Ohhh DeeAnnnnnaaaaa! Come out and play!

[DeeAnna]

"...So, it's 100% minus the percentage we want to not be saponified, is the percentage of lye used in our base recipe. NOT 100% plus an additional percentage. ..."

Yep, I agree. You hit the nail perfectly on the head, Grayce. But it's awfully hard to explain in a way that is clear to others, isn't it???

 

[MzMolly65]

So we have to find the lye amount for the base oils instead, which will only be the 92% of the total lye amount. Once we know THAT lye amount, we can find out how much the 8% of the lye amount is to make up the full 100%. Once we know that 8%, then we can see how much oil that will saponify.

So, it's 100% minus the percentage we want to not be saponified, is the percentage of lye used in our base recipe. NOT 100% plus an additional percentage.

CHA-CHING!!! Some things were clicking but THAT was the magic statement that unlocked the door. Thank you, thank you, thank you. I will still need to read through all of this over and over until I really understand but my brain just gave a sigh of relief so I will let it all sink in slowly before going back and reading it all again.

Everyone who tried to explain is brilliant and I must say, what a team effort. Thank you all.

 

[DeeAnna]

It's fascinating (and frustrating!) how one person can explain a concept a certain way and some people will understand the explanation perfectly, but others don't. Then someone else explains the same thing but in a slightly different way and the rest get it perfectly. Or an explanation doesn't make sense at one moment, but it does a little while later.

I'm glad you finally had your "aha -- eureka!" moment today!

 

[grayceworks]

DeeAnna, YOUR explanations and writing out the equations differently and making that chart are what helped me figure out how to wrap my mind around that little point that was bugging me! so that i could reread the CS page and that one part of the equation finally made sense. And once I could fit that in to the picture, that is what helped me come up with my part of the explanation.

 

[The Efficacious Gentleman]

I just tried this. My issue is that I then have little control over my batch size - if I want to make a 1000g batch, I can't just make an amount smaller until I have the right lye amount, or I have less oil than I want for my batch.

If I calculate a 2% SF batch, make it, cook it and then add some more oil to the finished, lye free soap - why do I need to work out how much lye would have been needed to saponify it but then take some away from it?

 

[grayceworks]

Because you don't know how much SF oil you need, but you do know how much lye you need to saponify your desired SF percentage. Because you know the lye amount to saponify the batch without the SF oil.

So you have the lye amount without the SF oil. That is the bigger percentage of your total batch. Your total batch will be your base oils plus SF.

You use that lye amount from the KNOWN amount of oils, and use it to find out how much more lye is needed to do the complete batch. Which is the base + SF. You do this by finding the total lye amount. And then the total lye amount, minus the lye amount you'll use to saponify your base oils, equals how much lye is needed for your SF oil.

Now that you know that lye amount, you can divide it by the SAP of any of your desired SF oils, and get the ounces or grams of oil you will need to achieve that SF percentage.

So like in the example I gave, you had enough oils for your main oils that you'd need 4.07oz of lye at 1%SF. and I decided I wanted to SF at an additional 8%. So I have my initial lye amount, and I divide it by .92 to get the lye amount it would need for the main oils plus the SF.

When I subtract the lye amount for my main oils, from this lye amount for the total batch, it gives me the lye amount that would saponify the percentage of oils for SF that I chose.

So that number gets divided by the SAP of the oil, and gives me the amount of oil needed to SF that batch.

By doing it this way, you are not limited in batch size. All you have to know is your initial lye amount for the main oils of your recipe, no matter the size. Once you know that, you just go a step at a time and end up with the amount of oil you need for SF.

 

[The Efficacious Gentleman]

Are we talking HP or CP?

 

[grayceworks]

Are we talking HP or CP?

HP. Otherwise there's no point to figuring out an exact amount of a specific oil, you'd just figure them all in together and let soapcalc figure a discount on the lye.

 

[The Efficacious Gentleman]

HP. Otherwise there's no point to figuring out an exact amount of a specific oil, you'd just figure them all in together and let soapcalc figure a discount on the lye.

