Preferred lye concentrations


Help Support SoapMakingForum:


Well-Known Member
Sep 14, 2016
Reaction score
Your preferred lye concentration?

Some i have read they do 25% lye concentration and other's up to 33%.

I have been doing it at 30% just to keep it easy. But what is the purpose of having a higher or lower lye concentration.

Also on soap calc what does "water as % of oils" mean and how is that different to lye concentration.

Thank you and sorry for all the questions!

The Efficacious Gentleman

Lifetime Supporter
Nov 19, 2013
Reaction score
Lye concentration is literally the amount of lye and water being linked. Water as % of oils links the water amount to the oils regardless of lye amount - so if you use a 20% or 0% lye discount, your water amount wouldn't change. This can have a big impact on the actual concentration.

Concentration is easier to control then for certain instances. I have no one concentration that I use as certain instances need a different concentration. Making a 100% olive oil soap benefits from a stringer solution than when making a 100% coconut oil. But for general soaps I use a 33% solution


Well-Known Member
Sep 19, 2015
Reaction score
Sth Coast, NSW, Australia
A lower lye concentration will trace slower and give you more time to work with it if you are adding colours and swirls.
So 27% will trace slower than 40% lye concentration.
Last edited:


Staff member
Feb 11, 2008
Reaction score
Right here, silly!
My preferred lye concentration for about 98% of my batches is 33%. I call it my 'Goldilocks' concentration because it's 'just right' for the majority of my batches. With it, I have enough time to do lots of lovely swirls (provided my FO is well-behaved), but trace is not an obnoxiously long time in coming. I would say that I'm usually able to bring my soap to a medium-thick trace and have it nicely molded within about 10 minutes of having added the lye to my oils, which is plenty enough 'working' time for me. And my finished soap cures without warping, which is always nice.

For the other 2% of my batches, the concentration varies depending on the formula and/or my FO. For example, if I'm making a 100% OO soap, which can take forever and a day to trace at a lower lye concentration, I'll bump it up to a 40% lye concentration. And/or if I am using an ornery accelerating FO, I'll go the opposite route and use a 30% or lower concentration so that things don't move too fast.

Using the 'water as % of oils' box on SoapCalc is not exactly the best way in which to decide how much water to use for one's batch. If I may quote our DeeAnna (who says it best):

DeeAnna said:
"water as % of oils" causes the water amount to vary, depending on the saponification value of the oils. A recipe using "water as % of oils" will have a less concentrated lye solution when using fats with lower sap values (say olive) and a more concentrated lye solution for fats with higher sap values (say coconut).

This is exactly the opposite of what you might want. For example, olive oil saponifies slowly with a more dilute lye solution. It does best with a moderate or even a more concentrated lye solution. Coconut oil needs no help to saponify quickly, so it may be desirable to have more water with a high CO recipe to have more working time and to minimize overheating.

IrishLass :)