@kdm, just to clarify neither Essential oils nor Fragrance Oils affect the amount of lye soap requires to saponify. Neither EO's nor FO's have any effect on SuperFat.
3% SF (I don't understand this setting - HELP!)
A bit more on SuperFat, if it helps.
Super Fat means more fat than the amount of lye used in the formula to make the soap. SF is excess oil in soap after saponification occurs.
By setting the calculator to 3% SF, that means your soap will have an excess of fat at the rate of 3% of total oils in your formula (IF your calculator's SAP numbers are correct for the oils you actually use, which is possible, but not necessarily 100% guaranteed due to variables with crops that become the oils.)
As a point of interest regarding superfat: A minor lye heavy soap will eventually loose that excess lye via the interaction of the NaOH (sodium hydroxide) molecules with oxygen as the soap cures. The excess lye becomes Sodium Carbonate which is what is in washing soda. It will form on the surface of the soap as it cures and we call it soda ash when it forms on the surface of soap. It is harmless on the surface of the soap and will wash off with use. It does, however, mute the colors & designs on the surface of the soap, so some soapers remove the ash using methods you can read about in this
link.
Woow. Rewind. Did you say glycerin? I have gallons of that. Can I put it in soap?
Be careful adding glycerine to bar soap, as too much will make rubbery soap, and unfortunately it does not evaporate out like too much water does. As a humectant, it just draws moisture to the bar.
You can use glucerin for mixing colorants, but when you do, use it sparingly (for the above reason). I speak from experience.
Out of curiosity, why do you have gallons of glycerine? If there is going to be a shortage, you may end up being in good shape if you want to make glycerine soap. (Melt & Pour glycerine soap from scratch, or Liquid Glycerine soap).