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Some answers to questions that I had before I did it, and a review of lessons learned.
How hard is the bar/puck?
It's softer than a bar of bath soap such as Ivory. I can't really compare it to other shaving soaps since I'm new at this and haven't bought any. It's soft enough to deform when you squeeze it.
How much did it cost?
Here's the breakdown by ingredient. Wholesalesuppliesplus prices include shipping, so these are costs of the supplies delivered to my doorstep.
totals $4.78 in materials. I was more than a little surprised my potassium hydroxide was the most expensive ingredient after I analyzed the costs.
So the material cost of a 100g puck is about $0.68. That should be an eye opener. Adding fragrance will jack this up dramatically, more than a 100% increase for adding anything but the cheapest fragrance oils you can find.
I bought more feedstock than this, but these are the proportional costs based on the packages I bought.
I owned all the relevant equipment already,so I didn't have to invest anything in tools, but my guess on that would look like around 60-75 bucks for a crockpot, stick blender, digital scale and some miscellaneous stirring equipment. Already owning all of it was a significant driver in my decision to proceed.
How long will it last? (and what's the cost per shave?)
I looked over the cost per shave data mining thread. Hat tip to Jim. Even at higher loading rates like the 4g/shave some of those 3017ers report, I cooked up about enough (700g) to shave 175 times at a cost of under $0.03 a shave.
So I should expect to cook a batch this size twice a year if this is just for me. This is significant because the feedstock does not have an indefinite shelf life. I learned (after I bought the oils)that freezing them will retard oxidation a lot, pushing out the rancidity problem. Luckily, the oils in this recipe are among the very most stable.
There is a huge amount of technical information on soap making online, a lot of it in this forum. There's also a lot of what I'll call folklore. I tried hard to find info I could rely on, and to corroborate things I read on sites. Somewhere the last resort is to just do it and let your personal experience inform you. But thanks to everyone here who has documented their soaping.
I am in no way an expert on soap or chemistry, or even shaving. So here's what I'll present as my working understanding of why each ingredient is in this formula, and why the process steps are there as best I understand today.
Coconut oil
Coconut oil is high in Lauric acid, high in Myristic acid, and overall low in unsaturated fats. So it has good shelf life.
This oil is a good choice for shaving soaps in high proportions because of its lathering qualities, which derive from the lauric and myristic acid content being high. Being mostly saturated, coconut is solid at room temps, and contributes to a harder bar of soap.
Stearic acid
This is one single fatty acid (unlike a natural oil that contains multiple fats) refined from either vegetable or animal sources that contain multiple oils. You guys who like tallow soaps are actually likely to be fans of stearic acid in soap, since tallows are high in stearic. Like coconut oil, stearic is saturated, but the molecules are longer, giving it a higher melt point. Stearic acid is contributing to the hardness of the puck, and is making the lather hold up better (feel slicker). It's not contributing cleansing power. Being entirely saturated, shelf life is also great.
KOH (potassium hydroxide)
This is the caustic lye that when it reacts with the fatty acids above, turns them into soap. In this case potassium salts of the fatty acids. The other choice would have been sodium hydroxide. In general the potassium salts of fatty acids give better lather performance than the sodium salts, so most shaving soaps are at least partly saponified (turned into soap) by KOH. On the possible down side, KOH soap is softer than NaOH soap all else being equal. So some makers will saponify part of the oil with NaOH. You can split the batch in two and run two recipes through soapcalc.net if this is interesting to you. I thought the hardness of my batch with 100% KOH was perfectly adequate (in my far from expert opinion).
distilled water
I didn't make a real point of it, but using distilled water to dissolve your KOH avoids having the extra calcium carbonate in there to offer calcium. Since this costs so little I would not advise cutting this corner, but I can't say I appreciate how badly it may affect the outcome.
glycerin
I included this largely on the strength of wanting to follow JBLA's formula completely. When the lye and fatty acids react, you get glycerin as one of the byproducts. So the soap will contain a decent amount of glycerin without you adding any. My understanding of the goal in adding glycerin is to serve as a humectant, thereby offsetting some of the drying (grease cutting) tendencies of the lauric acid salts coming from the high fraction of coconut oil in this formula. It's helping your skin stay hydrated and elastic, and lasts after your shave is over. Pretty good for a cheap additive.
