Soap Dish Idea

Gosh, it's been a while since I've posted.  I guess that's what happens at the end of the school year with report cards to write and all the end of year stuff to get through.  School is officially over, and I've got several ideas for posts to write, so I think I'll "catch-up" soon. And while I have several science of soapmaking topics to write about, I've also got several artsy-related topics as well. And so I'll start with one of those...

A couple of weeks ago three of us from the Soapmaking Forum, who live in Pennsylvania, got together for a Saturday of soap-related conversation and activities.  Though we didn't make soap, we did make some soap dishes. I got the idea from a picture posted on the Soapmaking Forum.  I bought a length of wood moulding from Lowe's that had deep grooves in it. We cut the moulding into 5 inch lengths (about 13 cm), and sanded the edges.  Then we sealed the wood with a non-toxic sealant made from beeswax and mineral oil (recipe below). Rubbed the sealer into the wood really well, let it sit for a bit then wiped off the excess. After some time to dry, they were ready to use. Here is a picture of one of my soap dishes:

Here is the wood sealer recipe:

1 cup mineral oil  (236 ml)
1.6 oz. beeswax.   (45 g)

    Heat the mineral oil on low heat for about 5 minutes, then add the beeswax.  Stir when melted. Pour into a jar and let solidify.  Rub into the wood. 

I got the recipe for the wood sealer from:
Non-toxic wood sealer from E-How.com

Soap Chemistry 103

Before we get to the actual saponification reaction, there is one more chemical concept we need to explore. This is the ester. Remember from the last chemistry post that the reaction of an acid and a base produces a salt and water. Alcohols will also react with acids, but instead of producing a salt and water, they create an ester and water. This is a kind of condensation reaction, because of the formation of a water molecule from the original reactants. Esters are essentially insoluble in water, a property that we will come back to later. This is because the carbon/hydrogen tail is long enough that it counteracts the solubility of the head formed from the alcohol. If you mix an ester and a base, you get back the original alcohol and a salt in a type of hydrolysis reaction. If you look at the different parts of that word, you can see the hydro, meaning water, and lysis, which is to break apart. A hydrolysis reaction reinserts the water molecule lost in the condensation reaction to break apart the molecule. If the base is sodium hydroxide (lye) you will get a sodium salt. An important alcohol in soapmaking is glycerol, better known to soapmakers as glycerin. We'll talk much more about glycerin below.

Now that we've covered the chemistry of water and oils, acids and bases, fatty acids, and a little bit about esters, we're ready to tackle the reaction that creates soap: saponification. Though we talk about the fatty acids found in oils, in reality it isn't the fatty acids that are in coconut and olive oils, for example, but their esters. The fatty acid ester structure found in oils consists of three fatty acids attached to one glycerol molecule, formed by a condensation reaction. Chemists call these molecules triacylglycerides, the acyl part (or group) being the part that is formed from the fatty acids. The three fatty acids don't have to be all of the same type, either. Olive oil contains stearic, ricinoleic, linoleic, and linolenic fatty acids, and the triacylglyceride molecules can contain any combination of those fatty acids as the acyl parts of the molecule. The proportion, however, of all the acyl groups matches the proportion you find on Soapcalc for the fatty acids. You've heard of triacylglycerides as triglycerides, the very fatty molecules that you don't want a lot of in your blood. Trigylcerides, being esters, have non-polar covalent bonds and are not soluble, which explains why oils do not mix with water. I mentioned above that if you mix an ester and a base, a hydrolysis reaction occurs, resulting in a salt and the original alcohol. Therefore, when you add lye (sodium hydroxide), to your oils when making soap, the reaction forms glycerol and sodium salts of the fatty acids in the esters. That's the source of the glycerin in handcrafted soap. Fatty acid salts are soaps. Remember, the fatty acid has a water soluble head, and an insoluble tail. They are also alkalis, which have a basic (greater than 7) pH. Knowing how the saponification works also gives us the information on how to calculate the amount of glycerin formed from the reaction. For every three fatty acid molecules produced, one glycerol molecule will be produced. So the ratio of glycerin to fatty acid molecules is 1:3. You can actually calculate the weight of glycerin in a batch of soap. I refer you to Kevin Dunn's Scientific Soapmaking, pages 218 and 219 if you want to calculate the weight (or more correctly, mass) of glycerin in your finished soap.

