Soap Much Misinformation: Twelve Common Soap Making Myths Explained

Updated: Oct 25




When I was first learning how to make soap, there were very few readily available resources for learning the craft and science of soap making. I had a collection of Rolodex recipe cards that had handwritten recipes measured in cups, spoonfuls, and cans that were passed down through family members and close friends, as well as a handful of books from the 1970s and ’80s that were rented from my local library. The mass influx of soap making blogs, YouTube channels, pictured recipe books, classes, and other present forms of learning were not yet created, and most of my learning was done through personal experimentation (many of which failed miserably). Simply obtaining supplies required getting them only from local stores or ordering them by phone and waiting several weeks for them to arrive, rather than ordering online directly from a large cosmetic and soap supplier or getting them next day air from Amazon.


Thankfully, modern soap makers have so many different resources, tools, and options available at their fingertips for learning both the science and art of soap making, that the days of experimenting, guessing, and hoping things turn out “good enough” are things of the past (-unless you are like us and enjoy running your own experiments of course!).


Unfortunately, with so much information available comes the completely avoidable, yet somehow inevitable opportunity for misinformation. Some of this misinformation comes from decades of soap making experience before us that has yet to catch up, and other forms come from a lack of experience and knowledge from eager soap makers and bloggers who simply wish to share their work with others. Whatever the cause or reason behind it, it is important to correct this misinformation in order to keep everyone safe and help promote and support the growth of an educated soap making community.


We have compiled a list of some of the most common things that we were taught by the soap makers before us that we have since learned were incorrect or included misinformation. Many of these things we had previously repeated, and some of them we even taught, simply because we were not educated at the time. We are all human beings and learn from mistakes and by sharing the list below, we hope to prevent some of the common mistakes that many soap makers are still repeating today.


  1. Soaping Myth: Glass bowls and containers are safe for use in soap making When I was growing up, my grandma used to mix her lye solution in many different containers, including glass mason jars. She taught me that aluminum was never to be used because it reacts with the lye and that the glass mason jars were “safe” because the lids were made from stainless steel. She also used Pyrex containers so that she could see what was happening with her soap. Even today, some of the most popular and influential soap makers use glass in their tutorial videos and blog posts. Soap Queen is the perfect example of this, and all of her photographed and video tutorials include mixing her lye solution and soap in a large glass container. Because of this, many new soap makers also create their lye solutions and soap in glass containers and go on to repeat the same thing in their videos and tutorials. If both historical and modern soap makers teach their audiences to use glass and regard it as safe, why is this first on our list of soaping misinformation? There are many types of glass and each is different in terms of its chemical composition, the method used to produce them, and their processing behavior. While some types of glass, such as borosilicate glass, a commonly used type of glass for laboratory glass, and some older Pyrex containers, are more resistant to chemical alterations, many of the glass containers soap makers attempt to use are easily degraded and chemically etched by lye. The glass reacts with sodium hydroxide to form sodium silicate. Because our cold process soap is only 10-15% saponified at trace, even using a glass bowl purely for soaping can have serious complications (Fun fact- you can dissolve glass with sodium hydroxide, google that for fun!) When the temperature is increased, this rate and risk of chemical degradation increases. Both the creation of the lye solution and saponification produce heat. Compromised glass containers will break and shatter. Not only is chemical degradation a risk, but glass can also be chipped and broken from outside forces, such as dropping the container, which would contaminate the entire soaping area. The last thing we want any soap maker to experience is a contaminated soaping area or a shattered container that leaves glass shards and hot caustic liquid spilled everywhere. If glass is not the best option, what should you use instead? When looking for soap-safe materials, materials that are chemically resistant to hydrated sodium/potassium hydroxide are best. These include both stainless steel and polypropylene. Not only are these materials both rated for safe use with sodium hydroxide, but they are also shatter-resistant and have high melting points. This concept also applies to the soaping utensils that you use such as spoons, spatulas, and whisks. You should use chemically resistant materials for these as well, avoiding thin flimsy plastics and wood. We have written an article about chemical-resistant and safe soaping materials here.

