Soap Making Terms and Tools

Reader Contribution by Julia Shewchuk and Serenity Acres Farm
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Hopefully, after reading 7 Myths and One Truth about Soap Making, you either got curious about soap making or found your passion again. But, as with any skill, there is a little base knowledge you need to successfully follow a recipe.

First we will begin with some of the most commonly used soaping terms found in recipes. After that, I have compiled a list of the more essential tools and ingredients you will need. This way, when I guide you through the recipe in the next blog, you will have everything on hand.

I have listed the soaping terms in alphabetical order for easy look-up. If you are interested in delving deeper into this subject you can find more information at and among others.


Alkali. Sodium Hydroxide a/k/a Lye is an alkali. It is a substance (in soap making it is also called a base) with a PH greater than 7.

Base Oils. Oils or fats such as olive oil, palm oil, coconut oil, sunflower oil, lard and others which are used to mix with your lye solution and which react with the lye to make soap.

Cold Process Method. A simple method of soap making that only requires heat to melt the base oils unless they already are liquid at room temperature such as Olive Oil.  You do not have to cook anything or put anything into the oven. The only heat generated is that during the saponification process when the lye reacts with the base oils. This reaction generating heat is also called an exothermic reaction.

Curing. After the milk soap has saponified and has been cut into loaves and bars, it needs to rest (cure) for a minimum of 4 weeks. Water based soaps don’t need quite as long. This resting time allows the soap to dry and harden for a longer lasting soap.

Essential Oil. A fragrant oil that has been obtained from a plant for its scent, flavor or therapeutic properties.

Fragrance Oil. These are synthetic imitations of essential oils and other scents. Look for phthalate free and paraben free fragrance oils. Phthalates are a group of chemicals used to soften and increase the flexibility of plastic and vinyl. Parabens are the most widely used preservatives in personal care products; however there is growing concern that they might be linked to breast cancer incidents.

Gelling. Once the base oils have started to react and combine with the lye (saponified), the soap batter will begin to heat up. This happens as it reaches trace, continues while the batter is poured into the mold, and for up to 48 hours afterwards. When the soap reaches a temperature hot enough, it will undergo a change, it will gel. It will become translucent and very soft. At this point the soap batter is still very caustic so do not touch it under any circumstances without gloves. Most water based soaps are supposed to gel, many soap makers do not like their milk soaps to gel as the soaps stay a lighter color if they do not gel, but either way the soap is fine and perfectly useable. I for one do not mind if my milk soap gels.

Glycerin. Glycerin is a byproduct of the saponification (turning into soap) process. When the lye and oil/fat molecules grab onto each other to create soap, a glycerin molecule is released. Handcrafted soap contains the glycerin, commercial bars do not. In commercial bars the glycerin has been removed to be used as a valuable moisturizing element in cosmetics. The presence of glycerin in handcrafted soap is what makes those soaps so much more moisturizing and less drying.

Lye Discount. Lye discount means that you are using less lye in the soap recipe than is needed to turn all of your base oils into soap. Most soap recipes recommend using about 5 to 8% less lye than oils. This is done for safety so that a small error in measurement does not create soap with too much lye (lye heavy). This would be very drying to your skin. Way too much lye could have some unintended chemical reactions including something that is called a volcano. A volcano is fascinating to watch, but a horrendous mess to clean up. Lye discount usually also means that there is extra oil left over in each soap bar (not visible as it is such a small amount), which adds to the moisturizing effect of the soap. The term “to super fat” means something very similar, only it refers to the extra amount of oil compared to the amount of lye, and in many cases the terms of lye discount and super fat are exchangeable.

Lye Calculator. A soap making calculator is often called lye calculator, since the main purpose is to calculate the amount of lye needed to achieve full saponification. It calculates the amount of base oils, fragrances, liquid and gives you lots of other valuable information about your soap. Always test a new recipe with a soap calculator. Don’t just take the author’s word for it.

M & P. Melt & Pour refers to the soap kits that I mentioned earlier in the blog. These are pre-made soaps (originally using lye), which just need to be melted and repoured into molds. This is a good soap making starter for kids since the lye has already reacted with the oils and is no longer caustic. Adult supervision is still strongly suggested due to the melting process.

Melting Point. This is the temperature at which the base oils become liquid. Olive oil for example is always liquid, 76 degree Coconut Oil starts melting at 76 degrees Fahrenheit and Palm Oil starts melting at about 95 degrees Fahrenheit. Each oil has its own melting point. Palm Oil also has the unique characteristic that it must be stirred well after melting since its components separate and if not stirred you will have Palm Oil misbehaving and it will bomb your soap.

pH. This is a really important term for soap making. pH is the measure of the acidity or alkalinity of a solution. A substance with a pH value greater than 7.0 (alkaline) is a base; with less than 7.0 (acidic) is an acid; and a pH of 7.0 is neutral. Your skin has a pH of around 7.0. Goats Milk has a pH of around 7.0, which makes it such a favorite and gentle ingredient in handcrafted soaps and why so many people with sensitive skin are able to tolerate goats’ milk soap even if they have trouble with other soaps including other handcrafted ones.

Ricing. This is a dreaded word and experience, however I’ve only ever experienced it once and that was with a water-based soaps and it was a fragrance oil. The soap batter will resemble rice pudding and looks like it has little rice grains in it.  It was a small batch and it still looked presentable at the end.

Saponification. This is a term you will hear and use often. Saponification is the exothermic (creates heat) chemical reaction between the alkali (lye) and your base oils or fat (lard) to create soap and lasts about 24 – 48 hours. In simple terms: one lye molecule combines with one fat/oil molecule and turns into one soap molecule while generating one extra glycerin molecule.