We aren't finished with soap chemistry. To come later: how and why some FO's accelerate trace, why FO's often change in the finished soap, soaps versus detergents, soap scum, and those dreaded orange spots (DOS).

My Vegan "Lard" Bar

Tried a new soap this morning in the shower, and I just had to write about it, so I'm taking a mini-break from the chemistry "lectures."

I bought some lard this past winter to make suet cakes for the bird feeders at school (I have a bird club that collects and sends data to the Cornell Institute of Ornithology through their Project FeederWatch Program).  Found out the hard way that was a mistake.  Lard melts WAY too easily. I ended up with an extra one pound container of lard for which I had no use.  I prefer to make soap from plant oils, but I didn't want the lard to go to waste, so I made a four bar batch of lard soap, concocting a recipe on Soapcalc.net that had the properties I wanted.  I also tested out a new FO - Nature's Garden Exotic Amazon Teakwood, as I wanted to try out a more manly scent for my husband.

Some people really love lard soap, and now I can see why. It makes a hard bar with thick, creamy lather. Not as bubbly as my usual recipe, but I really liked it for a change.  My husband liked the soap and the scent.  I loved the scent too; manly enough for a "men's line," yet it didn't make me feel like I bathed with Old Spice or something like that.  Now I had a problem.  I liked the soap, but still preferred to use plant oils and butters.  Lard is also a bit smelly to make soap out of, much like milk soaps can stink until they cure. When researching fatty acids for one of my earliest posts, I discovered that mango butter (as well as shea and cocoa butters) has a fatty acid profile similar to lard. The plant butters, however, have much higher amounts of ricinoleic acid, which should increase the lather compared to lard.  So I developed a mango butter soap recipe similar to my lard recipe (I had some mango butter on hand).  I tried a different FO (Nature's Garden Pineapple Paprika) that I thought would work well with the mango theme.  Finally tried the soap this morning, after a four or five week cure.  Impression?  Love it!  It has a lot of lovely, creamy lather much like the lard soap, maybe even better, and the FO smelled terrific. It feels just as hard as the lard soap, which is what I expected from my Soapcalc numbers.   The only downside is that mango butter isn't cheap, especially compared to lard.  But I think it makes a great vegan "lard" bar substitute.

I'm going to keep one of the mango butter bars around for about a year, as well as a lard bar,  to see what happens.  Mango, shea, and cocoa butters all have high amounts of linoleic acid, as does lard.  This fatty acid can make soap that is prone to getting DOS.  I want to see how long those bars will last for me.

Unfotunately, I'm not posting a picture of the soap.  The FO made the lye/oil mixture seize on me, so the bars are not especially pretty.  But that's another post.

Soap Chemistry 102

Fatty acids are the most important chemicals found in soap. They are what makes soap soapy. I talked about fats in the last post, but haven't talked about acids. Because fatty acids are both fats and acidic, I'm going to start by taking a little detour to explain acids and bases (lye is a base, and you already know you can't make soap without it!).

