Making SoapMar 02, 2020
Soap is used to wash many things, such as dishes or clothes, and in all cases it acts in the same way. It works as something called a surfactant, which emulsifies oils and allows water to carry them away. Historically,
soapwas made using a combination of rainwater, animal fats or vegetable oils, and ash. Over thousands of years, the process was slowly perfected and the main ingredient in the ashes was eventually discovered to be base. For a long time, all
soaps were solids, and it wasn't until 1865 that a man named William Sheppard patented a liquid version. From then on, more and more liquid type soaps were developed, and now we have a wide variety of different options.
The invention of a proper liquid form of soap was actually a big deal, because it made things like floors and clothes much easier to clean. Soap is derived from triglycerides, which are the fat storage molecules used by almost all plants and animals. Animal fats and vegetable oils are almost pure triglycerides. There are two main parts of the triglyceride molecule: the glycerol backbone and the fatty acid tails. An ester link connects the tails to the backbone and is a relatively sensitive link. When triglycerides are treated with a strong base such as sodium hydroxide, they undergo a saponification reaction.
This leads to the breaking of the ester bond and the formation of glycerol and fatty acid salts. Desalted fatty acids are pretty much what soap is. One end has strong charge separation that makes it polar, while the long tail of the carbon chain is nonpolar. The polar end is hydrophilic, which literally means it loves water, and the chain is lipophilic, which means it loves fat. In general, nonpolar molecules dissolve in nonpolar liquids like oils, and polar molecules dissolve in polar liquids like water. Because this molecule has both properties, it acts as a sort of bridge between oil and water.
When soap is mixed with water, the molecules organize themselves into spherical structures called micelles. The hydrophilic and polar heads are on the outside in contact with water and the non-polar tails are protected on the inside. Technically, micelles do not dissolve in water and exist as a colloid, which is a very finely dispersed suspension. If oil is present, the micelles can collect and retain a small droplet within their nonpolar interior. The tails inside dissolve in the oil and the entire drop is protected from water. The polar heads give the surface a negative charge that helps repel other micelles.
This prevents the oil from coalescing and keeps it separated as very small, stabilized droplets. When it comes to
makingsoap, it can be surprisingly tricky. It always involves basic hydrolysis of triglycerides, but the ingredients and process differ quite a bit. Depending on the base used and the source of the triglycerides, the final soap can have very different properties. With fatty acids, the most important characteristic is the length of the chain. As the chain length increases, it becomes less polar and therefore less soluble in water. Long-chain fatty acid soaps also tend to be harsher and don't lather as easily.
The base that is used will influence the fatty acid salt that is obtained in the end. For example: with sodium hydroxide we obtain sodium salt fatty acids, which tend to be harder and less soluble. Potassium hydroxide forms much softer, water-soluble salts, which is why it is the base used to make liquid soaps. It's not as common, but lithium hydroxide can also be used to make lithium soap. However, this soap is not meant to clean things; it is usually dispersed in an oil to form a thick lubricating grease. It is non-corrosive, adheres well to metal, and is used to lubricate many household products.
Soap can be made by two main processes: one hot and one cold. The hot one is done around 90°C, and the cold one is close to room temperature. The main benefits of the cold process is that it is easily molded into many different shapes and is compatible with a wide range of additives. The main drawback is that it typically takes four to six weeks to cure before it can be used. The benefit of the hot process is that it is fast and only takes about a day to cure. However, it is very thick and can only be molded into very basic shapes.
Also, because it needs to be heated, many additives are not compatible. For this video, I've decided to cover both processes, and I'll be
makingsolid and liquid soap. However, there is a lot to cover, so I have divided it into two videos. For this one, I'll make solid soap by the cold process; and in the second part, I will make liquid soap by the hot process. Ok, to make the solid soap, I'm going to need three main things: olive oil, coconut oil, and sodium hydroxide. It is also possible to use other oils such as sunflower oil or almond oil, and the properties of the oil you choose will change the characteristics of the final soap.
At the store, there are a few types of olive oils you can buy, but when it comes to making soap, it doesn't really matter too much. On the right, I have all the additives that I plan to put in the soap. With cold process we can use a lot of different additives, and I'm going to add things like lavender, cinnamon oil, and maple brown. One thing I want you to remember is that making soap is just like cooking, and there are many different things you can do. The recipe I'm following is just one of thousands, and if you decide to try it yourself, don't feel like you need to do exactly what I do.
I highly recommend you do some searching online and find the recipe that suits you best. To start, I need to make a sodium hydroxide solution, so I measure 200 milliliters of distilled water. Then I weighed out about 80 grams of sodium hydroxide. Sodium hydroxide is a strong base, so care must be taken when working with it. However, unlike what was shown in Fight Club, touching it will not melt your skin. If it does get on your skin or hand, just remove it quickly and, just in case, wash it off with plenty of water. Anyway, now is the time to dissolve the sodium hydroxide, and this is where the real danger comes in.
