Substitutes for soap

Palm kernel oil substitutes in soap

Palm kernel oil is a lauric oil pressed from the seed of the oil palm, and babassu replaces it best in the bar below, then cohune and coconut oil. Babassu is also the one that keeps a bar palm-free. All three take a little more lye than palm kernel oil, so weighing the lye for it and putting in coconut leaves the bar at 6.3 % superfat instead of 5 %: more oil left over, which is the safe way round.

The bar they are tried in

Palm kernel oil25 %
Olive oil50 %
Shea butter20 %
Castor oil5 %

NaOH · 1000 g · Superfat 5 % 136.7 g

The bar: 25 % palm kernel oil, at a 5 % superfat, for 1,000 g of oils. The rest: 50 % olive oil, 20 % shea butter, and 5 % castor oil. As it is, it needs 136.7 g of sodium hydroxide.

Open the bar in the lye calculator

The substitutes, closest first

Substitute	Sodium hydroxide, g	With the lye left as it was
1Babassu oil	137.6	5.6 %recalculate
2Cohune oil	138.3	6.1 %recalculate
3Coconut oil	138.6	6.3 %recalculate
4Nothing in its place: olive oil takes its share	127.4	−1.9 %lye-heavy: never swap without recalculating

With the lye left as it was: the superfat when the sodium hydroxide weighed for the bar as it is goes in with the substitute, planned at 5 %. Each lye figure opens that bar in the lye calculator, which works out the lye for it.

Side by side: Coconut oil vs palm kernel oil Babassu oil vs palm kernel oil

What each does to the bar

	Hardness	Cleansing	Conditioning	Bubbly lather	Creamy lather	Iodine value	INS	Linoleic and linolenic acid, %
As it is, with palm kernel oil	37	17	61	21	24	61	140	8.5
Babassu oil	37	17	61	21	25	61	143	8.9
Cohune oil	36	16	60	20	25	60	144	8.4
Coconut oil	37	17	59	21	25	59	146	8.4
Nothing in its place: olive oil takes its share	22	0	77	4	26	78	110	11.2
Usual range	29–54	12–22	44–69	14–46	16–48	41–70	136–165

Closest means the smallest total change across these figures, each counted against the width of its usual range, as the lye calculator’s swap suggestions count it. It is a convention, not a verdict on the bar: a butter that matches on paper can still melt lower, crack or smell, which the note above and the guides cover.

Guides

Substitutes for other oils

Where these numbers come from

Every figure here is worked out from the oil records, each with its sources on its own page: