Over on the Soap Making Forum, lots of people just LOVE salt bars. It took me a while to warm up to the idea - I mistakenly assumed they left your skin feeling like you just spent the day at the beach. All that salt just makes me want to take a shower. What finally made me try a batch was that several members swear by salt bars for their acne. My son has a pretty bad case, especially on his back, so I thought "what the heck, give it a try." Salt bars are often made from 100% coconut oil, which theoretically should dry your skin out like the Sahara Desert. However, if you superfat at least 15% (most seem to superfat 20% with 100% coconut oil bars), that mitigates the drying effects of the oil. The other thing many suggested is to let them cure for at least three months.
I made my first batch of salt bars about 6 weeks ago. My son is here this weekend, but didn't come with any of the his acne meds. So I decided to try one of the salt bars. Wow! The lather is fantastic! Thick, creamy, bubbly, - and lots of it. I'm going to send the bar back with him for his dad and other care-givers to use. Obviously I'll have to report back on whether or not it helped his acne, but it sure was a nice bar of soap. I tried it to wash my hands - it rinses off so cleanly!
The recipe I used was 90% coconut oil, 10% shea butter, 50% of the oil weight in salt, and I used coconut milk instead of water. I superfatted at 18%, assuming that the coconut milk would add some more fat to the mix. Making salt bars is easy. Mix the oil and lye solution as usual, then add the salt at trace. Don't discount the water - use a full 38% of oil weight in water or coconut milk. Salt bars harden fast - you have to take them out of the mold and cut them within a couple of hours, or they will be so hard they'll crumble when you try to cut them. Unless you add color, they will turn out very white. Any FO you use may also change the color.
For my second bath, which I only made a week ago, I bought a standard rectangle silicone mold from Wholesale Supplies Plus - I could not find it anywhere else. I used the same recipe with the exception of upping the salt to 75% of the weight of the oils. I'm interested to see what I think of the difference in salt concentration in the soap. The mold makes some beautiful bars of soap. If you use a log mold and cut the bars, they will look more rustic.
My original batch are the green bars on the left, below:
Here are the bars taken from the silicone mold:
and...
I can't wait to try the second batch.
So go ahead and give salt bars a try!
Saturday, April 30, 2011
Tuesday, April 26, 2011
Commercial Soap - It may not be what you think!
If you are reading this, you probably already believe that handcrafted soap is superior to commercially made soap. But why is that? I won't go into all of the myriad reasons here, but want to focus on one common reason people say commercial soap is not good: it is not really soap, but actually is made of detergents. I heard/read that many times when I first started to make soap, taking it as the truth. But is it? Today I was in a grocery store and decided to look at soap ingredients to see what was really in there. I'm sure I looked odd reading soap labels and writing down my findings. But in the name of serious research, I'm willing to put up with a few strange glances. Surprise! There is a lot more soap in the soap aisle than I was led to believe. However, that doesn't mean it is good soap.
I found several bars that were real soap, not detergents. However, the oils used to make it were universally palm, coconut, palm kernel, and (beef) tallow. Cheap, easy to obtain. But soaps made mostly of palm, coconut, and palm kernel oil are going to be harsh and drying by nature. Their main fatty acids are saturated, which make soaps that clean well - so well they strip the oils we want to keep in our skin as well as the dirt we want to wash off. Ingredients are listed in the order of largest amount to smallest, and it is common to find those oils listed first, or "possibly" first - to give the manufacturer flexibility, they often will list ingredients as X or Y or Z. So whatever they were able to buy most easily or cheapest, that's what goes into the soap. Beef tallow, with it's fatty acid composition, should make a decent soap, but if it the quantity is small enough, it won't mitigate the other, harsher, oils. Not one soap listed olive oil or any of the other oils and butters we tend to use in handcrafted soap as a saponified oil.
Other bars were a combination of detergent and soap, or just detergent. Some people don't want to use detergents because they believe them to be harsh, or even harmful. That is a debatable point, but it is true that detergents are synthesized from petroleum, and I'm of the opinion that any time we can avoid using petroleum derivatives, that's a good thing.
