Making Soap
On this page I'll provide some information and recipes for making your own soap. I've made three 8 pound batches so far, and all have turned out very well. Homemade soap is inexpensive, and can be made to satisfy whatever requirements you have for a good bar of soap -- scents, additives, harness, lather and many other characteristics can be easily manipulated. Below I'll go through the process. Check out these books on the subject of making your own soap, they are excellent:
- Ann Bramson. 1975. Soap: Making it, Enjoying it. Second Edition. Workman Publishing Company, New York. Simple recipes for mostly tallow- (rendered beef fat) based recipes.
- Susan Miller Cavitch. 1995. The Natural Soap Book: Making Herbal and Vegetable-Based Soaps. Storey Publishing, Pownal, Vermont. A multitude of vegetable-oil based recipes, along with excellent discussions of the chemical process involved in making soaps. Includes useful tables for formulating your own recipes based on the chemical composition of various oils, and chapters on additives, scents and soap characteristics.
Note that making soap involves chemical agents that generate high temperatures and are very caustic -- proceed * at your own risk! *
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Equipment
- A good scale that can measure weights of at least ten pounds, but is also accurate enough to weigh individual ounces. Two scales are best -- one for weights under a pound and one for weights over a pound. Note that all of the main ingredients in the recipes are measured by weight, * not * volume. Any exceptions will be noted in the recipe.
- Tempered glass container for the lye solution. Mixing the lye crystals and water generates heat, so the container you use must be able to tolerate temperatures in excess of 200 degrees F. I use a glass bottle that once held fruit juice because the juice is sterilized at high temperatures in the bottle when they produce it. Other good choices include Pyrex containers, ceramic-coated metal, or stainless steel. The lye solution will eat away at most other substances. You'll also need to be able to pour the lye solution in a slow even stream from your container (without spilling any!!), so make sure this is possible before starting. I punched two small holes in the lid of the fruit juice bottle.
- Spoon made of wood, glass, or stainless steel for stirring solutions. Lye will react with the wood, but not enough to permanently damage it, although wood is harder to clean so you may want to consider keeping a wooden spoon just for this purpose.
- Thermometer with a range of at least 70 - 200 degrees F and graduations down to at least 5 degrees. Two identical thermometers makes things even easier, but this is not necessary.
- Large pot for rendering fats, melting fats and oils and for making soap. Again, the pot should be either glass, ceramic coated or stainless steel, because the lye will react with metals like aluminum, cast iron, copper and will destroy Teflon and other non-stick coatings. I use an 8-quart stainless steel pot).
- Mold for the soap. I used the bottom of a 12-pack Hamms carton lined with a plastic garbage bag. The soap solution will be liquid enough to seep through even small holes, and the plastic makes removing the soap from the mold much easier. Make sure the containter you choose is large enough to hold all the soap, and that you have completely lined it with plastic.
- Blankets or a styrofoam container to insulate the soap as it sets.
Ingredients
- Tallow - recipes that call for tallow are referring to rendered beef fat. The advantage of this ingredient is that it is quite cheap, and if it is in sufficient quantities (like in the Castille Soap recipe below), the soap you make will actually be cheaper than buying soap in the store. The disadvantage is that you must first render the beef fat into tallow -- a disgusting process that takes several hours. Rendering results in about half as much tallow as you started with in beef fat, so double the amount of tallow the recipe calls for when you are buying beef fat. Beef fat can usually be purchased from your butcher. It make take several days for him or her to accumulate enough fat for your recipe, so ask in advance. Here are the steps in rendering beef fat:
- Cut the fat into small chunks - the smaller they are the faster it will render
- Pour a few inches of water into a large pot and add a few tablespoons of salt
- The salt solution causes the proteins to settle on the bottom of the pot, resulting in cleaner tallow
- Heat the water on high, and begin adding the fat chunks as you are cutting them up
- Bring the mixture of fat and salt solution to a boil
- When the fat begins to rise to the surface, lower the heat to a low boil
- Stir occasionally
- After several hours on a low boil, you will have rendered most of the fat. The longer you cook it the more tallow you will produce, but I've never gone for more than 4 hours
- Strain off the remaining solids (crackle) and keep the liquid tallow in a large bowl. Throw the solids away. You can get more tallow if you squeeze the crackle, but this is pretty gross
- Refridgerate the bowl of liquid tallow overnight, covered
- Upon cooling the fat will form three layers - tallow on top, greyish fat in the middle, and protein/water on the bottom (which may have formed a jelly)
- Lift the tallow from the bowl and scrape off the greyish fat and jelly. You should now have an evenly colored, whitish chunk of tallow. It will keep in the fridge for a few months, and lasts a long time if frozen in a sealed container
- Oils - these are the other major constituants of soap. Remember to measure them by weight, not volume.
- Lye - you need to purchase pure lye (Sodium hydroxide), which is usually placed next to the Draino in the supermarket. I've always found lye in the plastic Red Devil cans, but there may be other brands. Don't use Draino, as it does not contain pure lye.
