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DeeAnna

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Geek Tip -- How much glycerin is in soap?

I posted a "Geek Tip" in another thread today, and one of the participants suggested starting a thread. I don't think I personally can come up with a tip every day, but I know I'm not the only one with useful but rather geeky ideas, so please feel free to chime in with tips of your own.

To get things started, here's my Geek Tip for today:

A quick way to accurately calculate the amount of glycerin created by saponification --

About 0.77 gram of glycerin is produced for every 1 gram of NaOH used to make soap. The soap must have a zero to a positive superfat for this to be accurate.

Glycerin weight, grams = (NaOH weight, grams) X 0.77
 
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jules92207

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This is an awesome idea. If I can contribute you know I will.
 

DeeAnna

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Geek Tip -- The difference between high-, mid-, and low-oleic oils

Safflower and sunflower oils are sold in high oleic, mid oleic, and linoleic (regular low oleic) versions depending on the amount of oleic acid in the oil. The differences in the fatty acid content comes from natural variations in sunflower and safflower plants. These differences have been enhanced by conventional plant breeding methods.

Regular low oleic (aka linoleic) oils contain mostly polyunsaturated fatty acids -- specifically linoleic and linolenic acids. These fatty acids become rancid fairly quickly in storage and break down quickly when heated. Mid oleic and high oleic oils contain at least 50% oleic acid, which is a more stable monounsaturated fatty acid. These higher-oleic oils will not break down as fast when used in the kitchen for frying and sauteeing. They work better in soap because they are not as prone to becoming rancid (also called DOS, dreaded orange spots). High oleic safflower or sunflower is a good substitute for olive oil.

So how to tell the difference? First, check the label for phrases such as "good for frying or sauteeing" or "high temperature" or even "high oleic," all of which will tell you the oil is a high oleic version.

If you don't see any helpful information like that, then use the nutrition information to calculate an answer --

% oleic (monounsaturated) = (grams monounsaturated fat per serving) / (grams total fat per serving) X 100%

If the monounsaturated fat is above 75%, it is a high-oleic oil.
If it is between 50% and 70%, it would be a mid-oleic oil.
If it is about 20%, it would be regular (linoleic) version.
 

afbrat

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Thanks for that tidbit! I wondered about that. Have not ventured past lard, CO and OO yet, but I probably will at some point :)
 

BrewerGeorge

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Not sure if this qualifies as a "geek" tip, but it's certainly a tip:

If you need to freeze milk, coconut milk, beer, or whatever for soaping, forget the ice cube trays. Instead, pour the liquid into a gallon ziplock bag and lay it flat in the freezer. (Obviously, make triple-sure that the top is closed! And if you're worried about leaks, use a paperclip to fold up the corners - they mostly only leak from the corners.) The hugely improved surface area to volume allows it to freeze FAST. Like, a pint will freeze to hard slush in 20 minutes fast. Not only that, but once it freezes to the hard slush stage, you can squeeze the bag to break up the ice crystals so it can be scooped out and measured like a paste instead of 1/2 oz blocks of hard ice.

If you don't want to waste the bag (I still cringe every time I throw one away because I'm cheap frugal) you can achieve similar results by pouring the liquid into a thin layer on a plate or sheet pan and using a fork to scrape up the ice crystals.
 

gigisiguenza

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I like the Ziploc baggie idea and am gonna try it. TY.
 

gigisiguenza

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If you want it to freeze even faster, wrap a damp paper towel around that bag.
I do that to get a soda bottle cold quickly, hadn't thought to do it with frozen lyewater alternatives. TY
 

kumudini

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Not sure if this qualifies as a "geek" tip, but it's certainly a tip:

If you need to freeze milk, coconut milk, beer, or whatever for soaping, forget the ice cube trays. Instead, pour the liquid into a gallon ziplock bag and lay it flat in the freezer. (Obviously, make triple-sure that the top is closed! And if you're worried about leaks, use a paperclip to fold up the corners - they mostly only leak from the corners.) The hugely improved surface area to volume allows it to freeze FAST. Like, a pint will freeze to hard slush in 20 minutes fast. Not only that, but once it freezes to the hard slush stage, you can squeeze the bag to break up the ice crystals so it can be scooped out and measured like a paste instead of 1/2 oz blocks of hard ice.