Seizing. When this happens, it usually means that you bombed your soap. When your soap batter seizes, it has solidified so quickly that it is stuck in the pot or on your stick blender (hence the term “soap on a stick”). It can have different causes, but usually it means there was too much lye or too little base oils due to an error in measurement. Sometimes it can also be caused by a misbehaving fragrance oil, although here soap usually goes to a very heavy trace very quickly and is still salvageable by “globbing” it into the mold.

Soap. You have soap at the end of the saponification process, about 24 – 48 hours after pouring the batter into the mold. Most commercial bars are no longer soaps; they are detergents because they are not created with an alkali or lye. The definition for soap is the reaction of a fat or oils with an alkali. If it was not made with lye, it cannot call itself soap.

Soda Ash. This is a powdery white residue that sometimes forms on the surface of soap. It is just aesthetic and can be wiped off with a damp cloth. It is a sign of a handmade soap and I don’t worry about it if it occurs. I found it happens more on small batches than on larger batches.

Sodium Hydroxide. This is just another word for lye, the alkali or base in the soap making recipe.

Super-fatting. The excess oils left in the finished soap which have not reacted with the lye during the saponification process. This extra amount is intentional for safety reasons and contributes to the moisturizing qualities of soap. Exchangeable term with lye discount in most cases.

Trace. Trace is everything in making soap. It is the point in soap making where the lye and oil molecules are reacting with each other so they won’t let go again. The temperature rises and the batter begins to thicken so that your stick blender will leave a trace behind when stirring or will leave little indents when drizzling drops onto the surface. There is thin trace, medium trace and heavy trace and each has its place in soap making. The soap is fine to pour at thin trace, this is good for large batches; at medium trace, good for smaller batches or mixing in colors; and at heavy trace, good for layering soap colors for example.

Water Discount. This term means using less liquid (in most cases water, but can be beer, wine, milk, tea or any combination) than the generally recommended safe amount. Any soap/lye calculator will automatically put in 38% as the amount of liquid used as a percentage of the amount of oils used. Less water can be used to create a harder bar, which can be desirable in soaps with a lot of olive oil or soaps that contain clay. Using less liquid is a bit of a gamble because it will speed up the chemical reaction and will not give you quite as much time to mix everything together. Experience will help you here until then it’s probably a good idea to stay with the standard 38%. I have made bars with 30% water just for experimentation and I really didn’t like the feel of them.

Tools and Ingredients

soap mold with a lid. This can be a wooden box, a silicone mold, a (clean!) milk carton, a pvc pipe. For our recipe, the mold should hold 4 pounds of soap batter.
freezer paper. This is the liner for the mold. Shiny side out.
gallon freezer bags. These are to store 16 oz of frozen goat milk.
disposable or long plastic gloves to protect your hands when mixing lye.
safety glasses to protect your eyes from lye splashes.
immersion stick blender to stir the lye into the base oils and to bring it to trace. Hand stirring will take hours.
scissors. Scissors are always handy and used to cut the freezer paper to fit the mold.
accurate scale to measure the ingredients exactly.
silicone spatulas (2), one for the oil and one for the lye. I don’t use wooden spoons because the lye eats the wood.
small glass measuring cup for the essential oils. Easy to clean and some essential oils eat right through the plastic.
medium to large measuring cups for the lye/milk mixture.
stainless steel pot for the soap batter (no aluminum). A large glass container such as Pyrex would also work.
thermometer to measure the temperature of oils, milk and soap batter. I use a laser thermometer, but a glass or stainless steel candy thermometer will also work.
sour cream or similar plastic container to measure out the lye.
old cookie tray or something similar to store the soaps after cutting them into bars
large knife for cutting the soap into loaves and bars.
newspaper to cover your work area and the floor J (you never know).
recipe to follow and a pen to write notes.
tape to tape the liner to the mold.
towels to wrap the molds.
an apron and old clothes.


frozen goat’s milk in a freezer bag.
food grade lye powder
pure or grade-A olive oil
coconut oil 76 Degrees
palm oil (organic sustainable)
essential or fragrance oil suitable for cold process soap making (not candle making)

Note: Running water to neutralize lye burns. And here is another semi myth: to use a small splash of Vinegar to neutralize a lye burn. While vinegar does that if used in sufficient quantities, you would need to rinse the lye burn for 15 minutes with vinegar to get enough of the vinegar liquid to neutralize the burn and get the lye off your skin. If you don’t use enough vinegar, the vinegar will react with the lye and add a heat burn to your lye burn. Sufficient quantities of running water are much more readily available: just flush your skin for 15 minutes under the faucet. This is easier and much more realistic and accomplishes the same thing, removing the lye from your skin. If a lye burn is more extensive or in the eyes – call 911 immediately, and keep rinsing the lye burn with water if possible, until professional medical help arrives.

 Looking forward to continuing this journey with you. If you are curious to find out more about our farm, here is a great little video shot by film students from West Palm Beach in Florida. Julia

Julia Shewchuk owns and operates Serenity Acres Farm on 80 acres in Florida. Serenity Acres runs on solar, is Animal Welfare Approved-certified, host to  WWOOFers, and is the home to  dairy goats, 12 Black Angus cattle, 100 laying hens, 3 horses, 2 cats, 5 house dogs, 8 livestock guardian dogs, and 2 ducks. Read all of Julia’s MOTHER EARTH NEWS posts here.

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