That's what I was thinking! Gah, I am smarter than this, I know it! Unless it's just that I'm doing it a different way:

So I know that I want to make a 1120 gram batch with 15% CO, 40% Palm, 10% Rapeseed, 15% OO, 15% Pumpkin and 5% Castor. (count count count, Yep, 100%!) I want to do a 10% SF with most of that being Pumpkinseed.

So I put that all in to soap calc and it gives me the weights for each oil. I take the weight of the pumpkin at 15% (168g) and work out what that would be at 7% instead (78.4,g so we say 78g) a difference of 90grams.

I then switch soap calc over to work on the weight not the % and put the pumpkin seed at 78g and the SF at 2%, leaving all others the same. I now have a smaller batch at 1030grams, which is fine as it is 1120 minus the pumpkin at 90 grams.

The amount of lye in the calc will be for this batch at 2% SF and then when I add in my 90grams Pumpkin after cook, I'll be at 1120g oils, 10% SF with most of it being pumpkin.

Or am I a pumpkin? :crazy:

 

[grayceworks]

That's what I was thinking! Gah, I am smarter than this, I know it! Unless it's just that I'm doing it a different way:

So I know that I want to make a 1120 gram batch with 15% CO, 40% Palm, 10% Rapeseed, 15% OO, 15% Pumpkin and 5% Castor. (count count count, Yep, 100%!) I want to do a 10% SF with most of that being Pumpkinseed.

So I put that all in to soap calc and it gives me the weights for each oil. I take the weight of the pumpkin at 15% (168g) and work out what that would be at 7% instead (78.4,g so we say 78g) a difference of 90grams.

I then switch soap calc over to work on the weight not the % and put the pumpkin seed at 78g and the SF at 2%, leaving all others the same. I now have a smaller batch at 1030grams, which is fine as it is 1120 minus the pumpkin at 90 grams.

The amount of lye in the calc will be for this batch at 2% SF and then when I add in my 90grams Pumpkin after cook, I'll be at 1120g oils, 10% SF with most of it being pumpkin.

Or am I a pumpkin? :crazy:

Ok, so you've taken a portion of the pumpkin oil out to save for after the cook. Your new base oils add up to the 1030g as you stated. The amount of lye required for these oils at 2% lye discount is 146.136g.

You want to have approximately a 10% SF, and you've already taken care of part of that with your 2% discount on the lye. So we're just going to pretend that's 0 and that we want an 8% SF , because I'm to brain-dead right now to make it more precise and it'd only change it a fraction of a gram anyhow lol.

So we take the 146.136g of lye, and divide it by .92 to get how much lye it would take if you were saponifying everything. Because the 146g of lye is 92% of the total lye amount for everything. That gives us 158.84g. We just want to know the difference between how much you'll use for your base oils and how much you'd use for everything. Because we don't want to use all the lye, we want to leave that 8% out and only use the 92% of the lye.

The difference is 12.7g. That 12.7g is the other 8% of the lye needed for everything. Using that, we can figure out how much oil it will saponify.

So that SAP value of the pumpkin seed oil is .139

So 12.7 divided by .139 says we need 91.4g of pumpkin seed oil to make your extra 8% SF after the cook. Along with your existing oils and lye discount of 2%, that gives you 1121.4g total batch size, with lye amt that you figured originally of 146.136g, for approximately 10% SF.

So either way is within a gram of each other. I'd say you've
got it down!

 

[MzMolly65]

Or am I a pumpkin? :crazy:

After reading all that .. *I* am pumpkin .. mush!

 

[The Efficacious Gentleman]

If it isn't poo-poo'd from a science perspective, I find my method much easier as I don't have to think about lye calculations for things that will never be, plus I can use the Soap Calc to do all the hard stuff for me

 

[MzMolly65]

OK Gent .. after reading your theory several times it's actually starting to make sense to me. Let me know how that works for you and maybe I'll do it that way .. if it's not poo-poo'd!

I'd experiment myself but I'm living vicariously through others until I can walk again :-(

 

[The Efficacious Gentleman]

Again, if it's isn't Poo-poo'd, I think there is an easier step in there, too -

When I had all my oils, including 15% pumpkin, in my calc in percent mode, I could have just reduced the pumkpin down to 7% in the calc and added any other oil (say, Canola just to pick one) at 8%. This oil is just so that we can get the weight sorted, it has nothing to do with the lye!

