This is Part I of my beginner’s soap-making tutorial. It covers the fundamental components of soap. Part II covers how to create a recipe and calculate the measurements—and gives you one of my standard recipes! Part III covers the supplies and the process.
Historically, the “acid” was supplied by the fat of an animal. The “base” was supplied by wood ash. I like to imagine that as our ancestors roasted an animal (shot with a long bow, in my imagination) over their wood fire, fat dripped down into the ash. Later it rained or they poured out water to quench the fire, and they noticed the resulting bubbly stuff was useful for cleaning their (magical) swords.
This could be all a figment of my imagination. Maybe soap was invented in some ancient laboratory by people wearing the ancient laboratory equivalent white lab coats. Either way, what is important for you to know (because I know you’re loving that stuff about animal fat and wood ash and longbows and magical swords—admit it) is that yes, you can still make soap the old way. I have never done it, however, and that is not the method I am covering today.
Instead we will use the same three basic components (acid, base and liquid) but we will use modern ingredients and cook our soap in a crock pot.
Today we have many options for the fat (acid) part of the soap:
- Traditional animal fats like tallow and lard.
- A seemingly endless variety of oils: olive oil, coconut oil, palm kernel oil, sunflower oil, sweet almond oil, apricot kernel oil, sesame oil, avocado oil, etc.
- Butters like shea butter, cocoa butter or mango butter.
Yes, all of these fats, oils and butters are “acids” (correlated: our skin’s natural pH is acidic). Most soap-makers refer to them collectively as “oils” or “fats.”
It is possible to make single-ingredient soaps (by which I mean a single fat or oil, not truly a single ingredient since you would still need the base and the liquid). Lard, coconut oil, palm oil and olive oil are all possibilities for soap made from a single fat. The butters would be less ideal as a single ingredient, but add lovely qualities when used in combination with other oils and fats.
So how do we choose?
Each fat is comprised of different types and proportions of acid constituents, each of which impart different qualities. You can find breakdowns of popular soap ingredients on the web. I have used is this one at the Summer Bee Meadow website many times. I found another at Lovinsoap.com by Googling “properties of soap making oils.”
Using these lists as a starting point, play around with different combinations on this tool at SoapCalc.net to devise a combination of oils that will impart the qualities you want.
I designed my standard combination using this tool, and know from experience that it makes lovely, bubbly, moisturizing soap: 7% castor oil, 10% cocoa butter, 48% olive oil, 25% palm kernel oil/coconut oil and 10% shea butter/mango butter.
The castor oil and olive oil I buy locally. All the rest I usually order online. I have used SoapGoods.com, Brambleberry, Soap Making Resource, Amazon, Etsy and probably some other sources I am now forgetting.
The base (or alkali) part of our modern soap recipe comes from lye. Two different forms of lye are used in soap making. In general:
Sodium hydroxide (NaOH) is used to make bar soap.
Potassium hydroxide (KOH) is used to make liquid soap.
I say “in general” because there are advanced soap making techniques—such as for cream soap—that incorporate both forms of lye. We will leave that for another day. This tutorial is for bar soap, so I will be using sodium hydroxide (NaOH). I order mine off of Amazon from a seller called Essential Depot.
Before working with lye, see these safety tips.
Our hypothetical early discoverers of soap, sitting around their wood fire roasting meat, used rain water or water from the (mystical) stream or river nearby. Modern soap-makers can get all kinds of adventurous. Beer. Tea. Goat’s milk. Even glycerin (for liquid soap).
I have made soap with all of the foregoing. Currently, however, I make bar soap only with water or beer. There are several reasons for this.
First, I am not convinced the beneficial qualities of something like cream or goat’s milk will survive the saponification process anyway. On the other hand, the sugar in beer is believed to contribute to a bubblier soap. The best soap I have ever made is beer soap.
Second, ingredients capable of “going bad” (e.g., anything food or beverage related, though I’m not sure about beer) increase the chances of the soap going bad.
Third (and most importantly for beginners), the substances in these alternative liquids can make your lye get even hotter—hot to the point of bubbling up into a little mini-volcano in your kitchen. Any liquid with natural sugars, for example (this includes beer), could get very hot.
For these reasons, I recommend using distilled water in the beginning and venturing into other liquids after careful research.
NOTE: To my knowledge, the majority of soap-makers use distilled water and not tap water. I have read different explanations for why that is: tap water contains impurities; tap water contains substances added by the utility company; tap water can contribute to the soap going bad sooner; etc. Other people use tap water and insist it works just fine.
The amount of liquid to use is calculated in different ways by different soapers. I’ve always used 38% of my total oil weight. Examples:
2.5 pounds of oils x 16 ounces per pound = 40 ounces of oils x .38 = 15.2 ounces of liquid.