  2. Soaping Misinformation: Soap is moisturizing and conditioning. When I first made the switch from commercial cleansers that were causing irritation to the bar soap my grandmother had specifically made for me, I was both totally impressed and relieved. I finally found a product that didn’t cause my skin to feel dry and irritated. My skin felt calm and moisturized for the first time in a long time, and when I spoke of this to others, I continued to mistakenly claim that the soap moisturized my skin. I even made the mistake of using this incorrect wording in my first draft of UG2HP and it wasn’t until a student asked me “How do I make my soap even more moisturizing?” that I realized the error in my messaging and that it was perpetuating a very commonly shared myth- that soap is a moisturizing or conditioning product. While switching cleansers did reduce the irritation and stop the drying I was experiencing due to the other products, the soap itself was not and is not a moisturizing product. Unfortunately, soap is a cleansing product made from surfactants that are intended to do one thing- remove dirt and oil. But why does the soap calculator say that some of the oils are conditioning and if I use more of these in my recipe, won’t it moisturize and condition my skin? First, let’s take a look at what conditioning means. Conditioning is a blanket property that does the following: adds water or moisture to the surface of the skin (humectant), provides a barrier for abrasion or water loss (occlusive), adds or replaces lost fats (occlusion), and/or smooths and soothes the skin. Soap is a cleansing product and is not able to do any of the above-mentioned things. While you can certainly include additives and increase the superfat (free fats in the soap) which add moisturizing and conditioning properties, these are often a very nominal part of the total formula, and they are not going to be effective at producing an overall product that will truly moisturize or condition. Always keep in mind, the general purpose of soap is to clean, which is truly an extraordinary feat in and of itself! If you are seeking to condition or moisturize the skin, consider the use of leave-on products that can be applied after cleansing and drying the skin such as lotions, body oils, body butters, and more. Each of these types of products is designed and formulated to provide the properties listed above, and more! To add even more to this topic, soap will not lighten the skin, increase fertility or balance the pH of the vagina (common false claims about Yoni soaps, learn more about these here), cure physical ailments, or any of the other extraordinary claims that are being made. It is a product intended to cleanse the skin and while as wonderful and amazing as it may be, it cannot perform extraordinary acts like those mentioned above or through many of the popular false advertisements. If your soap is formulated as a cosmetic, a product intended to beautify, not permanently change or alter the composition of skin, it may be marketed and reported as such with terms like exfoliating, softening, brightening, refreshing, etc.

  3. Soaping Misinformation: When preparing additives and ingredients, it is best to use PPO (per pound oils) and units of volume such as teaspoons, tablespoons, drops, cups, and fluid ounces. When I first started making soap, I used recipes passed down from my family members that would include things like “10 cups of water, 10 cups of lard, and 1 can of lye”. At the time, I didn’t second guess the recipe and how it was formulated because that was the only information that was provided to me, not to mention, my family members had been using it to create great soap for years and years. Of course, we now know today that soap making is both an art and a science. We know that every oil molecule (triglyceride) requires 3 NaOH molecules to break the bond between the fatty acids and the glycerol molecule, which results in three soap molecules and glycerin. We have amazing information and tools that allow us to calculate our formulas with the exact amount of each necessary ingredient so that our formula results in the soap we want- with the properties, performance, and appearance that we dictate through an informed formulating process. We know that when formulating a soap recipe, we should use ingredient and additive weight, not volume. Weight and volume are mathematical and scientific quantities used to describe objects in space. While they are often used interchangeably to mean the same thing, they are in fact very different. Weight refers to the pull of gravity on an object (what some may call its “heaviness”). Examples of units of measurement of weight include grams, ounces, and pounds. Volume refers to the amount of space that an object takes up, and includes cups, spoonfuls, and fluid ounces. I am personally guilty of using volume for additives up until a few years ago because I only worked with students in the U.S. at the time. When I started working with students across the globe, I found how difficult it was to teach using this method and honestly, how inaccurate it was. I provided measurements like “One teaspoon of sugar PPO (per pound of oil)” just like my teachers did, and just like most of the modern soap makers still currently do. While you won’t find recipes written with “1 can of lye” anymore, you will still find that a large percentage of blogs, recipe books, and tutorials use this same outdated PPO-volume measuring system. Units of volume are incredibly inaccurate when preparing cosmetic formulas and it is even more difficult when correlating with the metric system and/or resizing the formula. Imagine trying to resize your formula using the “one teaspoon of sugar PPO” example above from a recipe that uses 1 pound of oil to a masterbatch-sized recipe that requires 50 pounds of oil. You would have to physically measure 50 teaspoons of sugar! That would be time-consuming and incredibly inaccurate. Then comes even more questions- Are they flat-spoons or rounded-spoons? Does more or less of the ingredient create an unsafe product? And so forth. If measuring in units of volume and using “PPO” are inaccurate and outdated, how can we easily prepare ingredients and additives by weight for our formulas? I have personally found it both accurate and seamlessly easy to prepare ingredients by a percentage of the total oil weight. This is applicable no matter what unit of weight you are using (grams, ounces, or pounds) and it easily resizes. Using the sugar example above, if instead, we formulated our recipe with 2%TOW sugar (2% of the total oil weight), we would be able to easily calculate the weight of sugar for whatever recipe we needed. This is not only much more accurate, but it is also universal and can be applied to everything included in our formulas- from additives to fragrance, oils, and butters used, and even the water content!

  4. Soaping Myth: Do not use more than 5% castor oil in your recipe or it will result in a soft and sticky bar If you use any of the common “recommended oil percentages” resources found in most blogs and books today, you will notice that most of them recommend no more than 5% castor oil. These resources state that adding more than 5% castor oil will result in a bar that feels tacky, sticky, or simply won’t harden. For those of you who have made any of our UG2HP hot process recipes, you will notice that most of them use 15-20% castor oil, and every one of our recipes produces a bar that is not only quickly hardening, but also very bubbly. Contrary to popular belief, a higher concentration of castor oil does not always result in a formula with negative soap qualities. In fact, a 100% castor oil soap rapidly saponifies and hardens very quickly compared to most other single oil soaps. Castor oil is comprised almost entirely of an unsaturated fatty acid called ricinoleic acid. Ricinoleic acid is unique when compared to the other fatty acids used to make soap because it contains a little OH group on the end of its carbon tail. This OH group acts as a solvent and does things like increase the reaction rate of saponification (and thus trace) and increase the solubility. Ricinoleic acid saponifies into the soap sodium ricinoleate and when used in our formulas, it increases the total solubility. Even at smaller amounts, such as 5% of the total oil weight, sodium ricinoleate has a significant impact on the solubility rate and can help with increasing the lathering abilities of your soaps. While it does not create bubbles itself (contrary to what many soap makers have been taught; sodium ricinoleate actually has reduced bubbling/lathering abilities), it can help create a more bubbly soap when used with other types of soaps due to the increased solubility. (Side lesson- SoapCalc includes ricinoleic acid in the calculation of the “creamy” property, which is not necessarily the case and we do not recommend including this in your possible property outcomes when formulating) Because ricinoleic acid is an unsaturated fatty acid, it can produce a softer soap when compared to other soaps, and using too high of a concentration in a formula that is high in other unsaturated fatty acids (such as a castile soap) can have the negative impacts that are reported by many. However, if used in a formula with more saturated fats, especially more palmitic and stearic fats, it can be an excellent addition that can add softening properties and excellent lathering qualities to the overall product. In liquid soap, higher concentrations of castor oil will help with clarity, an accelerated saponification reaction, and a faster dilution rate. In both our liquid and our bar soaps, we love to use higher concentrations of castor oil and find that it really adds positive qualities to our formulas.

  5. Soaping Misinformation: Soaps with a low cleansing property value will not clean Soap calculators are an amazing and wonderful tool, and they provide an enormous amount of insight into the possible qualities our finished formulas will exhibit. Unfortunately, the information provided can also be misleading and lead novice soap makers to believe misinformation like the statement above. If you entered a Castile formula, or a 100% olive oil soap, into your soap calculator, you would notice that it displays a “0” in the cleansing value. This is because this value is determined by the total combination of lauric and myristic fatty acids and olive oil does not contain these fatty acids. Beginner soap makers often assume that the soap will not be able to clean because of this and will try to reformulate their recipes to raise this level. Unfortunately, this is not the case- all soap cleans. Nearly all compounds fall into one of two categories: hydrophilic (“water-loving”) and hydrophobic (“water-fearing”). When water and oil are mixed, they separate and form two distinct layers because hydrophilic and hydrophobic compounds don't mix. Soap is unique in that it has both a hydrophilic and a hydrophobic end. The hydrocarbon chain from the fatty acid is non-polar and hydrophobic so it is repelled by water. It binds to dirt, grease, and oil. The "salt" end of the soap molecule is ionic and hydrophilic so it is water-soluble. Because soap molecules have both properties, it can act as an emulsifier. An emulsifier is capable of dispersing one liquid into another immiscible liquid. This means that while oil (which attracts dirt) doesn't naturally mix with water, soap can suspend oil/dirt in such a way that it can be removed. The soap will form micelles and trap the fats within the micelle. Since the micelle is soluble in water, it can easily be washed away. All soap molecules are surfactants and allow dirt and oil to be suspended and washed away by water. Knowing this information, we can easily acknowledge that all soap will help us get clean, even if the soap calculator states that it has no cleansing properties.

  6. Soaping Misinformation: Hot process soaps do not need to cure and can be used and sold right away While the above statement has started to fade as more information has become available, it is still a very commonly shared soaping myth. We still see many soap makers claim, “I only make hot process soap because I need to sell it the next day and hot process soaps don’t need to cure.” Unfortunately, this couldn’t be further from the truth. Both hot and cold process soaps benefit from curing. Curing hot process soap results in a product that is harder, longer-lasting, is less prone to cracking and water uptake, has better lathering properties, is milder due to an increased glycerin content and lower pH, and so much more. We feel that many novice soap makers may not be familiar with the difference between saponification and curing, which may lead them to believe they are the same thing, thus creating some confusion on this topic. Because of this, we wrote a full blog post on the benefits of curing hot and cold process soap, which can be found here.

  7. Soaping Misinformation: Using more than 10-15% coconut oil or using a recipe with a higher cleansing value will always result in a bar that is drying and stripping My family had always used recipes that were lower in “cocoanut” oil (as the old recipe cards and books used to say) because many of them had sensitive skin. I also have incredibly sensitive skin that reacts with just about everything from cleansers to lotions, fabrics, and even the sun and wind. My skin sensitivity is what first inspired me to start making my own soap and cosmetic products. I wanted to be more in control of what I was putting in and on my body in hopes to reduce complications like irritation, drying, redness, and more. Because I initially relied heavily on my family’s recipes and because of the commonly shared notion that higher coconut concentrations or cleansing values always resulted in formulas that were more cleansing, I tended to steer clear of anything that might increase the risk of irritation and drying. Many of my earlier formulas used very little coconut oil and other similar oils that contained more cleansing fatty acids, although if you take a look at my formulas now, you will notice something very different. We know that coconut, babassu, palm kernel, and other oils with similar fatty acid profiles have a higher concentration of two unique fatty acids- lauric and myristic fatty acids. These are short-chain saturated fatty acids that are much more soluble, even in conditions where soap solubility is significantly decreased such as water that is hard (mineral-rich), cold, or salty. Soaps made from lauric, myristic, and similar short-chain fatty acids have the ability to bind to and remove natural proteins and fats found on the skin’s surface which protect the underlying tissues. If a formula is made with too high of a concentration of these types of fatty acids, without any other mitigating factors, it can cause too much of the skin’s normal protective barrier to be stripped away, leaving it feeling tight, dry, and irritated. This is not the case for all skin types, but for those with more sensitive, troubled, or compromised skin, it can cause exasperate these negative effects. While higher lauric and myristic fatty acids can lead to irritation when included in an unbalanced formula, they also add positive qualities to our soaps like a full, white, and fluffy bubbly lather. This is something most people love and expect when using soap because they are used to commercial non-soap surfactant products. These types of soaps also add to the total hardness of the bar, which is important if you are using more unsaturated fatty acids. Can you have a bar that has both a full and voluminous bubbly lather made with more lauric and myristic fatty acids and also one that does not lead to drying and irritation? Absolutely! There are many things that can be done to increase the mildness of a soap formula so that you can have the best of both worlds. Some of these include the addition of skin-softening and conditioning additives such as cetyl alcohol, sorbitol, and sodium lactate, increasing the superfat to reduce the cleansing ability, and decreasing the solubility concentrations of the other fatty acid salts. A 100% coconut oil soap made with a 30% superfat is the perfect example of a high lauric-myristic fatty acid soap that has been reformulated to include a higher superfat and decrease the cleansing ability of the product, thus leading to a formula that is both milder in nature and has the benefits of a voluminous and full bubbly lather. While many of my previous formulas used to stick to around 10-15% of coconut oil, I found that my lather qualities just weren’t what I was expecting and by learning more about the formulating process, I was able to increase my coconut oil (or other lauric/myristic oils) to increase the lather volume without increasing the harshness of the product by reformulating other aspects of the recipe.

  8. Soaping Misinformation: Fragrance and essential oils should be used at 5% or 1 ounce per pound Every essential and fragrance oil will have a unique recommended safe usage rate, which is based on the supplier’s recommendations and IFRA standards. IFRA, or the International Fragrance Association, was created to help promote the safe use of fragrances within the cosmetic industry. Fragrance and essential oils pose risks that include things like dermatitis, irritation, redness, drying, peeling, burning, and more, if used at concentration in a product that has been deemed unsafe by the supplier’s rigorous testing. It should be noted that the usage rates are not the same for every essential oil or fragrance oil because they have different chemical compositions and are processed differently. Thus, there are no general recommendations such as “Fragrance oil should be used at 5%” because this is not applicable to all fragrance or essential oils, and recommendations such as these should be regarded as misinformation. For example, with certain cinnamon fragrance oils, the maximum recommended usage rate may only be 1-2%. If you followed the above guideline, you would be creating a product that has unsafe levels of fragrance and could cause skin complications. How do you know how much fragrance or essential oil is safe to use in your soap? Follow the guidelines from your supplier for usage rates in soap or IFRA’s category number 9A. If you don't know them or don't see it posted, contact your supplier by phone or email. If your supplier is unable to provide this information or will not provide this information to you, consider finding another supplier and discontinuing the use of the product. This lack of upfront information likely means that the product has not been tested for safety and efficacy and does not adhere to IFRA standards. The last thing you want as a soap maker is to cause harm due to a lack of clear and safe information. (Additionally, do not use fragrance or essential oil suppliers that recommend their product be used in “drops” per measurement, as per the same reasoning above)

  9. Soaping Misinformation: Whole flowers, herbs, full oats, and dried fruits make excellent soap additives and colorants If you take a look at many of the beautiful soaps found on popular blogs, Instagram, and in YouTube/Tiktok tutorials, you will find that many of them use large pieces of flowers, herbs, oats, dried fruits, and other types of additives that create a beautiful and unique looking product. Unfortunately, these types of additives come with risks and are best avoided or placed in a location where they do not remain on the soap during use (such as a decorative top or are easily removed). These types of additives are common in cold process, hot process, and melt and pour products and can cause complications such as discoloration, oxidation, and microbial contamination. One of the most common additives that represent this concern is the use of dried lavender buds. While they may appear a beautifulitufl purple and green before adding to soap, lavender buds oxidize and turn brown, also discoloring any soap that they touch. The same applies to most other florals such as rosebuds. Attempting to use certain organic materials such as strawberries, blueberries, brightly colored flowers, and more in hopes to color a soap will often end in disappointment because many of these have naturally occurring pigments that oxidize and/or react with heat or the highly alkaline solution, also resulting in discoloration and disappointment. When large quantities or sizes of organic materials are added to soap, in addition to discoloration and oxidation, they can also become susceptible to microbial growth and reproduction, especially when wet. Microbes require water for growth and reproduction, and when the soaps are hydrated during use and then stored in a humid, warm, and wet environment where microbial growth is very common, microbial contamination may occur. Imagine what would happen if you placed dried fruit (such as orange slices, which are very common) or a handful of rosebuds or oats in a wet corner of a shower and left them. Microbes would likely find them as excellent hosts. Not all those who use soap know the importance of placing the soap on a soap dish to completely dry in between uses. If you wish to use these types of additives, it is best to place them in a location that they can easily be removed before or during the first use, such as a decorative top, or to reduce their size so that they are included as a powder. Most organic additives like flowers and herbs will brown and discolor, so be sure to keep this in mind during your design process.