I then write down the weight of the canola - this will be how much pumpkin I add in at the end. Switch the calc over to weight mode and then remove the canola. Set the SF to 2% and calculate - you now have lye for the 2% batch AND you have the exact amount of SF to add in after the cook.

Ooooooooooh, I really hope this is actually right, as it is so much easier for me to understand than the other way :wtf:

 

[grayceworks]

I see where you're going with it, and it would work as long as your 'placeholder' oil has the same SAP as the oil it's representing.

Basically, you're using an oil to hold the SF oil's place, and then figuring your 10% SF, right? And then taking that oil out and getting your 2% lye discount amount right? Those 2 lye numbers should match.

Alternately, if you used your placeholder oil and set the SF at 2% while that's still in the recipe,
And then take it out and calculate again at 2%
And subtract those 2 lye numbers, and divide by the SAP of your SF oil, THAT amount of OIL should match the amount of oil you put as your SF oil above.

They're all doing the same math, just starting at different starting points of the equation.

Because it all boils down to how much lye is needed to saponify everything, and then how much do we discount it to get the amount of unsaponified oils that we want.

The difference between how much to do everything, and the discounted amount, tells us how to find the right amount of oil.

Because if you're wanting to SF with something that has an oddball SAP value like jojoba, you can't plug in a placeholder oil. You gotta figure the total lye, the discounted amount, find the difference, and divide by the SAP to get the weight of oil in that case.

It might be easier in that instance though to use soapcalc to still do most of the math, like where I said 'Alternately' above...

 

[DeeAnna]

Gent -- I am not quite convinced you've gotten the right of it. I am pretty sure you are using the superfat as a % of the oils method (Songwind and my method) rather than the superfat as % of lye method (Grayce and CS's method). It turns out the final answers with both methods are essentially the same for your particular recipe, but I don't think this will hold true for all recipes.

Here's how I would do it:

"...1120 gram batch with 15% CO, 40% Palm, 10% Rapeseed, 15% OO, 15% Pumpkin and 5% Castor.... I want to do a 10% SF..."

Using the info from above, your FINISHED recipe is this:

Coconut Oil 168 g
Palm Oil 448
Rapeseed Oil 112
Pumpkin Seed 168
Castor 56
Olive 168
Totals 1120 g

The lye weight is 145.5 g for the FINISHED recipe at 10% superfat.

Now find the SOAPING recipe. Change soapcalc from % to grams. Lower the superfat from 10% to 2%.

How much LESS pumpkinseed is needed in your SOAPING recipe at 2% superfat to use the SAME amount of lye at 145.5 g?

I reduced pumpkinseed to 1 gram (can't put a zero into a soapcalc recipe). Lye was much too low.
Increased pumpkinseed to 50 g. Lye is still too low.
Increased to 60 g. Ditto.
Increased to 70 g. Ditto.
Increased to 80 g. Too high.
Reduced to 75 g. A bit too low.
Increased pumpkinseed to 77 g. About right -- lye weight is 145.45 g.
Stop there.

Your SOAPING RECIPE is:

Coconut 168 g
Palm 448
Rapeseed 112
Pumpkin 77
Castor 56
Olive 168
Total 1029 g

Your 8% PUMPKINSEED SUPERFAT is:

168 - 77 = 91 g

This answer is about the same as your method, but I am concerned that this may be a happy coincidence.

 

[DeeAnna]

I'm going to analyze the same recipe, but substitute meadowfoam seed oil for pumpkin seed oil. Meadowfoam has a sap value of 0.120 vs pumpkin seed sap value of 0.139 -- a big difference. Let's see if the "superfat as % of lye" method gives a different answer compared with the "superfat as % of oils" method.

****

"Superfat as % of lye" method: How much added meadowfoam would react with 8% of the lye in the recipe? Use this oil weight as the final HP superfat.

The FINISHED recipe will be this:

Coconut Oil 168 g
Palm Oil 448
Rapeseed Oil 112
MEADOWFOAM 168
Castor 56
Olive 168
Totals 1120 g

The lye weight is 142.7 g for this FINISHED recipe at 10% superfat.