- Water - Any water will do, but distilled water is best because it eliminates the potential for additional chemical effects due to the substances that may be dissolved in regular tap water. If your water is reasonably pure and doesn't contain a lot of sodium bicarbonate, feel free to use it. Otherwise, purchase distilled water. Again, you must measure the water by weight, not volume. One gallon of water weights approximately eight pounds.
- Essential oils - I use a very small amount of these to give my soap a hint of aroma. Don't expect the soap to smell exactly like the oil does because the essential oil will react with the lye just like the other oils, and the aroma is often slightly changed. I normally use a half an ounce (liquid measure), but if you unsure, add less rather than more. A half an ounce in eight pounds of soap is pretty subtle. Essential oils are added just before pouring into the molds and stirred gently into the setting soap.
- Other ingredients - I put about a third of a cup of oatmeal in my soap because I like the texture and it is supposed to give some exfoliating qualities. It, like the essential oils, is added just before pouring into the molds. Do not cook the oatmeal first -- put it in raw.
Directions
Before I begin describing the procedure, I must once again warn you that there are very dangerous chemicals involved in making soap. The lye solution is very caustic, and generates a lot of heat when forming. Be extremely careful of eyes, skin, children, pets, counters and anything else that you don't want to become severely burned. If you are careful, everything will be fine. Proceed at your own risk!
- Clean up your work space, put on your safety goggles, gloves and apron. Close off the room from pets or children, make sure you are sober and keep on your toes
- To weigh the solutions and solids in the recipes use the following method:
- Place the pot or bottle on the scale and note the weight
- Add the intended weight from the recipe to the weight of the pot or bottle
- Begin adding the solution or solids to the container on the scale, stopping when the weight reads the value you calculated in step two. In other words, the scale should read the weight of the container and the weight of the solution or solids you added. To add solids, like tallow, start with large chunks, and as the weight gets close to the final value, add smaller and smaller pieces.
- It is critical that you measure the weights accurately because the chemical reaction depends on a specific ratio of lye to oils. Too much lye and there will be lye left in the soap, too little lye and there will be oils left over.
- Fill the container with water up to the specified weight, and then begin adding lye to the water until you reach the correct final weight. Don't trust the weight on the bottle of lye. Keep in mind that this reaction generates head, and the lye solution will be hotter than 200 degrees when you are finished. Also note that the lye solution is very caustic so handle it with extreme care.
- Remove the bottle from the scale with oven mitts (it will be HOT!), gently stir the solution to dissolve all the lye, and set aside to cool.
- While the lye solution cools, add the fats to your soap pot using the same weighing method discussed above.
- Slowly heat the fats over a low flame.
- When most of the fats have dissolved, remove the pot from the heat and stir until the rest of the solids have dissolved.
- Allow the lye solution AND the fat solution to reach the same temperature, both between 95 and 98 degrees. Heat either if necessary, or cool in a water bath until both solutions at rest are the same temperature. If you use heat or a cooling bath, be sure to let the solutions sit for several minutes away from the heat or cold to insure you have a good temperature reading.
- When the two solutions are at the same temperature, screw the cap on the lye solution bottle.
- Slowly and evenly, pour the lye solution in the fats, while stirring the solution vigorously (but don't beat the solution, just stir quickly).
- Contiue stirring until the mixture becomes thick enough that drops of the solution persist on the surface for several seconds (called tracking). It will be about the consistancy of a thick soup. This may take as long as an hour and a half and may not even thicken totally after that period. Do not worry, but stick with it.
- After an hour and a half of stirring (or if the solution is thick enough before that), add the additional ingredients and stir them into the liquid soap.
- Pour the mixture into the mold.
- Cover the mold in blankets or place the mold in a styrofoam container.
- Let the soap rest for 24 hours.
- After 24 hours the soap will have hardened and can be carefully removed from the mold.
- Once removed, let the giant block of soap sit undisturbed for two weeks or more until the soap is fully hardened.
- If you are making harder soaps (which the two recipes below are), the large block should be cut into bar-sized pieces once the block is hard enough -- usually after two days. It is hard enough when you can cut through it and the bars will hold their shape, even though you can make depressions in the soap. I use a piece of dental floss to cut my bars, but you could use a knife as well. Again, let the bars sit for at least two weeks before using them.
- Rinse the new bars in water to remove the powderly soda ash on the surface.
- Wash!
Recipes
- Castille Soap -- Hard, cheap, with a marginal lather
- 26 ounces Olive oil
- 60 ounces Tallow
- 11 ounces Lye
- 32 ounces Water
- 1/3 cup oatmeal
- 1/2 ounce (liquid measure) essential oil
- All measurements, except where indicated, are * by weight *
- Vegetable Oil Soap -- Hard, more expensive, excellent lather
- 55 ounces Olive oil
- 28 ounces Coconut oil
- 11 ounces Lye
- 31 ounces Water
- 1/3 cup oatmeal
- 1/2 ounce (liquid measure) essential oil
- All measurements, except where indicated, are * by weight *