Unlike the solid form, a sodium hydroxide solution is much more corrosive. Also, dissolving sodium hydroxide generates a lot of heat and the solution will get quite hot. You can notice here that I don't wear gloves yet, and this is because putting it on your skin isn't too bad yet. However, if you were to accidentally splash some in your eyes, it could quickly do major damage and potentially blind you. So for this step, some form of eye protection such as goggles is an absolute must. You can also wear something like a lab coat to protect your clothing if you're worried about damaging it.
Just to show you that it's not the end of the world to put it on your skin, I dipped my finger on purpose. After doing this, I just washed my hand with some water, and there was absolutely no irritation or anything. Anyway, all the sodium hydroxide eventually dissolves, but the solution is still pretty hot, so I temporarily set it aside to cool and prepare the oils in the meantime. So, for the olive oil, I need 500 grams and I simply weigh it with a kitchen scale. When I'm done, I set it aside and move on to the coconut oil.
The oil is solid so I have to scoop it out with a spoon. When I finish weighing one hundred grams I put it in the microwave. Coconut oil's melting point is only slightly above room temperature, so it doesn't take a lot of heat to melt it completely. The now liquid coconut oil is then mixed with the olive oil and stirred well. To the oil mixture I add the sodium hydroxide solution from earlier. By the time it is added, we can already see some turbidity, which is the start of the reaction. Using a spoon, I give it a quick mix and then follow with a hand mixer.
Before I start, I cover the top with some plastic wrap to try to prevent splatter. However, if you are going to make soap by the cold process, I suggest investing in a hand blender. I think this was only like ten bucks or something. It is definitely possible to do it manually, but it takes much longer. Ok, so what we have here is known as a saponification reaction. The ester bonds in the triglycerides of olive and coconut oil hydrolyze, forming salty fatty acids and glycerol. Mechanistically, we start with a hydroxide ion attack that opens the carbonyl. Electrons from oxygen moved to reform the double bond, and the carbon-oxygen bond between the fatty acid and glycerol was broken.
The negative oxygen charge from the glycerol then picks up the acidic hydrogen from the fatty acid. This reaction is repeated two more times to completely remove the glycerol backbone. When making hard soaps, it is very important to use slightly less sodium hydroxide than is necessary to fully saponify all of the oil. The sodium hydroxide is consumed in the reaction and we want little or none to remain at the end. Otherwise, it can sometimes be irritating to the skin. Also, leaving a little extra oil in the soap will make it softer on the hands and less dehydrating.
This idea of using more oil than necessary is generally known as superoiling. Because this is all done cold, the reaction is quite slow, taking around two weeks to complete. It is then left for another four weeks for the extra water to evaporate, helping to harden the soap. With very little mixing, it really doesn't take long to get to a stage called a "trace". At the trace point, we have a stable emulsion and the oil will no longer separate. However, the soap can still be quite thin at this point, and if we keep mixing things up, it will thicken up.
There is no real perfect thickness to go for, and it really depends on the person making the soap. There are some people who like to stop when it's very watery and thin, and others who like to keep going until it's pretty thick. From what I read, the point at which you stop doesn't really affect cure time or anything, and mostly just affects layout possibilities. The light trail is very runny and seems to be the best for doing spiral designs. It is also an ideal place to put liquid additives because they will mix very easily. The medium trail is good for adding solid things like poppy seeds or coffee grounds because it's still easy to mix, but they'll stay suspended in it.
The thick line is quite slimy and holds its shape when handled, so it's really good for making textured designs. It's also good if you want to make multi-layered soap. I'm not doing anything fancy anyway, and just kept going to a medium trail. I chose to go to this point because I need to mix liquid and solid additives, and I can do it all in one batch. I wanted to make seven different types of soap, so I transferred almost everything to separate beakers. I tried to put an equal amount on each but clearly failed. To the first beaker, I added cinnamon essential oil, which is practically pure cinnamaldehyde.
Then using my stir stick I mixed it as best I could. One thing to point out is that I'm not an expert on this, and in each case I think I added too much. When I was done, I quickly marked the glass "cin" for the cinnamaldehyde, then moved on to the next one. For this one, I added bitter almond essential oil, which is pretty much benzaldehyde. Benzaldehyde has a very pleasant almond odor that smells like cherry candies. One of the main reasons additives are added after we reach the trace is because at this point, most of the sodium hydroxide has been consumed.
Certain things, especially cinnamaldehyde and benzaldehyde, are very sensitive to strong bases. If they were added immediately at the beginning, much of it would have reacted with the sodium hydroxide and been destroyed. In the third, I added freshly ground lavender. For the fourth, I used a lot of dark cocoa and the end result looked like a chocolate pudding. In the next one I decided to make a scrub, so I threw in some poppy seeds. I felt that the poppy seeds alone might have been too plain, so I put in a few drops of food coloring. I purposely didn't blend it all the way, so I could get a bit of a swirling color effect.
