# Is Glycerin Included When Calculating Superfat and scents?

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#### Pims

##### Member
If you add glycerin to your soap (as in a shaving soap for example) do you include the glycerin content when calculating superfat and scents?

For example, a recipe is:

Olive 100g
Palm 100g
Coconut 100g
Glycerin 25g

You want to add fragrance at 3% of oils...

Is that 3% of 300g or 3% of 325g?

#### DeeAnna

##### Well-Known Member
No to both questions.

Glycerin is not a triglyceride fat and it doesn't consume any lye, so it can't be a superfat. You only consider ingredients that saponify or otherwise consume some lye when determining the superfat.

Glycerin is sometimes called a "supercream" ingredient when it is added to cream soap, but supercream additives are not considered to be part of the superfat.

Most people base their fragrance on the weight of oils, so glycerin wouldn't be included in that calculation. So you'd use 3% of 300g.

#### wearytraveler

##### Well-Known Member
I don't mean to hijack the thread but with regards to measuring the FO based on oils only... shouldn't the percentage of FO be calculated based off of the total weight of all oils and liquids as they all make up what will eventually be the total weight/volume/mass of the soap? I may be doing it "wrong" or going against the grain (it's me, after all) but when I calculate the percentage of FO I use for any given batch I base the percentage based off of the total weight of the final product. Basically, I enter all values in Soapcalc and omit the FO. I get my total and then calculate the percentage then add the FO value to the recipe. Again, sorry for taking this in another direction... just curious.

#### IrishLass

Staff member
Moderator
I always calculate based on oil weight when soap-making. The reason I don't do it based on total weight is because a lot of the weight that makes up the total is water, most of which evaporates, which would leave a higher percentage amount of FO in my fully cured soap that if I had based it on the oil amount instead.

IrishLass

#### wearytraveler

##### Well-Known Member
Well THAT makes sense... and I didn't even need a pot of coffee to get it!

I always calculate based on oil weight when soap-making. The reason I don't do it based on total weight is because a lot of the weight that makes up the total is water, most of which evaporates, which would leave a higher percentage amount of FO in my fully cured soap that if I had based it on the oil amount instead.

IrishLass

Last edited:

#### DeeAnna

##### Well-Known Member
I know people do it both ways, but most calculate based off the total oil weight. You could make the argument that the NaOH weight doesn't evaporate any more than the oil weight does, but calculating on oil weight alone is just how most people do it.

The other benefit of basing the scent dosage on oil weight that people can have an intelligent discussion about it because this convention is so widely used.

If you make anything else -- lotions, for example -- then, yes, you'd want to calculate scent based on total batch weight. There should be basically no water evaporation from a lotion.

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