Today's blog will expand and deepen your current knowledge about an item that you use everyday… well at least I hope you do! In particular, I plan to provide you with the history, the science and the know how to make your very own bar of soap!
This is a relatively new passion of mine – no not the use of soap, I assure you I’ve been using soap for years, however, an excess amount of goat’s milk in my fridge and a desire to do something other than make more cheese, led me into the ancient art of soap making.
History
Soap making is old, very old, with some of the first “recipes” dating back to the second century Essentially the first soaps were a mixture of fats and ashes that made a rather disgusting gelatin mixture that one rubbed all over themselves. There is an interesting legend surrounding the discovery of soap making. The legend says soap was first discovered by women washing clothes along the Tiber River at the bottom of Sapo Hill. The women noticed the their clothes became cleaner with far less effort at that particular location. What was happening? The ashes and the grease of animals from the sacrificial fires of the temples situated on the top of Sapo Hill mixed with the rain, making soap which ran down the slope in the streams of rain water giving the women a wash day bonus. You will see that saponification, the chemical name for the soap making reaction, bears the name of that hill in Rome long ago. Whether this legend is indeed true or not it is likely that the first soaps were accidentally made by fat dripping into the ashes of cooking fires. As you will see, that process contains all the necessary ingredients for the chemical process of making soap!
Chemical Process
Saponification is a very big chemical word for the rather complex but easy reaction that creates soap. Saponification is what happens when a base meets an acid or when lye mixes with fat. When fats or oils, which contain fatty acids are mixed with a strong alkali – like lye, the alkali first splits the fats or oils into their two major parts fatty acids and glycerin. After this splitting of the fats or oils, the sodium or potassium part of the alkali joins with the fatty acid part of the fat or oils. This makes soap.
An interesting fact to know is when soap is properly made and cured, the soap no longer contains lye, as the chemical reaction has converted the alkali (lye), water, oils, and fats into saponified oils, fats, and glycerin (soap).
How to make it
So now that you have a bit of information on the chemical process of making soap, how do you actually make soap!?
Essentially there are two ways – cold process or hot process.
In both cold-process and hot-process soapmaking, heat is required for saponification. One just uses more and therefore is quicker.
Hot-process soapmaking was used frequently in the past when the purity of lye was unreliable, and this process can use natural lye solutions, such as potash. The main benefit of hot processing is that the exact concentration of the lye solution does not need to be known to perform the process with success.
Given that the cold process method is the one that I am most familiar with, is the safest and easiest to do in your home kitchen, I thought I would briefly describe how one would make soap in this way!
To start you need a recipe that has already taken into consideration the exact fat to lye ratio that is required to ensure that that saponification occurs correctly. Otherwise you need to look up the saponification value of the fats being used on a saponification chart, which is then used to calculate the appropriate amount of lye. I just use a recipe, its easier.
The lye is dissolved in water or milk. In my case, fresh goats milk! Then oils are heated, or melted if they are solid at room temperature. Once both substances have cooled to approximately 100-110 °F (37-43 °C), and are no more than 10°F (~5.5°C) apart, they may be combined. This lye-fat mixture is stirred until "trace" (modern-day amateur soapmakers often use a stick blender to speed this process). After much stirring, the mixture turns to the consistency of a cake batter. Trace has occurred if you drizzle a bit of soap on the top of the mixture, it should take some time before sinking back in to the rest of the mixture. Essential oils, fragrance oils, botanicals, herbs, oatmeal or other additives are added at this time.
The batch is then poured into molds, and left to continue saponification for 18 to 48 hours. Once the soap is firm enough it can be removed from the mold and cut into bars. Cold-process soaps are typically cured and hardened on a drying rack for 2–6 weeks before use.
So while soap making is fairly easy, a note of caution is advisable… Soap contains lye. Lye will burn your skin and blind you if it splashes in your eyes. Vinegar is an antidote, but it cannot undo the damage of spilled lye simply halt further damage. One should use gloves, goggles, long sleeves and make sure children are not around when handling lye.
As I told you, handmade soap contains the natural forming ingredient glycerin. In order to make the extremely hard French Milled soaps, the glycerin must be removed or the soap would be too soft. More glycerin may be added later, but never at the original level of the soap making process. One could extract the glycerin if you wished when making soap at home by sprinkling salt on the soap. The salt causes the soap to curdle and float to the top. After skimming off the soap, you are left with glycerin. So now you know that there is no such thing as 100% glycerin soap!
Make certain you purchase soap from a soap maker or company that discloses the list of ingredients on the package. Soap is sometimes considered a cosmetic and must be labeled by FDA standards and sometimes it is not - and no ingredients are required.
Most of the commercial soap bars that line typical grocery store shelves are actually synthetic detergents.
So as you grab the soap in the shower tomorrow, I trust you will look at this slippery friend, with a bit more knowledge and respect. And I hope I’ve peaked your interest just a bit into perhaps trying your hand at making your own someday!