Now find the SOAPING recipe. Change soapcalc from % to grams. Lower the superfat from 10% to 2%.

How much LESS meadowfoam is needed in the SOAPING recipe at 2% superfat to use the SAME amount of lye at 142.7 g?

Omitting all the trial and error, the SOAPING recipe needs 61 g of meadowfoam.

Coconut 168 g
Palm 4480.12 vs
Rapeseed 112
Meadowfoam 61
Castor Oil 56
Olive Oil 168
Totals 1013 g

The meadowfoam SUPERFAT is this:

168 - 61 = 107 g

****

"Superfat as % of oils" method: What is 8% of the total oil in the finished recipe? Use this as the final meadowfoam superfat.

0.08 * 1120 g = 90 g

Big difference between the two methods!

 

[grayceworks]

Exactly! You'd possibly end up lye-heavy in the soaping recipe, so that after you cooked, there would still be unreacted lye to eat up any SF you add after, defeating the purpose!

With such variation in SAP values, you really need to know how much a specific percent of your total lye needed is, so that you can find out how much oil that specific amount will cover. Because pumpkin seed and meadowfoam and jojoba and coconut all require different amounts of lye to cover the same weight in oil.

You have constants -- your base soaping oil weights, and how much lye is needed for those. Those are not changing regardless of how much weight of SF oil you end up with.

That lye amount is discounted from the FULL version. So you DO need to know the full lye amount, even if ultimately you're not going to use all that lye, see? Because that full amount is what is discounted for your soaping amount.

You are not adding lye to your soaping version, you're taking lye away from the full final version for it to be superfatted.

 

[DeeAnna]

I am sorry this is so complicated, guys. Either Grayce's math method or my trial-and-error method are just not straightforward to do. Again, I wish there was a super easy way, but there's not.

 

[grayceworks]

1) input your recipe in soapcalc at 0 or 1 or 2 percent SF. This is what you will cook, with the amount of lye shown in this step. (If you chose 1 or 2, we are pretending that is YOUR 0% because that is where you feel safe with it.)

2) decide how much SF you want in percents. Convert to decimals. Ex- 8% becomes .08

3) the percent in step 2 is the amount of lye that was/will be discounted in order to reach the amount you already know from step 1.

4) this means that the amount in step 1 is the remaining part of the 100%. So if you are wanting to SF 8% (discount the lye by 8%) then the lye from step 1 is the other 92% of it that is NOT being discounted. And converted to decimals, that is .92 (sub in your own SF numbers in 2 thru 4 of course)

5) this means if you take the amount from step 1, and divide it by the decimal in step 4, you now know what 100% is.

6) because you know what 100% is on your lye, you can now find out what 8% lye is, by subtracting step1 from step 5. This little bit of lye is the amount you will have discounted when all is said and done.

7)Write this little lye number on THIS RECIPE. As long as THIS RECIPE does not change, this little bit of lye doesn't change either, and you can use this number to figure out LOTS of different SF oil amounts. How much shea is 8% ? How much coconut? How much avocado? Etc. You only need this little number here to figure the amounts for any of them!

Of course you could just do step 1 all by itself and have a low superfat recipe, or you could add oil afterwards willy-nilly and not know for sure how much SF there us, but if you want to know specifically how much of a specific oil will SF your recipe in step1 by the amount you chose in step 2, then you need to know exactly how much lye is being discounted.

7) that tiny bit of lye you are discounting will saponify a specific amount of oil. Different oils have different weights and different SAP values.

8 ) find the SAP value for the oil you want.

9) divide that little tiny lye amount by the SAP. Voila! You have your exact oil amount. This is how much oil that discounted lye would eat up if you didn't discount it.

So that's why you need to find 100% first in order to find 8% of 100%.

Otherwise it's a lot of guessing and fiddling.

But once you know what 5% or 8% or 10% lye is for a recipe, write it down, and then you can jump straight to step 8 if you're not changing anything but the SF oil type. It makes it very simple then to vary a recipe just by changing out the SF oil.