I did a quick search on commercial soap-making methods, and generally speaking, the oils and lye are cooked until saponified, then impurities are removed by salt-water baths. Glycerin is one of the "impurities" that get removed by this process, which contributes to the drying effects of commercial soap. It is interesting to note that glycerin is often added back to commercial soap (just look at the ingredients), but exactly how much is difficult to determine. It is quite possible the amount is too minute to make much of a difference. We do know that the extracted glycerin is often sold, so it stands to reason that there must be less glycerin in the soap than there was originally.
Finally, chelating agents are usually added. These chemicals bind metal ions in the water, which otherwise would combine with some of the soap salts and form soap scum. Citric acid and sodium chloride are often added as chelating agents, but even more popular are tetrasodium EDTA and tetrasodium etidronate. These last two are controversial; you can easily find articles they are unsafe, and just as easily find articles that say they are safe. Questions about the use of citric acid and sodium chloride as chelating agents pop up on the Soap Making Forum every so often. We consume both of those chemical regularly in our food, so putting them in our soap should be just fine.
Bottom line? It isn't correct to say that commercial soap "isn't soap, but made of detergents." However, there are still plenty of reasons why commercial soap is inferior to handcrafted soap, at least IMHO. It's now up to you to decide for yourself.
I found several bars that were real soap, not detergents. However, the oils used to make it were universally palm, coconut, palm kernel, and (beef) tallow. Cheap, easy to obtain. But soaps made mostly of palm, coconut, and palm kernel oil are going to be harsh and drying by nature. Their main fatty acids are saturated, which make soaps that clean well - so well they strip the oils we want to keep in our skin as well as the dirt we want to wash off. Ingredients are listed in the order of largest amount to smallest, and it is common to find those oils listed first, or "possibly" first - to give the manufacturer flexibility, they often will list ingredients as X or Y or Z. So whatever they were able to buy most easily or cheapest, that's what goes into the soap. Beef tallow, with it's fatty acid composition, should make a decent soap, but if it the quantity is small enough, it won't mitigate the other, harsher, oils. Not one soap listed olive oil or any of the other oils and butters we tend to use in handcrafted soap as a saponified oil.
Other bars were a combination of detergent and soap, or just detergent. Some people don't want to use detergents because they believe them to be harsh, or even harmful. That is a debatable point, but it is true that detergents are synthesized from petroleum, and I'm of the opinion that any time we can avoid using petroleum derivatives, that's a good thing.
I did a quick search on commercial soap-making methods, and generally speaking, the oils and lye are cooked until saponified, then impurities are removed by salt-water baths. Glycerin is one of the "impurities" that get removed by this process, which contributes to the drying effects of commercial soap. It is interesting to note that glycerin is often added back to commercial soap (just look at the ingredients), but exactly how much is difficult to determine. It is quite possible the amount is too minute to make much of a difference. We do know that the extracted glycerin is often sold, so it stands to reason that there must be less glycerin in the soap than there was originally.
Finally, chelating agents are usually added. These chemicals bind metal ions in the water, which otherwise would combine with some of the soap salts and form soap scum. Citric acid and sodium chloride are often added as chelating agents, but even more popular are tetrasodium EDTA and tetrasodium etidronate. These last two are controversial; you can easily find articles they are unsafe, and just as easily find articles that say they are safe. Questions about the use of citric acid and sodium chloride as chelating agents pop up on the Soap Making Forum every so often. We consume both of those chemical regularly in our food, so putting them in our soap should be just fine.
Bottom line? It isn't correct to say that commercial soap "isn't soap, but made of detergents." However, there are still plenty of reasons why commercial soap is inferior to handcrafted soap, at least IMHO. It's now up to you to decide for yourself.