Acids are chemicals that can donate a hydronium ion to another substance in a reaction. We already met the hydronium ion in the last post – it is a hydrogen atom that had it's electron “stolen”. Because a hydrogen atom has only one proton and one electron, a hydronium ion is simply a lone, positively charged proton. A base is a chemical that can accept a proton in a chemical reaction. Sodium hydroxide has the chemical formula NaOH. It has one sodium atom, one oxygen, and one hydrogen atom. The oxygen and hydrogen are bonded together with a covalent bond; it is called a hydroxide group when part of a larger molecule. The hydroxide group has an ionic bond to the sodium. When dissolved in water, the sodium dissociates from the hydroxide. The hydroxide group steals an electron from the sodium, so the dissociation forms sodium and hydroxide ions. It is the hydroxide group that can accept a proton, since it is negatively charged due to the "stolen" electron. Sodium hydroxide is a strong base, which means it completely ionizes when dissolved in water. Potassium hydroxide (also called lye) works the same way. When acids and bases react, they form a salt and water. It may seem hard to believe, but if you mix just the right amounts of sodium hydroxide and hydrochloric acid (which is a strong acid), you will get plain old salt water – table salt (NaCl) and water. It is the reaction of an acid and a base that is the basis of the saponification reaction – but more about that later. The pH scale is a measure of the concentration of hydronium ions in a solution. The lower the number, the more concentrated it is with hydronium ions, and the more acidic. The pH scale ranges from 1 to 14, with 7 being neutral. Bases have a pH greater than 7. The higher the number, the more basic the chemical is. Soap, of course, is a base. We expect our soap to have a pH of 8 to 10 if it is safe and not lye-heavy.

Fatty acids are molecules that have a carboxylic acid group on one end of the molecule. This means they have a positively charged hydrogen ion bonded to a negatively charged oxygen ion. The oxygen is also bonded to a carbon atom, and the carbon atom also shares a double bond with another oxygen atom. A double bond is when two atoms share two electrons, rather than just one. This is the acidic end of the molecule, as it can donate a proton to another atom or molecule. If you remember from the last post, carbon is looking to share four electrons, and so far we have accounted for only three: the single bond to the oxygen with the hydrogen, and the double bond to the other oxygen. This is where the fatty tail of the molecule is found. Again, a fat is simply a chain of carbon atoms bonded to each other with attached hydrogen atoms to fill up the need for four shared electrons. Each carbon is generally bound to two other carbons, and shares electrons with two hydrogen atoms. This is called a saturated fat, since no more hydrogen atoms can bond to the molecule. In some fatty acids, one, two, or three of the carbons shares a double bond with a carbon next to it, so each carbon involved in the double bond is bonded to only one other hydrogen. This is called an unsaturated fat, because it is possible to break the double bond and add two hydrogen atoms to the molecule for each double bond it has. These double bonds will become important in a later post. And yes, when you are reading a nutrition label this is exactly what it is talking about when it lists the amount of saturated and unsaturated fats. I'll be talking more about saturated and unsaturated fatty acids later as well.

So a fatty acid has a carbon-hydrogen tail attached to the carbon of the carboxylic acid group. Remember, carbon and hydrogen form non-polar covalent bonds, while hydrogen and oxygen form a polar covalent bond. The two ends of the molecule exhibit very different chemistries. The difference between fatty acids is due to the number of carbons in the fatty tail, as well as the presence of any double bonds between the carbons. The smallest fatty acid is acetic acid – its fatty acid tail contains only one carbon. Because the tail is so short, it is relatively soluble in water, and acts much more like an acid than a fat. We all know acetic acid as vinegar. The longer the carbon chain, the less soluble the fatty acid is in water.

The saturated fatty acids we are familiar with in soap making are lauric acid, myristic acid, plamitic acid, and stearic acid. Lauric acid has the shortest carbon chain, so it is the most soluble in water. Soaps with a lot of lauric acid (coconut and palm kernel oils) will produce a lot of lather quickly because of this. Stearic acid is the longest chain, so is least soluble. Soaps high in stearic acid take more time to lather (palm, lard, and tallow) and the lather is not as fluffy.