If you don't want to waste the bag (I still cringe every time I throw one away because I'm cheap frugal) you can achieve similar results by pouring the liquid into a thin layer on a plate or sheet pan and using a fork to scrape up the ice crystals.
That's a great tip if you want to freeze something and use. But for people like me who don't want to mix lye with anything other than water, just use 50% lye solution and the rest of the liquid amount for your additive, added directly into oils.
 

DeeAnna

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Geek Tip -- First aid for Lye Burns

For the sake of those who may have heard to use vinegar to treat a lye spill on your body -- that advice is absolutely wrong!

Never, never, NEVER use vinegar on a lye splash anywhere on your body. Rinse with plenty of plain cool running water.

***

The correct first aid if you get lye (NaOH or KOH) or raw soap batter on the body is this -- Rinse with plenty of plain cool running water. If you don't have access to clean water, rinse in the nearest mud puddle -- but you have to rinse!

You have SECONDS to react, so MOVE FAST. The quicker and more thoroughly you get the lye rinsed off, the better. Rinse for at least 10 minutes. Remove contacts and contaminated clothing as soon as possible. If the lye is under the fingernails or in other crevices, gently scrub and clean those areas carefully to remove all traces of lye.

If the burn is in or near the eyes, nose, or mouth or is a deep or large burn, see a doctor or emergency room for treatment immediately after you have rinsed well with water.

Treat small, mild lye burns just as you would any second degree burn. Keep the wound covered and moist with a water-based product. Do not use oily salves, butter, or other fatty stuff on any burn.

***

The geek explanation of why using vinegar is a Very Bad Idea --

Vinegar, an acid, does indeed neutralize lye, an alkali, but there are serious downsides to doing this kind of chemistry directly on the body.

First, the your skin is already being damaged by the lye. Alkali burn ... ouch!

Adding vinegar to the lye will trigger that neutralization reaction, which releases plenty of heat. If you know how hot your lye solution gets right after you mix the lye with water, you know exactly what I'm talking about. Thermal burn ... ouch!

On top of that, the vinegar itself, being acidic, will irritate the body tissues already injured by the lye and the heat. Acid burn ... more ouch!

All this damage results in intense pain and possibly a deeper, slower healing wound. Yikes!

To make matters worse, lye is a strong alkali and vinegar is a weak acid, so you need to use lots of vinegar in proportion to the amount of lye on the body. If you don't use enough vinegar and don't rinse long enough, the lye will remain active and continue to do its damage.

So if you want an alkali burn + a heat burn + an acid burn + major pain + a slow healing wound ... then by all means, use vinegar.

I will stick to plenty of cool running water, thank you very much!

***

If it makes you feel better to spray vinegar around your work area and to rinse your utensils with vinegar, then do so. You aren't going to harm anything by using vinegar on non-living things. That said, just a good rinse with water is really all that's needed for them as well.

For cleaning soapy or oily bowls and utensils that may have active lye on them, I wipe the items with old towels to remove excess soap and oil residues and then rinse the items well with water. I use a synthetic detergent cleaner like Dawn and hot water to do a final wash.

The soapy/oily/alkali-covered towels go into a plastic bucket far out of reach of curious human hands and critter paws. Once the residues have had a day or so to saponify, the towels gets washed with dirty chore clothes.

Everyone has a favorite way of cleaning up their work area and equipment after soaping; this is just my method.
 
