Favourite Superfat?

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froggybean37

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Do you have a general SF you like to stick to? I tend to use 7% (most of my recipes use around 20-25% coconut oil) - wondering if this is higher, lower, or on par with most? What is the highest you have used with a batch (assuming it's not one with a higher-than-usual coconut oil content)?
 

Obsidian

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I generally do 8% SF with 20% coconut. I did make one batch with 25% SF just to see what it would be like but of course, I haven't used it yet.
 

DeeAnna

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I have been using 5% SF, but I am gradually edging my way to using a lower SF. My soap recipe calculator is also set to account for my NaOH being 97% pure, based on data from my supplier.

From what I gather, most calcs assume NaOH is 100% pure, which is never the case. That assumption adds another 3-4% of hidden superfat to most recipes. I don't think most soapers realize that.
 

LuckyStar

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I do about 7% has been my go to for a while my go to recipe uses 19% coconut oil.

I'm thinking of trying a 10-15% super fat just for kicks though.
 

KristaY

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Well shoot! DeeAnna, you're right on top of things, as usual. :p Again, thinking NaOH was 100% pure, I went to Essential Depot and looked at the Certificate of Analysis for food grade NaOH. Low and behold it's 96% minimum. Yet another "ballpark" figure to work with. Since it says "minimum" that leaves a 4% variable. Since we don't know the exact specification of each bottle we receive, we could end up with SF that's significantly different than planned (as you stated, DeeAnna). Now I'm starting to re-think SF. This could be another explanation for DOS appearing in some batches and not in others, couldn't it? By using oils prone to DOS and leaving more free due to a higher SF (more fats left un-saponified)? Just when I think I'm grasping the science, something comes along that throws it all out the window, lol!
 

DeeAnna

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"...By using oils prone to DOS and leaving more free due to a higher SF (more fats left un-saponified)?..."

That's what I suspect, but I know others feel differently. Kevin Dunn did an experiment with results that many people interpret to mean that superfat has no effect on DOS. I've read the study a number of times and interpret his results differently. My opinion is that lower superfat does not absolutely prevent DOS, but it may reduce the chance of DOS appearing, all other things being equal.

There are many other factors involved in DOS as well, however, so superfat is just one factor to consider. Some of the other possible triggers for DOS are the amounts of free fatty acids and other impurities in the fats, the mineral and metal content in the water and other ingredients, the way the soap is cured, exposure to light and humidity, etc.
 

DeeAnna

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Carolyn -- it's your experience and ideas that are encouraging me to go lower in superfat. Having tried some of your soaps, I can say they are quite nice. I doublechecked my last soap and it was at 4% superfat, adjusted for NaOH at 97% purity. It turned out well, and I will have no reservations about doing the recipe again at 3-4% SF.

"...Low and behold it's 96% minimum. Yet another "ballpark" figure to work with. Since it says "minimum" that leaves a 4% variable...."

Yep. Although I'll add some more to that to further confuse the situation, based on my experience as an engineer in chemical production. If the allowable purity for a chemical happens to be 96%, we would run the chemical production to produce 97-98% purity. That gives a cushion against a little variability, but, frankly, there's no point in shooting for better. It can be surprisingly difficult and expensive to run a chemical production facility to produce a product that is significantly more pure than the reasonable minimum.

Also keep in mind that that this 96% purity is for the material that is coming out of the manufacturer's door. When we get NaOH, it has been repackaged by the distributor into smaller containers and we open those containers a number of times in our soap kitchens as we make various batches of soap. All that handling causes some water vapor and CO2 to enter the container. NaOH ~will~ react with that water and CO2, thus lowering the purity a wee bit here and a wee bit there. By the time the NaOH hits the soap pot, I would bet the purity is not any much higher than the minimum on the certificate of analysis. By the time the last of the NaOH is poured out of its container, the purity is possibly even a bit lower.
 

LuckyStar

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Full disclosure, I used to soap at 3-5 % fairly often, but i was flat out laughed at and called a soap making novice by one of the other forums i used to be a part of. So i started upping it bit by bit. To be honest, i don't feel all that much of a difference one way or the other between a 5 or 8% super fat
 
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I knew about the purity of NaOH. I also know about the humidity where I live. The difference between soap made with a new bottle of lye and an old bottle is quite large. I have been compensating by using 5% when it is new, then dropping the superfat by 1% per quarter bottle.

I did, however, forget to account for that when I made laundry soap this weekend. I ended up with a separating soap. I just added 0.5 oz NaOH to 2 oz H2O, and added it a tablespoon at the time until I got the pH up to 10.5, and pulled the rest of the loose oil out with pipettes.
 

DeeAnna

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"... I have been compensating by using 5% when it is new, then dropping the superfat by 1% per quarter bottle...."

Nice! Thanks for sharing that, Susie. Very helpful.
 

judymoody

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5% dries out my skin (but my recipe is about 35% coconut because that's what DH likes). I use 8% most of the time and can make a soap that works for both of us.
 

froggybean37

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I'm so glad this opened up to be a thread with so much great advice! I was considering going up as high as 10% SF but not sure it's necessary with everyone's great knowledge. I may fiddle a bit more with my CO content instead to help with any "drying" feeling.
 

btz

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7% for me, but I lower it to 5% if I use additives like coconut milk which will up the SF anyway.
 

Meganmischke

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I find soap with a sf higher than 5% to be a bit on the soft side. Going over 8% I have found the soap doesn't last at all in the shower.
 

Miha Engblom

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My favourite SF for bars is 4%-5% for 30%CO and in liquid castille 2.5 %. I have been trying higher % before, but they gave me problems with the drain. I do not know if somebody would like to buy soap that stucks their drain and makes the sink dirty fast. For soap with a lot of butter I would not use more than 4 %. A long curing time will make them mild enough... just my opinion :D
 

jade-15

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Are there any drawbacks to having a high superfat?
I believe it can affect lather - a too high SF may 'dampen' the bubbles.
Plus the feeling of oils on skin, oils in drain... Not something I've personally experienced but just things I've picked up on the forums :)

I made 2 batches of the same soap recipes, but one with a 3% SF and one with 10%.
Could not tell the difference.
It was about then I realised the cleansing/conditioning aspects of the RECIPE were more important than the superfat and additives (well DUH haha).
So now I'm just sticking with 5-6 (I think).
 

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