The unsaturated fatty acids common to soap making are oleic acid, ricinoleic acid, linoleic acid, and linolenic acid. All of these contain 18 carbons in the chain, so the difference between them is how many double bonds they have. Both oleic and ricinoleic acid have one double bond; ricinoleic acid has a hydroxide group attached to a carbon near the double bond. The length of the chains means that these fatty acids are less soluble than all of the saturated fatty acids except stearic acid, which also has 18 carbons in the chain. Therefore they will lather slowly with the exception of ricinoleic. The polar hydroxide group on the chain increases it's solubility significantly, giving soaps that contain it lots of quick, fluffy lather.

Now we are ready to make soap. Next up is the chemistry of the saponification reaction.

Soap Chemistry 101

I recently bought Kevin Dunn's book, Scientific Soapmaking. It was written both as a reference for soapmakers who are interested in learning about the chemistry behind their craft, and as a potential textbook for chemistry students. Having two such disparate audiences does cause some problems, however. Unless you have a basic chemistry background (recent high school chemistry class or a college introductory class), it has a lot of technical information that could make it a tough read. There are also quite a few “experiments” and demonstrations that most people would find tedious and unecessary. That said, I thought it was a fabulous book. Luckily I have a pretty strong background in chemistry (albeit many years ago), so I found it to be a fascinating read. There were quite a few “aha!” moments where observations I've made while soaping, or situations I've read about, suddenly were explained and made sense. The information I gleaned from this book is valuable to any soapmaker, so in the next few posts I plan on summarizing what I've learned, hopefully presenting it in a manner that is more accessible to non-chemists. Note to those who are comfortable with chemistry concepts: in my explanations below and future posts I will simplify some descriptions in order to avoid unnecessary confusion. Please keep that in mind! I'm not going to go into the particle/wave duality of electrons for example, or detail what an electron cloud is, as these concepts are not germane to this discussion. They are just going to be particles.

Before we can begin to talk about the chemistry of making soap, we need to understand the chemistry of water and oils. We all know water and oil don't mix, but why? Let's start with an examination of the chemistry of water. When we compare that to the chemistry of oils, the differences will explain why oil and water don't mix.

Water is made up of two hydrogen atoms and one oxygen atom. Each atom of a specific element (the basic building blocks of all chemicals; examples are hydrogen, carbon, oxygen, sodium, potassium, and nitrogen) has an equal number of particles called protons and electrons. Protons have a positive charge and are found in the nucleus of the atom, while electrons have a negative charge and are found in different levels (also called orbits) of the periphery of the atom. Because there are equal numbers of protons and electrons in an atom, the atom as a whole is neutral. Even though the atoms are neutral, most elements have atoms with enough physical space in their outermost level to accommodate more electrons, and this is the basis for how all elements combine with each other to form molecules. Every hydrogen atom has space for one more electron, and oxygen has enough space for two electrons. What happens is that two hydrogen atoms share their single electron with oxygen, which shares two of it's electrons with the hydrogen atoms. So the hydrogen atoms now appear to have all the electrons they can hold, and the same is true for the oxygen. When atoms bond together and share electrons, it is called a covalent bond. Oxygen, however, is a bit greedy. It is a much bigger atom than hydrogen, and doesn't share the electrons equally. So the electrons spend more of their time closer to the oxygen atom, giving it a slightly negative charge, while the hydrogen atoms end up with a slightly positive charge because their electrons are being hogged by the oxygen. When atoms share electrons unequally, this is called a polar covalent bond, since the molecule has a slight positive charge on one side, and a slight negative charge on the other. This polarity has a huge effect on the chemistry of the resulting molecule. In the case of water, the slightly positive hydrogens are attracted to the slightly negative oxygens of other water molecules, and will form weak bonds with them. This is called a hydrogen bond. It is not as strong as a bond that holds the atoms in molecules together, but is strong enough so that water molecules are very attracted to each other. Hydrogen bonds are responsible for the fact that water seems to form a “skin”, which is why you can fill a glass so that the water actually bulges up above the rim. Hydrogen bonds are important in more than just water too. Hydrogen bonding is responsible for much of the physical shape of a protein molecule, for instance. It takes energy to break hydrogen bonds. This is why sweating cools you down. The hydrogen bonds must be broken before the liquid water can evaporate off your skin, so energy in the form of heat is drawn from your body to power the evaporation.