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afbrat

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Thank you! I have read so many different conflicting pieces of advice about vinegar and lye. I am not a science minded person, so it is very hard to cull out bad info. That explanation makes sense! And thank you for the towels in the bucket idea! I have a bucket I can use. Will make my clean up easier!
 

DeeAnna

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Geek tip -- Why should you NOT use "full water" in your recipes?

Many soap recipe calculators have a default "full water" setting of "38% water as % of oils", and that's what a lot of cold process (CP) soapers use. Many do so because they don't realize there are benefits from using less water. Or perhaps a soaping teacher or adviser has mysteriously cautioned against the perils of using "discounted water" recipes.

I would like to encourage you to try a bit less water when you make CP soap next time, and see what you think.

Why would you want to use less water? Here are some reasons:

... harder soap at the time of unmolding so you can unmold and cut sooner
... batter is faster to come to trace, which is nice for simple recipes or doing higher volume production
... faster rate of saponification which is good for recipes high in unsaturated fats (castile being the prime example)
... less chance of emulsion failure (separation) in the mold
... less likely for the soap to go into gel on its own (less need for fans, fridge, or freezer!)
... less likely to show streaking or mottling (aka glycerin rivers)

That said, a little extra water can sometimes be helpful. Here are some reasons for using more water --

... slower rate of saponification which is good for recipes high in lauric and myristic acids (100% coconut oil being the prime example)
... taming naughty floral and spice fragrances that want to accelerate trace
... batter is slower to come to trace for fancy decorative swirls and such
... more likely for the soap to go into full gel on its own

I will explain how to use less water in the next Geek Tip -- it's pretty simple!

Geek tip -- How to calculate a recipe with less water

As I said before, many soap recipe calculators are set to a default of 38% water as % of oils.

To use less water, I encourage you to change from "water as % of oils" to "lye concentration" and things will be much much easier and more consistent. Pull up your favorite soap calculator and figure out how to do that. For example, in SoapCalc and in Soapee, these settings are contained in Section 3. Click in the round circle to the left of "lye concentration" to change from "water as % of oils" to concentration. Simple!

Next, think about the soap you are planning. When you used the default of 38% water as % of oils, you were creating recipes that used an average lye concentration of about 28%. To make a recipe that uses less water, you will want to make the lye more concentrated -- in other words, you will want to type a larger number for the concentration.

I suggest you try a 30% lye concentration for your first experience and see what you think. I know -- a change of just 2% doesn't seem like much, but trust me -- a small change in lye concentration can make a definite difference in how your soap behaves. Don't go overboard!

As you get some experience with using less water, you'll soon figure out what basic lye concentration works best for your recipes and your soaping style. Once you find that sweet spot, then you can deliberately vary the lye concentration a bit to best work with various recipes, decorative techniques, accelerating fragrances, and different additives.

I will give you some numbers that work well for me and the way I soap. Pretty much all of my cold process (CP) soaps are made with 30% to 33% lye concentration. If I want extra time for swirling or if I am using a naughty fragrance, I'll choose a 30% to 31% lye concentration. For a soap without any fancy stuff or for a recipe that naturally moves slowly, I would likely use 33%.

There are exceptions to my general rules of thumb --

... For a castile (100% olive oil) CP soap, I would use a 40% lye concentration to encourage the soap to trace faster
... For hot process (HP) soaps and liquid soaps (LS), I would use 25% lye concentration to allow for water evaporation and easier handling

Remember -- just a percent or two change in the lye concentration can definitely change how a soap recipe behaves. So you do not need to make big changes in the lye concentration to see definite differences.

For more information about using lye concentration rather than "water as % of oils", please see this thread:
http://www.soapmakingforum.com/showthread.php?t=54095

...and a related discussion about why curing is not just about evaporation that morphs into a discussion of water content:
http://www.soapmakingforum.com/showthread.php?t=56363

...and finally this detailed discussion:
http://www.soapmakingforum.com/showthread.php?t=53642

Geek Tip -- What are the SoapCalc numbers?