Sunday, April 24, 2011
Two for One: Gel and Colloidal Oatmeal
Gel: On the Soap Making Forum, many new members post questions about soap and gel (I did!). Experienced soapers throw the word around, but to a new soapmaker, the term is pretty mysterious. Therefore it makes sense that one of my first posts should be about gel: what it is, why we care, and how to encourage or discourage it from happening.
The chemical reaction between lye and fats is called saponification. This reaction is exothermic - it releases energy in the form of heat. (Some reactions are endothermic, or require energy to occur, and take it out of the environment in the form of heat. Paradoxically, even though heat is being "added" to the reaction, the reactants and products become cooler. This happens when you make ice cream, and add salt to the ice around the ice cream maker. If you checked the temperature of the ice, and then the ice and salt mixture, you would see that the temperature decreases. That's how you get temperatures cold enough to actually freeze the ice cream. Same thing when you put salt on your sidewalk to melt the ice. The temperature of the salt water would be colder than just the ice itself.) But I digress. Depending upon the oils you use, the temperatures you soap at, fragrance oils (FO) you use, and environmental temperatures, the saponification reaction can generate more or less heat. If the reaction gets hot enough, the soap goes through a gel phase. You can see this happening - it starts in the center of the mixture, because that's where it will get hottest first - the forming soap becomes darker and somewhat translucent in appearance. The gel phase will spread outward, sometimes stopping before it reaches the edge, sometimes completely gelling the entire batch. Large batches, and using log molds where the surface area ratio is low compared to the volume of the batch, tend to trap the heat being created by the reaction, encouraging gel to occur. Soap that goes through saponification without getting hot enough to go through a gel phase will be lighter in color and opaque in appearance compared to gelled soap.
Many new soapers ask which is better, gelled or non-gelled soap? The answer is neither, or rather, it depends upon your aesthetic preference. Gelled and non-gelled soap last the same amount of time, have the same lather, and the same properties. The only real difference is in appearance. Gelled soap is darker and has a tiny bit of translucence. Non-gelled soap is significantly lighter and opaque. I made a batch of soap, and put most of it in a log mold, and put the left overs in individual molds. The individual molds did not gel, while the log mold did gel. Here is a picture:
As you can see, the soap on the left is much lighter than the soap on the right, even though it came from the same batch.
The one nemesis with gelling is the dreaded "partial gel". This is where the center of the soap gels, but the edges do not. This results in a soap that is lighter and opaque on the outside, but darker on the inside. Imagine putting a half moon of the soap on the right in the middle of the soap on the left. Not attractive. Because you want to avoid partial gel, most soapers either encourage a full gel, or try to discourage it from happening at all. You can encourage gel in several ways: soap warm and keep the mold in a warm area, turn the oven on to 170 degrees F (76 - 77 degrees C) then turn it off and put your soap mold inside for several hours, or wrap the mold up in towels. I emphasized turn off the oven because if you don't, you could end up with the soap overheating, and a "volcano" eruption. I use a space blanket, which is cheap, easy, and doesn't use any gas or electricity like the oven. It is essentially a large sheet of silver mylar, and you can buy them in the camping sections of places like Target and Wal Mart, and even online at Amazon.com. I lay down a towel, then lay the space blanket on top (it is large, so I double it up). Put my mold on top, fill it, and wrap the blanket and towel over the mold. The soap will often rise in the middle, so I put some wood at the ends of my log mold to keep the space blanket off the top of the soap. I leave everything like that until the next day. Works like a charm. Here are pictures of my set up:
Avoiding gel can be much harder. If you live in a hot and humid place, it can be nearly impossible. Recipes high in some oils, like coconut, can be very difficult to keep from gelling. Suggestions: soap in small batches, use tray molds that spread the batter out, put it in the freezer or refrigerator, and soap cool. I just made a small, 1 lb test batch, put it in the freezer, and it gelled in the freezer! Preventing gel is trickier than ensuring a full gel. But if you absolutely love the creamy look of ungelled soap, you will eventually find what works for you.
Colloidal Oatmeal: I needed some colloidal oatmeal for a facial soap recipe I was testing, but didn't want to pay the high price of ordering it online. I did some Internet research, and my problem was solved.