Process steps:
heating the oils
The oil has to be liquid to combine with the lye solution, and both our oils are solid at room temps. The melt point of stearic is up above 160°F depending on purity, while the coconut oil melts a little under body temps.
dissolving the lye
The dissolved lye breaks into K+ and OH- ions when it dissolves. The abundance of OH- (hydroxide) ions is what makes the lye water caustic, and is what you are measuring the proportion of when you take a pH measurement. The K+ ions attach to the fatty acids to make the salts like potassium stearate when we combine the oils and lye.
stick blender action
I didn't realize this until after I ran my batch, but just like making mayonnaise with a stick blender, you are creating an emulsion with the stick blender. Higher temps are helpful in getting it right, but the magic of stick blenders is that they are deluxe emulsion machines. This is why every soap hobbyist needs a stick blender. It's also why you can't arbitrarily increase the water to a point where the lye is super diluted and safe. There's a min and max amount of water you can successfully emulsify.
cooking time
Soap is done cooking at the point where there can't be further oil changed into soap. That point is reached when you cook out the lye solution, more or less. When we talk about superfatting, that means that you include more oil than the tables tell you can be saponified by the amount of lye you put in your formula. This is why careful measurements are important--you want to run out of lye in your reaction before you run out of fat to saponify, otherwise you get lye water on your face (ouch). Superfatting gives a certain margin of error too--your scale can be off. The smaller your batch, the worse of a problem this poses since the error in your scale will be constant.
glycerin addition
I talked about this above. Glycerin happens when you make soap, so we add more, but doing it at the end is sensible since our reaction complete or close to it. Read more about why glycerin is awesome here: http://swiftcraftymonkey.blogspot.com/2012/04/humectants-more-about-glycerin.html
Learn more about oil chemistry and why glycerin happens here:
http://swiftcraftymonkey.blogspot.com/2014/02/oil-chemistry-review-triglycerides-and.html
(cool pictures of oil molecules at the link above illustrating saturated versus unsaturated)
disclaimer
As noted above, I'm a new soaper and new shaver. I'm not even a chemist. Corrections to the above are welcome, and by all means don't take my word for anything, this is just my wrapup of what I learned from my first batch of shaving soap. I plan to do some bath bars and some after shave lotion soon.
How hard is the bar/puck?
It's softer than a bar of bath soap such as Ivory. I can't really compare it to other shaving soaps since I'm new at this and haven't bought any. It's soft enough to deform when you squeeze it.
How much did it cost?
Here's the breakdown by ingredient. Wholesalesuppliesplus prices include shipping, so these are costs of the supplies delivered to my doorstep.
| ingredient | cost in this recipe |
| coconut oil | $1.50 |
| stearic acid | $1.20 |
| distilled water | $0.05 |
| KOH | $1.85 |
| glycerin | $0.18 (estimated 1 oz--I didn't weigh it) |
totals $4.78 in materials. I was more than a little surprised my potassium hydroxide was the most expensive ingredient after I analyzed the costs.
So the material cost of a 100g puck is about $0.68. That should be an eye opener. Adding fragrance will jack this up dramatically, more than a 100% increase for adding anything but the cheapest fragrance oils you can find.
I bought more feedstock than this, but these are the proportional costs based on the packages I bought.
I owned all the relevant equipment already,so I didn't have to invest anything in tools, but my guess on that would look like around 60-75 bucks for a crockpot, stick blender, digital scale and some miscellaneous stirring equipment. Already owning all of it was a significant driver in my decision to proceed.
How long will it last? (and what's the cost per shave?)
I looked over the cost per shave data mining thread. Hat tip to Jim. Even at higher loading rates like the 4g/shave some of those 3017ers report, I cooked up about enough (700g) to shave 175 times at a cost of under $0.03 a shave.
So I should expect to cook a batch this size twice a year if this is just for me. This is significant because the feedstock does not have an indefinite shelf life. I learned (after I bought the oils)that freezing them will retard oxidation a lot, pushing out the rancidity problem. Luckily, the oils in this recipe are among the very most stable.
There is a huge amount of technical information on soap making online, a lot of it in this forum. There's also a lot of what I'll call folklore. I tried hard to find info I could rely on, and to corroborate things I read on sites. Somewhere the last resort is to just do it and let your personal experience inform you. But thanks to everyone here who has documented their soaping.
I am in no way an expert on soap or chemistry, or even shaving. So here's what I'll present as my working understanding of why each ingredient is in this formula, and why the process steps are there as best I understand today.