I've posted this elsewhere, but I'm adding this info to this thread too--

When evaluating a soap recipe, you can look at the individual amounts of each fatty acid (myristic, lauric, stearic, palmitic, oleic, ricinoleic, linoleic, linolenic, etc) to determine the effect of each fatty acid on the soap ... or you can use the SoapCalc "numbers" to do much the same thing.

Unfortunately beginning soapers often get confused because the names of the SoapCalc numbers are rather misleading. Another thing beginning soapers do is endlessly tweak a recipe to get certain numbers "just right." The thing to remember is the fatty acid profile and the SoapCalc numbers are just guidelines. They do not account for how the soap is made -- hot process, cold process, and all the variations. They do not account for the effect of superfat, water content, or cure time. And they do not account for the effect of any additives (sugar, milk, honey, sodium lactate, etc.)

I want to show you how the SoapCalc "numbers" are calculated, so you can use these numbers more effectively. To keep this explanation simple, I am going to choose a single fat -- cocoa butter -- and pretend as if I am going to make a soap from this fat.

Cocoa butter has a fatty acid profile that looks something like this:

Lauric 0
Myristic 0
Palmitic 25-35% (average is about 30%)
Stearic 28-38% (average is about 33%)
Ricinoleic 0
Oleic 29-41% (average is about 36%)
Linoleic 2-7% (average is about 4%)
Linolenic 0

Lots of numbers, right? Let's look at how SoapCalc groups those numbers into fewer bits of useful information:

Hardness 61
Cleansing 0
Condition 38
Bubbly 0
Creamy 61

So now, okay, how does a person translate from the fatty acid profile to the Soapcalc numbers? Here's how:

Hardness: The hardness value is the sum of Lauric + Myristic + Palmitic + Stearic acids.

These are the saturated fatty acids. The Hardness number is a measure of the physical hardness-like-a-rock. It tells you how relatively easy it will be to unmold a particular soap after saponification. It does NOT necessarily tell you how long-lived the soap will be -- I'll get to that in a bit.

Hardness number from the fatty acid profile (above) = 0% + 0% + 30% + 33% = 63%.
Soapcalc Hardness = 61%.

Is the difference between 63% and 61% important? Nope, not too much. Keep in mind that any fatty acid profile for any particular fat is only an estimate. The SoapCalc folks calculated their Hardness number from slightly different data than we are using. Bottom line -- don't agonize over differences of a few percentage points.

Cleansing: The cleansing value is the sum of Lauric + Myristic acids.

It is a measure of how water soluble the soap is -- meaning it is a measure of how easily the soap dissolves in difficult situations such as hard water, cold water, or salt water. The Cleansing number does NOT tell you whether the soap will actually get your skin clean, which is the usual misinterpretation of the Cleansing number. A soap with a Cleansing value of zero will clean your skin; it is just not as water soluble in hard/cold/salty water as a soap with a high Cleansing value.

The cleansing value is also a rough measure of how harsh the soap may be to the skin. The more lauric acid there is in the soap, the higher the cleansing value will be and the more likely the soap will be drying or irritating. People with sensitive or damaged skin are more likely to react to a soap with a high cleansing value than people with normal skin. That is a big reason why some folks are fine with 30% coconut oil in their soap recipes and others shudder at the thought of any coconut oil at all in their soap. Most of us fall somewhere in the middle, based on what many soapers report.

Cleansing number from the fatty acid profile = 0% + 0% = 0%
SoapCalc Cleansing = 0%

Conditioning: The conditioning value is the sum of Oleic + Ricinoleic + Linoleic + Linolenic acids.

These are the monounsaturated and polyunsaturated fatty acids. As the conditioning value goes up, the cleansing value goes down, and vice versa. Since the two are closely related, I focus on the cleansing value, since it has more influence on how my skin feels after bathing. I do not pay too much attention to the conditioning value.