The reason to use colloidal oatmeal is the particles are small enough that they evenly disperse throughout the soap mixture, so you get the benefit of the soothing quality of the oatmeal in the lather, and you don't get any rough pieces that might scratch your skin. To make it, just take old-fashioned oats (not instant, and I don't use quick-cook either), and put some in a food processor. Grind it up as small as possible. At this stage it is probably okay to use, but colloidal oatmeal is an extremely fine powder, and you probably won't get that with your food processor. Small coffee grinder to the rescue. Put some of the ground oatmeal in the coffee grinder (cleaned, of course), a few pulses, and voila! real colloidal oatmeal. WAY cheaper than buying online.
The chemical reaction between lye and fats is called saponification. This reaction is exothermic - it releases energy in the form of heat. (Some reactions are endothermic, or require energy to occur, and take it out of the environment in the form of heat. Paradoxically, even though heat is being "added" to the reaction, the reactants and products become cooler. This happens when you make ice cream, and add salt to the ice around the ice cream maker. If you checked the temperature of the ice, and then the ice and salt mixture, you would see that the temperature decreases. That's how you get temperatures cold enough to actually freeze the ice cream. Same thing when you put salt on your sidewalk to melt the ice. The temperature of the salt water would be colder than just the ice itself.) But I digress. Depending upon the oils you use, the temperatures you soap at, fragrance oils (FO) you use, and environmental temperatures, the saponification reaction can generate more or less heat. If the reaction gets hot enough, the soap goes through a gel phase. You can see this happening - it starts in the center of the mixture, because that's where it will get hottest first - the forming soap becomes darker and somewhat translucent in appearance. The gel phase will spread outward, sometimes stopping before it reaches the edge, sometimes completely gelling the entire batch. Large batches, and using log molds where the surface area ratio is low compared to the volume of the batch, tend to trap the heat being created by the reaction, encouraging gel to occur. Soap that goes through saponification without getting hot enough to go through a gel phase will be lighter in color and opaque in appearance compared to gelled soap.
Many new soapers ask which is better, gelled or non-gelled soap? The answer is neither, or rather, it depends upon your aesthetic preference. Gelled and non-gelled soap last the same amount of time, have the same lather, and the same properties. The only real difference is in appearance. Gelled soap is darker and has a tiny bit of translucence. Non-gelled soap is significantly lighter and opaque. I made a batch of soap, and put most of it in a log mold, and put the left overs in individual molds. The individual molds did not gel, while the log mold did gel. Here is a picture:
As you can see, the soap on the left is much lighter than the soap on the right, even though it came from the same batch.
The one nemesis with gelling is the dreaded "partial gel". This is where the center of the soap gels, but the edges do not. This results in a soap that is lighter and opaque on the outside, but darker on the inside. Imagine putting a half moon of the soap on the right in the middle of the soap on the left. Not attractive. Because you want to avoid partial gel, most soapers either encourage a full gel, or try to discourage it from happening at all. You can encourage gel in several ways: soap warm and keep the mold in a warm area, turn the oven on to 170 degrees F (76 - 77 degrees C) then turn it off and put your soap mold inside for several hours, or wrap the mold up in towels. I emphasized turn off the oven because if you don't, you could end up with the soap overheating, and a "volcano" eruption. I use a space blanket, which is cheap, easy, and doesn't use any gas or electricity like the oven. It is essentially a large sheet of silver mylar, and you can buy them in the camping sections of places like Target and Wal Mart, and even online at Amazon.com. I lay down a towel, then lay the space blanket on top (it is large, so I double it up). Put my mold on top, fill it, and wrap the blanket and towel over the mold. The soap will often rise in the middle, so I put some wood at the ends of my log mold to keep the space blanket off the top of the soap. I leave everything like that until the next day. Works like a charm. Here are pictures of my set up:
Avoiding gel can be much harder. If you live in a hot and humid place, it can be nearly impossible. Recipes high in some oils, like coconut, can be very difficult to keep from gelling. Suggestions: soap in small batches, use tray molds that spread the batter out, put it in the freezer or refrigerator, and soap cool. I just made a small, 1 lb test batch, put it in the freezer, and it gelled in the freezer! Preventing gel is trickier than ensuring a full gel. But if you absolutely love the creamy look of ungelled soap, you will eventually find what works for you.