For the sixth, I melted down a bunch of menthol crystals and dumped them inside. Menthol has a very strong minty smell, and it's kind of the opposite of spicy. Instead of inducing heat, it induces the sensation of cold. For this batch, I added too much, and it's probably going to hurt a lot to use this soap. I thought since it's mint it would make sense to make the soap green. However, after mixing it for a while, it somehow turned orange. Anyway, for the last one I used maple coffee grounds. I mixed it well, and then went back to the first one and added a bunch of red food coloring to make the cinnamon one pink.
Ok, now it's time to mold the soap. And you can buy one or make it yourself. I decided to do it both ways, and justI would make a custom mold. Doing this is pretty easy: I just mix an equal amount of each part and mix it until it's a uniform color. I then squashed it around the bottom of a beaker and included a 3D printed model of the caffeine molecule. When the mold was ready, I removed the beaker and scooped out the plastic molecule. Then, using scissors, I cleaned up the edges, and it's pretty much done.
By the time I started transferring things to the molds, it had already gotten much thicker. One thing to keep in mind though is that every batch is not the same and this is because different additives can affect thickness. So, for example, the first one was cinnamaldehyde, and even though it was thick, it still looked a bit runny. Now with the benzaldehyde, you can see that it's much thicker than before, and it's almost like a paste. Most of the others were relatively runny, except for the menthol which was also a paste. It was a bit of a mess anyway, but I finally transferred everything to the mold.
Using my finger, I wiped it clean, then temporarily set it aside. So now to the mold that I made, I added the coffee one. Using the spoon, I push things down to make sure the molecule is completely filled. So at this point. I was almost done, but apparently I still had a little more soap left in the original container, so I filled another mold. For the third mold I did the same thing as the first bar of soap: I just added cinnamaldehyde and a bunch of red food coloring. I left it overnight and by morning it was pretty hard.
So now that it's a bit cured, it's time to unmold everything. At this point, all the soaps are solid, but they are still relatively soft. While it's still soft, it's a good idea to shape it because it's so easy to cut. If you wait until it's fully healed, it's going to be quite a pain. When I unmolded the smaller Cinnamon Oil Soaps, you can see that they weren't quite ready. As we just saw earlier, additives can affect thickness, so it's not too surprising to see that it could affect cure time as well. And if you don't take this into account, you'll end up demolding soap here like I did, with some falling apart.
Anyway, I went ahead and demolded them all, and you can see that for the most part, they were pretty good; there were only a couple of terrible ones. These were the last to be demolded, and they were pretty easy. Visually alone though, you can see that the cinnamaldehyde and menthols are a bit smoother. Now I have to wait four to six weeks for all the soap to cure. All soap should be turned over at least once a week to ensure it dries properly. This is six weeks later, and at this point, the soap should be done.
All the pieces look pretty much the same, except they're definitely a lot harder than when I started. So now to test the soap and see how well it works. I decided to go with the menthol, because I wanted to see how much of a cooling effect it would have on my hands. Based on the amount I put in, I expected it to burn a bit, but I didn't feel anything at all. So apparently I made a decent bar of soap. Anyway, now that I've successfully made solid soap, I'm going to move on to part two where I'll make the liquid version.
I highly recommend you guys check it out because, well, I mean, at least I think it's interesting. I also do it using the hot process so you can see how it compares to cold. You can find it by clicking the link on the screen or in the description. I originally planned to keep all the soap I made, but at the last second I decided to give most of it away. I'm going to do the same type of promotion that I did in a previous video, where all you need to do to participate is follow me on Twitter, visit my Instagram or subscribe to me on this YouTube channel or the other one.
NiloBlue channel. The link to the contest will be in the description, and this time I'm going with five winners, so the probability will be much higher. Each winner will get a random bar of soap, not including the caffeine one because I want to keep it, or the menthol one because I used it. I will send everything completely free and I will also send it anywhere in the world. And just one last thing The winner of my previous contest, Jou Young, never responded to my email and never contacted me So Jou Young, if you're hearing this, I'll give you another week to contact me either through Twitter or by email.
Otherwise, I'll draw another winner. Thank you very much to all my followers on Patreon: anyone who supports me will see my videos 24 hours before I post them on YouTube, and they will also be able to contact me directly. . Anyone who supports me with five dollars or more will also get her name at the end of the video as seen here. In the last shot of my video here, I want to start including music. I really don't want the typical royalty-free stuff, and I'd rather support some artists with free advertising. So if you're interested, just send me an email or hit me up on Twitter, and if I like what I hear, I'll include you.
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