurs at around 158 degrees. If your EO/FO flash point is below this temperature, you want to keep your soap from gelling to help keep the scent from “flashing off”. (Edited to add: more recent information seems to indicate that this actually ISN’T a big factor, and it doesn’t really matter).
  • Some essential oils/fragrance oils will accelerate trace. Florals and spices are big culprits.
  • Vanilla fragrance oil (and any other FO’s that contain vanilla, which is a lot) will discolor your soap to tan or brown.
  • Citrus scents are notorious for not “sticking” in cold process soap. This has a lot to do with the fact that citrus scents are “top notes”, which tend to be bright but fleeting.
  • Oils high in linoleic acid (Safflower, Sunflower, Grapeseed, Hemp, Corn, Soybean) have a tendency to go rancid in soaps and cause dreaded orange spots (DOS). I personally keep any of these oils to less than 10% of my soaps. The debate about the ultimate cause of DOS rages on, and this is likely only one culprit.
  • I aim for recipes that come out to 40% saturated fat:60% unsaturated fat. This seems to yield, for me, a hard bar of soap with reasonable cure times and good conditioning properties. Obviously, exactly which saturated (solid at room temp) and unsaturated (liquid at room temp) fats you use will affect the qualities of the bar, but this rule of thumb has served me well.
  • You can add ROE (Rosemary Oleoresin Extract – NOT the same thing as rosemary essential oil), an antioxidant, to oils that are likely to go rancid, to extend their shelf life and help delay the inevitable. It WILL scent your soap slightly. In the book Scientific Soapmaking by Kevin Dunn, ROS was much more effective than vitamin E in slowing down rancidity.
  • Grapefruit seed extract (GSE), which is mentioned a lot in Susan Miller Cavitch’s books, is NOT a preservative. Preservatives prevent the growth of fungus, bacteria and molds. At best, GSE is an antioxidant. And from controlled studies, not that effective even as an antioxidant. In studies showing a preservative effect, it was determined that the effect was caused by the additional preservative added to the GSE to preserve the extract.
  • It is generally not necessary to add preservatives or antioxidants to soap. (I soap at a superfat of 5-6% – your results may vary if you superfat at much higher percentages or use a lot of high linoleic acid oils).
  • Want to resize your recipe for a different mold? Figure out the mold’s volume in inches (length x width x height for rectangles, pi x radius squared x height for a cylinder) and multiply the result by .39. This will give you the approximate number of ounces of oil that the mold will hold. I’ve now got this written in sharpie on all of my molds. I also keep copies of every recipe I make, and note how well it filled the mold.
  • In my experience PVC mold (3” vertical PVC) soaps tend to overheat and create weird holes and patterns in your soap as the heat tries to escape up through the soap. I put these molds in a cold place while the soap is reacting to keep this from happening.


  • You shouldn’t use glass to mix your lye solution. Not even pyrex. Over time, the lye will etch the glass, and eventually, it could unexpectedly shatter. Use a #2 plastic container. I use an old Rubbermaid juice container. Dollar stores are great for soaping supplies. Remember, no aluminum!
  • Lye fumes are insidious. Even when mixed outside with the wind at your back, you are probably inhaling some of them. Over time, this could do serious damage to your lungs. It would be best to wear a mask designed to protect against chemical fumes. (This is in addition to the other basic safety precautions of goggles, clothes that fully cover your body, rubber gloves and close toed shoes. I also keep a bottle of white vinegar handy, just in case. The vinegar – acid – will neutralize the lye – base.)
  • When mixing your lye solution and your oils, you only need to mix to very light trace (really, just emulsified). It does not need to look like pudding when you pour.
  • If you are wanting to play with color swirls, mix at lower (room) temperatures, mix only to very light trace before splitting the batter and adding colors, and don’t use any EO’s/FO’s that are prone to accelerate trace.

That’s it. Brain dump finished. Now go make soap!

Miles Away Farm Blog © 2012, where we’re miles away from exhausting all the soaps we want to make, and I am keeping a list of new ones to try for the spring.