Colloidal Oatmeal: I needed some colloidal oatmeal for a facial soap recipe I was testing, but didn't want to pay the high price of ordering it online. I did some Internet research, and my problem was solved.
The reason to use colloidal oatmeal is the particles are small enough that they evenly disperse throughout the soap mixture, so you get the benefit of the soothing quality of the oatmeal in the lather, and you don't get any rough pieces that might scratch your skin. To make it, just take old-fashioned oats (not instant, and I don't use quick-cook either), and put some in a food processor. Grind it up as small as possible. At this stage it is probably okay to use, but colloidal oatmeal is an extremely fine powder, and you probably won't get that with your food processor. Small coffee grinder to the rescue. Put some of the ground oatmeal in the coffee grinder (cleaned, of course), a few pulses, and voila! real colloidal oatmeal. WAY cheaper than buying online.
Saturday, April 23, 2011
Fatty Acid Composition of Oils
Fatty Acids, Part 2
Here is a list of oils commonly used in soap making, their major fatty acid make up and contribution to the finished properties of soap:
Almond Oil: Very high in oleic acid, so it contributes conditioning properties. Low to moderate amount of linoleic acid, so don't use large amounts to avoid rancidity and DOS.
Avocado Oil: High in oleic acid, moderate amount of palmitic acid, and low to moderate amount of linoleic acid. Good conditioning, contributes a bit to hardness. Don't use in large amounts to avoid DOS and rancidity.
Canola Oil: High in oleic acid with a moderate amount of linoleic. While conditioning, this oil would make soap prone to DOS and rancidity. Very little saturated fatty acids, so it will contribute to a soft bar of soap.
Castor Oil: Extremely high in ricinoleic acid, so it adds much conditioning and fluffy lather properties. Contains no saturated fatty acids, so too much will make a soft, sticky bar of soap.
Coconut Oil: Moderate amounts of saturated fatty acids, so it contributes to a hard bar of soap. High in lauric acid, which contributes to a rich, fluffy lather. Low to moderate amount of oleic acid. The amount of saturated fa;tty acids mean that generally speaking, the more coconut oil in the soap, the more drying it will be.
Cocoa Butter: Total amounts of fatty acids are high (palmitic and stearic). Would make a hard bar of soap with good conditioning due to the oleic acid. Similar to lard.
Crisco: Moderate amounts of palmitic acid, with some stearic acid, so it will contribute to a harder bar. High in oleic, so it is also a bit conditioning. Moderate amount of linoleic, so too much will make the soap prone to DOS (it happened to me!).
Grapeseed Oil: Very high in linoleic acid, so more than a token amount will make the bar very prone to rancidity and DOS. The amounts of other fatty acids don't make up for the large amount of linoleic, so I'd stick with bath and body products for this one.
Hemp Oil: Very similar to grapeseed. Very high in linoleic acid, so it will tend to go rancid and promote DOS. Even less of other fatty acids than grapeseed, so there is little to recommend it for soap.
Jojoba Oil: The only fatty acid in joboba oil is oleic, and there isn't that much to begin with, so unless you are using it as a superfatting oil (it is roughly made up of 50% unsaponifiables, so you could assume only half will react with the lye), there is little it offers to soap.
Lard: High in saturated fatty acids, so it will produce a hard bar, and very high in oleic acid, so it is conditioning.
Mango Butter: Very similar to lard in ratio of saturated to unsaturated fatty acids, so it would make a good veggie substitute. Hmmm....will have to try that!