Conditioning number from the fatty acid profile = 0% + 36% + 4% + 0% = 40%
SoapCalc Conditioning = 38%

Bubbly: The Bubbly value is the sum of the Lauric + Myristic + Ricinoleic acids.

This is a measure of how much loose, fluffy lather is produced. A "bubbly" lather is produced quickly by a soap, but doesn't last long.

Remember that the first two fatty acids make a soap that is very soluble in water, so it makes sense that a soap that has a lot of these two fatty acids would make lots of lather, right?

Ricinoleic acid does not make soap that lathers well on its own, but combined with other fatty acids, it enhances the lather the other fatty acids produce. Does a low or zero Bubbly number mean the soap doesn't lather at all? Nope -- just that the soap might not have a lot of fluffy big bubbles.

Bubbly number from the fatty acid profile = 0% + 0% + 0% = 0%
SoapCalc Bubbly = 0%

Creamy: The Creamy value is the sum of the Palmitic + Stearic + Ricinoleic acids.

Palmitic and stearic are the fatty acids that produce lather that is fine textured (like whipped cream) and longer lived. Ricinoleic, as mentioned before, enhances lather, whether it be big, bubbly lather or dense, creamy lather.

Creamy number from the fatty acid profile = 30% + 33% = 63%
SoapCalc Creamy number = 61%

Long life: The longevity of a soap is the sum of the Palmitic + Stearic acids.

Palmitic and stearic acids create a soap that is relatively hard and relatively insoluble in water.

Long-lasting number from the fatty acid profile = 30% + 33% = 63%
SoapCalc Long-lasting number = ???

I said I'd get back to this issue. SoapCalc numbers do not directly measure longevity. Many people confuse the Hardness number as being a measure of how long lived the soap is, but that is not strictly correct. If you are working in SoapCalc, the fastest way to estimate the Long-lasting number is this:

SoapCalc Long-lasting number = Hardness number - Cleansing number

For cocoa butter, it's a no-brainer -- the Hardness number is the same as the Long-lasting number. For a Coconut Oil soap, the story is quite different:

Hardness = 79
Cleansing = 67
Long-lasting = 79 - 67 = 12

Compare that to 63 for cocoa butter. Bottom line -- a coconut oil soap will not last nearly as long as a cocoa butter soap, all other things being equal.
 
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TeresaT

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About 0.77 gram of glycerin is produced for every 1 gram of NaOH used to make soap. The soap must have a zero to a positive superfat for this to be accurate.

Glycerin weight, grams = (NaOH weight, grams) X 0.77


As we know, I am not a mathematical genius or particularly scientifically savvy. So, that said, I soap at 8% SF. If I use 25 gm NaOH in a recipe, does that mean I can expect that recipe to yield 19.25 gm glycerin? The SF value doesn't matter? I just need to make sure I have enough lye to oils to completely react the lye?
 

galaxyMLP

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As we know, I am not a mathematical genius or particularly scientifically savvy. So, that said, I soap at 8% SF. If I use 25 gm NaOH in a recipe, does that mean I can expect that recipe to yield 19.25 gm glycerin? The SF value doesn't matter? I just need to make sure I have enough lye to oils to completely react the lye?
Teresa, glycerin is only produced when the NaOH can react with the fats. If you have a positive superfat then you have excess fat. But, for that tip/equation it doesn't matter.

Example:

Fat + Lye = Glycerin and Soap

If you have extra fat, you cant react it all and you are looking at:
Excess Fat + Lye =Glycerin, Soap, Fat

If you have extra lye, you are looking at:
Fat + Excess Lye= Glycerin, Soap, Lye.

Since the calculation is based on lye, if you use a negative super fat (excess lye) you will artificially increase the amount of glycerin you would expect using this equation. Fat is not factored into this equation so super fat has no perceived effect on the glycerin content because you're using a fixed lye amount that will react with a fixed amount of fat.
 

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