Fats and oils, on the other hand, are made up almost entirely of chains of carbon and hydrogen atoms. Carbon and hydrogen atoms also form covalent bonds, but they are non-polar covalent bonds. The electrons are shared equally between the carbon and hydrogen atoms, so the entire molecule is neutral – there is no area of positive or negative charge. Each carbon atom is looking for four extra electrons, so it will share an electron with up to four other hydrogen atoms.

There is a third type of molecular bond that we will eventually need to know about, and that is the ionic bond. In ionic bonds, one of the atoms has the ability to completely steal an electron from the other atom. When you dissolve a substance with an ionic bond, the atoms will separate, with one atom (or group of atoms) stealing an electron from the other. Table salt, for example, is made of sodium and chlorine atoms, and has the chemical formula NaCl. When you dissolve salt in water, the sodium and chlorine dissociate to form sodium ions and chlorine ions. Ions are atoms that are missing or have an extra electron attached to them. Hence the name, “ionic” bond. These ions are very reactive.

You may have heard the saying “like dissolves like.” Water, having polar covalent bonds, can dissolve substances with polar covalent or ionic bonds. Oils, on the other hand, can't dissolve in water, because it has non-polar covalent bonds. The oily dirt on our skin can't be easily washed off with just water, because it can't dissolve in water.

This is where soap comes in. The chemistry of a soap molecule is such that one end of it has a polar covalent bond, while the tail is make up of carbon and hydrogen atoms that have non-polar bonds. The oily dirt on our skin dissolves in the non-polar part of the molecule, while the polar end dissolves in water, blending or emulsifying the oil/water mixture, and allowing the dirt to be washed away.

That's enough for this post. This information gives us the background to understand the structure of fatty acids, our next “lesson” in soap chemistry.

Fragrance Oil Tests

I've done several rounds of fragrance oil (FO) tests in the past few weeks. I bought at least 30 samples of different FOs from several online sites, all to see which ones might be candidates for selling in the future. I made a one pound batch of my simplest recipe, and poured about one ounce per paper cup at light trace (hence more than one test batch). I used plastic droppers to put in approximately 1.5 ml of FO in each cup, and used popsicle sticks to stir in the FO.  That roughly equates to 0.7 ounces per pound of oil. Since I knew the FO's might discolor the soap, I made sure one cup had no FO.  Wow! It is amazing how much the FO can change the color of soap. One of the cups was as white as the cup without any FO, while the rest ranged from slightly creamier to dark brown. I knew that vanilla in the FO makes the soap turn various shades of tan to brown, depending upon the concentration of the vanilla, and I found that it doesn't take all that much to turn the soap brown.  Ironically, the "Wedding Cake" scent was the darkest of all. I wanted to make soap cupcakes for my students with that one, but I guess they'll just have to look like chocolate cupcakes!  I didn't take a picture of all 30 scents, but I did take a picture of the finalists, showing the range of discoloration.

The soap on the far left by itself has no FO. The darkest is the "wedding cake" FO.

This little experiment taught me that unless I don't care about the color of my soap, it is very important to see how the FO will change it. It is also important to know that the color change can occur over several days - to almost a week, so wait at least that long to determine the final effect.

As for scent, it became apparent that it too, changes over time, again over several days.  What it smells like out of the bottle is often not a good indication of what it will smell like once soaped. And several scents changed significantly for the better after a few days.

Lesson learned?  Test! Test! Test!

Note: My tests were done with CP soap.  Melt and pour is an entirely different animal. I'll get to that sometime in the future.

Salt Bars!

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!

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.

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.

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

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

• 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. 

Feel free to copy and paste this information for your future use. However, please reference this page as your source. 


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

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.