Olive Oil: Very high in oleic acid, so it is very conditioning. Low to moderate amounts of palmitic (mostly) and stearic acid, so it will not create a very fluffy lather. Moderate amount of linoleic, which probably explains why some 100% castile soaps get DOS.
Palm Kernel Oil/Flakes: You want fluffy lather? This is the oil for you. Very high in lauric acid, with moderate amounts of myristic and palmitic acids. Moderate oleic acid as well. Be careful of using too much or the soap may be drying.
Palm Oil: Similar in properties to palm kernel oil, though the major saturated fatty acid is palmitic acid, not lauric acid. High amounts of oleic acid, so it should be more conditioning than PKO. Low to moderate amount of linoleic acid.
Rice Bran Oil: This is an interesting oil. Moderate to high amount of palmitic acid, so it would contribute to a harder bar, very high in oleic, so it is conditioning as well, but unfortunately also moderately high amount of linoleic acid, so unless used in tiny amounts, it should promote DOS and rancidity.
Safflower Oil: Extremely high in linoleic acid, with little else in its favor. Just avoid it, unless you want to use it in bath and body products.
Shea Butter: Very similar to mango butter, so therefore a good veggie substitute for lard. High in stearic acid (hard bar), and oleic acid (conditioning). A tad more linoleic acid than mango butter.
Soybean Oil: Another one very high in linoleic acid. Stick to bath and body products for this one.
There are many other oils out there, and Soapcalc has lots of other oils in its database. Feel free to use the information from my last two blog posts to determine the contributions some of the more esoteric oils would make to your soap. Use this information, and Soapcalc (or other lye calculator), to develop soap recipes that make a soap with YOUR desired properties. That's the art and science of making soap!
Feel free to copy and paste this information for your use, but please reference this page as your source.
Oil fatty acid compositions found at www.soapcalc.net
Here is a list of oils commonly used in soap making, their major fatty acid make up and contribution to the finished properties of soap:
Almond Oil: Very high in oleic acid, so it contributes conditioning properties. Low to moderate amount of linoleic acid, so don't use large amounts to avoid rancidity and DOS.
Avocado Oil: High in oleic acid, moderate amount of palmitic acid, and low to moderate amount of linoleic acid. Good conditioning, contributes a bit to hardness. Don't use in large amounts to avoid DOS and rancidity.
Canola Oil: High in oleic acid with a moderate amount of linoleic. While conditioning, this oil would make soap prone to DOS and rancidity. Very little saturated fatty acids, so it will contribute to a soft bar of soap.
Castor Oil: Extremely high in ricinoleic acid, so it adds much conditioning and fluffy lather properties. Contains no saturated fatty acids, so too much will make a soft, sticky bar of soap.
Coconut Oil: Moderate amounts of saturated fatty acids, so it contributes to a hard bar of soap. High in lauric acid, which contributes to a rich, fluffy lather. Low to moderate amount of oleic acid. The amount of saturated fa;tty acids mean that generally speaking, the more coconut oil in the soap, the more drying it will be.
Cocoa Butter: Total amounts of fatty acids are high (palmitic and stearic). Would make a hard bar of soap with good conditioning due to the oleic acid. Similar to lard.
Crisco: Moderate amounts of palmitic acid, with some stearic acid, so it will contribute to a harder bar. High in oleic, so it is also a bit conditioning. Moderate amount of linoleic, so too much will make the soap prone to DOS (it happened to me!).
Grapeseed Oil: Very high in linoleic acid, so more than a token amount will make the bar very prone to rancidity and DOS. The amounts of other fatty acids don't make up for the large amount of linoleic, so I'd stick with bath and body products for this one.
Hemp Oil: Very similar to grapeseed. Very high in linoleic acid, so it will tend to go rancid and promote DOS. Even less of other fatty acids than grapeseed, so there is little to recommend it for soap.
Jojoba Oil: The only fatty acid in joboba oil is oleic, and there isn't that much to begin with, so unless you are using it as a superfatting oil (it is roughly made up of 50% unsaponifiables, so you could assume only half will react with the lye), there is little it offers to soap.