  10. Soaping Misinformation: All recipes can be made by hot process or cold process without change or complications We are firm believers in formulating your recipe specifically for the process that you will be using to create your soap. While the base portion of many recipes can be easily used for both hot and cold process, this is certainly not the case for all recipes. For example, most hot process recipes will benefit from a much higher water concentration and it is recommended to use 38%TOW, which is very different from the 25-33%TOW recommended for cold process. Additionally, certain formulas and additives that may be included for one specific process, might hinder the other methodology. For example, if you have a hot process formula that uses 10% stearic acid, 5%TOW sugar, and has a post cook superfat, this would cause all sorts of complications if you did not adapt it for the cold process methodology. The stearic acid will rapidly accelerate the reaction rate and possibly seize the mixture, the sugar would also accelerate the reaction rate and could cause issues like heat tunneling, and the post cook superfat would need to be added at the beginning, as cold process methodologies do not allow for fats to be added post saponification. You can certainly use similar formulas to produce a similar final product, but in our opinion, it is best to formulate your recipe for the specific process you will be using. For many recipes, this might be simply adjusting the water content. But for some recipes, it may be adjusting more than just water and these changes should be carefully considered before starting in order to avoid any unnecessary and unwanted complications.

  11. Soaping Misinformation: Recipes that are provided in reputable resources like popular soap making blogs and books are quality recipes and have correct measurements Because humans are susceptible to mistakes, we can’t assume that all information provided is correct. This is true even when it comes to recipes provided on popular blogs, books, and other resources. It is so easy to mistype a number when publishing a recipe, and just one tiny mistake can completely ruin a formula or create a soap that is dangerous and unsafe for use. I have personally made a typing error in a published recipe before and if it was made according to the printed recipe, it would have resulted in a lye heavy soap. Thank goodness we repeatedly teach all of our students to run each and every recipe through a soap calculator prior to making it in order to check for any errors or discrepancies, and also to make sure that the fatty acid content and predicted soap qualities are ones that you are actually seeking. Because we teach this, the error was found by a student right away and we were able to correct it. Unfortunately, not all those who publish are as lucky as we are to have such wonderful students, so always be sure to follow the above advice to ensure your formula will have the desired properties and create a safe product!

  12. Soaping Misinformation: Liquid soap does not require a preservative because the pH is too high. Many soap makers and resources report that liquid soap (diluted, not paste) does not require a preservative because the pH of soap is simply too high to allow for any microbial growth or contamination. Unfortunately, this is simply not true. There are plenty of microbes that can grow at higher pH levels, some of which are pathogenic and can cause and spread disease. Liquid soap provides the water availability for both the growth and reproduction of microbes and we believe that all liquid soap can benefit from a preservative. Because this topic is so extensive, we have covered it in full detail in this blog post here.


The above list is certainly not an extensive list, and while there are many more that could be added, these are some of the top things we have learned and seen over the course of our soap making careers. If you are interested in learning more about the topics explored above or are interested in learning the fundamentals of soap science, recipe formulating, methodology, troubleshooting, and design, be sure to check out our bookstore today!