Coconut oil
Coconut oil is high in Lauric acid, high in Myristic acid, and overall low in unsaturated fats. So it has good shelf life.
This oil is a good choice for shaving soaps in high proportions because of its lathering qualities, which derive from the lauric and myristic acid content being high. Being mostly saturated, coconut is solid at room temps, and contributes to a harder bar of soap.
Stearic acid
This is one single fatty acid (unlike a natural oil that contains multiple fats) refined from either vegetable or animal sources that contain multiple oils. You guys who like tallow soaps are actually likely to be fans of stearic acid in soap, since tallows are high in stearic. Like coconut oil, stearic is saturated, but the molecules are longer, giving it a higher melt point. Stearic acid is contributing to the hardness of the puck, and is making the lather hold up better (feel slicker). It's not contributing cleansing power. Being entirely saturated, shelf life is also great.
KOH (potassium hydroxide)
This is the caustic lye that when it reacts with the fatty acids above, turns them into soap. In this case potassium salts of the fatty acids. The other choice would have been sodium hydroxide. In general the potassium salts of fatty acids give better lather performance than the sodium salts, so most shaving soaps are at least partly saponified (turned into soap) by KOH. On the possible down side, KOH soap is softer than NaOH soap all else being equal. So some makers will saponify part of the oil with NaOH. You can split the batch in two and run two recipes through soapcalc.net if this is interesting to you. I thought the hardness of my batch with 100% KOH was perfectly adequate (in my far from expert opinion).
distilled water
I didn't make a real point of it, but using distilled water to dissolve your KOH avoids having the extra calcium carbonate in there to offer calcium. Since this costs so little I would not advise cutting this corner, but I can't say I appreciate how badly it may affect the outcome.
glycerin
I included this largely on the strength of wanting to follow JBLA's formula completely. When the lye and fatty acids react, you get glycerin as one of the byproducts. So the soap will contain a decent amount of glycerin without you adding any. My understanding of the goal in adding glycerin is to serve as a humectant, thereby offsetting some of the drying (grease cutting) tendencies of the lauric acid salts coming from the high fraction of coconut oil in this formula. It's helping your skin stay hydrated and elastic, and lasts after your shave is over. Pretty good for a cheap additive.
Process steps:
heating the oils
The oil has to be liquid to combine with the lye solution, and both our oils are solid at room temps. The melt point of stearic is up above 160°F depending on purity, while the coconut oil melts a little under body temps.
dissolving the lye
The dissolved lye breaks into K+ and OH- ions when it dissolves. The abundance of OH- (hydroxide) ions is what makes the lye water caustic, and is what you are measuring the proportion of when you take a pH measurement. The K+ ions attach to the fatty acids to make the salts like potassium stearate when we combine the oils and lye.
stick blender action
I didn't realize this until after I ran my batch, but just like making mayonnaise with a stick blender, you are creating an emulsion with the stick blender. Higher temps are helpful in getting it right, but the magic of stick blenders is that they are deluxe emulsion machines. This is why every soap hobbyist needs a stick blender. It's also why you can't arbitrarily increase the water to a point where the lye is super diluted and safe. There's a min and max amount of water you can successfully emulsify.
cooking time
Soap is done cooking at the point where there can't be further oil changed into soap. That point is reached when you cook out the lye solution, more or less. When we talk about superfatting, that means that you include more oil than the tables tell you can be saponified by the amount of lye you put in your formula. This is why careful measurements are important--you want to run out of lye in your reaction before you run out of fat to saponify, otherwise you get lye water on your face (ouch). Superfatting gives a certain margin of error too--your scale can be off. The smaller your batch, the worse of a problem this poses since the error in your scale will be constant.
glycerin addition
I talked about this above. Glycerin happens when you make soap, so we add more, but doing it at the end is sensible since our reaction complete or close to it. Read more about why glycerin is awesome here: http://swiftcraftymonkey.blogspot.com/2012/04/humectants-more-about-glycerin.html
Learn more about oil chemistry and why glycerin happens here:
http://swiftcraftymonkey.blogspot.com/2014/02/oil-chemistry-review-triglycerides-and.html
(cool pictures of oil molecules at the link above illustrating saturated versus unsaturated)
disclaimer
As noted above, I'm a new soaper and new shaver. I'm not even a chemist. Corrections to the above are welcome, and by all means don't take my word for anything, this is just my wrapup of what I learned from my first batch of shaving soap. I plan to do some bath bars and some after shave lotion soon.