Lard: High in saturated fatty acids, so it will produce a hard bar, and very high in oleic acid, so it is conditioning.
Mango Butter: Very similar to lard in ratio of saturated to unsaturated fatty acids, so it would make a good veggie substitute. Hmmm....will have to try that!
Olive Oil: Very high in oleic acid, so it is very conditioning. Low to moderate amounts of palmitic (mostly) and stearic acid, so it will not create a very fluffy lather. Moderate amount of linoleic, which probably explains why some 100% castile soaps get DOS.
Palm Kernel Oil/Flakes: You want fluffy lather? This is the oil for you. Very high in lauric acid, with moderate amounts of myristic and palmitic acids. Moderate oleic acid as well. Be careful of using too much or the soap may be drying.
Palm Oil: Similar in properties to palm kernel oil, though the major saturated fatty acid is palmitic acid, not lauric acid. High amounts of oleic acid, so it should be more conditioning than PKO. Low to moderate amount of linoleic acid.
Rice Bran Oil: This is an interesting oil. Moderate to high amount of palmitic acid, so it would contribute to a harder bar, very high in oleic, so it is conditioning as well, but unfortunately also moderately high amount of linoleic acid, so unless used in tiny amounts, it should promote DOS and rancidity.
Safflower Oil: Extremely high in linoleic acid, with little else in its favor. Just avoid it, unless you want to use it in bath and body products.
Shea Butter: Very similar to mango butter, so therefore a good veggie substitute for lard. High in stearic acid (hard bar), and oleic acid (conditioning). A tad more linoleic acid than mango butter.
Soybean Oil: Another one very high in linoleic acid. Stick to bath and body products for this one.
There are many other oils out there, and Soapcalc has lots of other oils in its database. Feel free to use the information from my last two blog posts to determine the contributions some of the more esoteric oils would make to your soap. Use this information, and Soapcalc (or other lye calculator), to develop soap recipes that make a soap with YOUR desired properties. That's the art and science of making soap!
Feel free to copy and paste this information for your use, but please reference this page as your source.
Oil fatty acid compositions found at www.soapcalc.net
Fatty Acids in Soap
There are so many different oils we can use to make soap, choosing which oils to use in a new recipe can get really confusing to the newbie soapmaker (and some of us who've been around the block a couple of times too!). Soapcalc (my favorite lye calculator, and topic of a future post), lists the fatty acid make up of all the oils in its database. However, unless you know what each fatty acid brings to the party, the information is only so helpful. Soapcalc does list the hardness, cleansing, conditioning, and lather properties of each oil. However, I find that as I develop new recipes to try out, I'm looking more and more often at the amounts of specific fatty acids in my oils, because I want to increase or decrease specific properties in my soap.
This post will describe the different fatty acids found in soap, and how they affect the properties of our finished soap. The next post will look at some of the more common oils we use in soap making, and the major fatty acid make up of each one. I'll start by explaining some basic chemistry of fatty acids. If high school or college chemistry gave you a headache, feel free to skip this next paragraph and go right to the list of fatty acids found in our soap making oils.
What IS a fatty acid? As the name implies, it is both a fat and an acid. The head of the molecule is a carboxylic acid, and the tail is a chain of carbon and hydrogen atoms of varying length. There may be some double bonds between the carbon atoms, making the fatty acid unsaturated, or there may be no double bonds, making it saturated (it has as many hydrogen atoms attached as is possible). The number and location of the double bonds contributes to the flexibility of the molecule, and the melting temperature of the oil. A non-scientific way of determining the relative saturation of oils is to see how solid the fat is at room temperature. The more solid the fat, the fewer double bonds it has. Saturated fatty acids (like stearic acid and palmitic acid), are quite hard at room temperature, and have high melting temperatures, while highly unsaturated oils (like olive oil), are liquid at room temperature, and stay liquid until they get fairly cool. Because of saturation/non-saturation, one can see that the more saturated the fatty acids in the oils and butters you use, the harder the finished bar of soap will be. Unsaturated oils will add more conditioning properties to soap.