5 pounds of oils x 16 ounces per pound = 80 ounces of oils x .38 = 30.4 ounces of liquid.
Some people use other calculations, such as 2x the lye weight or 3x the lye weight, as their liquid measurement. Others just use the measurement given by whatever online lye calculator they prefer to use. Several considerations to keep in mind:
- At my altitude, I can generally exceed the liquid ranges given by a particular recipe or by an online soap calculator without causing any problems. In fact, I sometimes need to exceed them or the mixture gets too dry. At lower altitudes, people may have very different experiences with the amount of liquid that works best for them.
- My bars have ingredients that make them hard. A recipe with all soft oils might do better with less moisture.
- Different oils contribute to a faster or slower “trace” (the point at which the oils, liquid and lye are all emulsified; we will talk about it more below). My combination seems to trace pretty quickly. If you had a slow-tracing combination, you might want less liquid to help it get there faster.
- If you want the bars to get hard faster, use less liquid.
Optional Other Ingredients
Fat, lye and liquid are the three fundamental components of soap. The list of optional additional ingredients, however, is endless. I’ll cover the ones I use with sufficiently regularity to merit discussion.
Salt or Sodium Lactate. I am not speaking here about enough salt to make salt bars. I mean a small amount of salt dissolved into the cooled lye-liquid before it is poured into the oils. This is done on the theory that it might make the soap bars get harder faster. I have used both sodium lactate and plain old table salt for this. The ratio I have always used is ½ t. of salt (or sodium lactate) per pound of oils used. In preparing this tutorial I noticed that the Majestic Mountain Sage online calculator recommends a higher ratio measured in ounces not teaspoons.
Sugar. Sugar is believed to contribute to a bubblier lather. There are three common methods for incorporating it, which you can read about here. The one I follow is to reserve (keep separate) a small amount (say 2 ounces) of the total liquid measurement, warm it in the microwave, and dissolve the sugar in it. Then I blend the sugar water into the soap mixture upon reaching the point of trace (emulsification). The ratio is ½-1 t. of sugar per pound of oils used.
Essential Oils. Essential oils enrich the emotional appeal of the soap. I’m not sure they add actual qualities to the soap (other than scent). Particularly in cold processing (where the EOs of necessity are added before the saponification process is complete), their qualities and scent may not survive (or may be altered by) the process. Expert soap-makers seem to agree that some EOs survive better than others.
In hot processing, the EOs can be added after the saponification is complete. I love them for their scents. However, be aware that many EOs have low “flash points.” This means that the EO evaporates or burns away at a low temperature. This can cause problems if you’re trying to add it in while your hot processed soap mixture is still warm enough to be mix-able. You can let your cooked soap cool so that won’t happen—but keep in mind that as it cools, the soap mixtures gets progressively harder to mix and mold.
Even once you get the scent firmly anchored into the soap, it sometimes fades away as the bars cure.
Does this mean you should forego EOs? No, it just means to research them to find ones that have higher flash points, long-lasting scents, work well as soap additives, etc.
The standard rate I have seen given most often for EOs is .5 oz. per pound of oils in the recipe. I’m not sure I’ve ever achieved a truly satisfying end result with this rate. The best results have been when I’ve just gone mad and poured in a shit ton of EO. I realize “shit ton” is not a very helpful measurement—but some aspects of this are more art than science. Maybe .75-1 ounce per pound of oils used?
NOTE: Fragrance oils are not the same thing as essential oils. I have never used fragrance oils for soap making. I imagine it’s the same deal as with EOs—i.e., each one has a different usage rate, flash point, propriety to the application, etc.
Arrowroot Powder. Some people add arrowroot powder to make their soap silkier. Some claim it has healing properties. I use it to “anchor” the scent of the essential oils. In other words, the theory is that the arrowroot powder will “hold onto” the EO and help prevent it from evaporating out or fading away.
The way I do it is this: I have a little condiment cup with my EOs in it. I add arrowroot powder, mixing as I go, until I like the consistency. I still want to be able to mix the EOs into the soap, so it can’t be too clumpy or it won’t mix well. But I want to feel like I’ve got all that EO “anchored.”
Again this is more art than science.
Usually the mixture separates a little while sitting on the counter waiting to get added to the soap. I remix right before adding.
Other. There is no end to the options. Some people add clay powders (like French clay). There are a variety of natural and artificial methods for adding color. You can add herbs or flowers. You can add salt. Some people add tussah silk.
It doesn’t all have to be mixed in either. You can sprinkle things over the top, or swirl them into your mixture once it’s poured into your mold. Like lavender buds or hibiscus petals or pink Himalayan salt. I have made anise scented soap bars with anise stars pressed into the center of the bar.
This is the part where you get to be an artist with the soap as your canvas.