Fatty Acids Found in Soap and Their Properties
A list of my sources of information:
Wikipedia entry on fatty acids
Wikipedia entry on carboxylic acids
Wikipedia entry on ricinoleic acid
Buzzle article on fatty acids
Fatty acid information
This post will describe the different fatty acids found in soap, and how they affect the properties of our finished soap. The next post will look at some of the more common oils we use in soap making, and the major fatty acid make up of each one. I'll start by explaining some basic chemistry of fatty acids. If high school or college chemistry gave you a headache, feel free to skip this next paragraph and go right to the list of fatty acids found in our soap making oils.
What IS a fatty acid? As the name implies, it is both a fat and an acid. The head of the molecule is a carboxylic acid, and the tail is a chain of carbon and hydrogen atoms of varying length. There may be some double bonds between the carbon atoms, making the fatty acid unsaturated, or there may be no double bonds, making it saturated (it has as many hydrogen atoms attached as is possible). The number and location of the double bonds contributes to the flexibility of the molecule, and the melting temperature of the oil. A non-scientific way of determining the relative saturation of oils is to see how solid the fat is at room temperature. The more solid the fat, the fewer double bonds it has. Saturated fatty acids (like stearic acid and palmitic acid), are quite hard at room temperature, and have high melting temperatures, while highly unsaturated oils (like olive oil), are liquid at room temperature, and stay liquid until they get fairly cool. Because of saturation/non-saturation, one can see that the more saturated the fatty acids in the oils and butters you use, the harder the finished bar of soap will be. Unsaturated oils will add more conditioning properties to soap.
Fatty Acids Found in Soap and Their Properties
- Lauric Acid: A saturated fatty acid that contributes to a hard bar, fluffy and stable lather, and high cleaning. Too much of this fatty acid can make a soap drying.
- Linoleic Acid: An unsaturated fatty acid adds conditioning to the soap. Oils high in this fatty acid tend to go rancid quickly, and more easily develop DOS (dreaded orange spots).
- Linolenic Acid: Not to be confused with linoleic acid. Adds conditioning properties and is very mild.
- Myristic Acid: A saturated fatty acid, so it adds to the hardness of the bar, fluffy lather, and cleansing ability. Soaps high in myristic can be very drying to the skin.
- Oleic Acid: An unsaturated fatty acid, so it adds conditioning properties. This fatty acid does not contribute much to the lather of a soap, but it does contribute to the "slippery" feeling of soap.
- Palmitic Acid: Another saturated fatty acid, so it will contribute to a hard bar and can by drying if too much is used. It contributes to a creamy, rather than fluffy lather.
- Ricinoleic Acid: Unsaturated, it adds conditioning properties, and is great for a fluffy, bubbly lather. Found almost exclusively, and in great quantities in castor oil.
- Stearic Acid: Saturated, so it contributes to a hard bar. It is very similar to palmitic acid, and is generally interchangeable with it. Contributes to a creamy lather.
A list of my sources of information:
Wikipedia entry on fatty acids
Wikipedia entry on carboxylic acids
Wikipedia entry on ricinoleic acid
Buzzle article on fatty acids
Fatty acid information
Friday, April 22, 2011
Introduction
As you can see in "About Me", I love both art and science. Soap-making a a wonderful marriage of both. There is definitely a science to making good soap, and crafting attractive soaps people want to use and display is an art. I wanted to create a blog that concentrates on both aspects of handcrafted soap-making. There is a lot of information out there on the Internet, and over time I'd like to consolidate a lot of that information in one place. I also would like to document my own explorations of the science and art of soap-making, and perhaps showcase the awesome work done by others. Finally, I'm slowly planning my own soap-making business, and want to share my experience to help others thinking of doing the same. Oh, the name of my blog? It will be my business name, and pretty much describes what I think is the standard for handcrafted soap.
Welcome, and I hope you enjoy the journey.
Welcome, and I hope you enjoy the journey.
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