Substitutes for soap

Coconut oil substitutes in soap

Coconut oil is the bar’s cleansing and big bubbles: about half lauric acid, which only another lauric oil replaces. Babassu and palm kernel oil are the ones soapmakers use in its place, and in the bar below they keep hardness, cleansing, conditioning and lather within two points; each needs a little less lye, so recalculate. Leave coconut oil out and the cleansing falls from 17 to 0, and the lye weighed for it would leave the bar lye-heavy, at −3.4 % superfat.

The bar they are tried in

Coconut oil25 %
Olive oil50 %
Shea butter20 %
Castor oil5 %

NaOH · 1000 g · Superfat 5 % 138.6 g

The bar: 25 % coconut 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 138.6 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
1Cohune oil	138.3	4.8 %barely moves
2Babassu oil	137.6	4.3 %recalculate
3Palm kernel oil	136.7	3.6 %recalculate
4Nothing in its place: olive oil takes its share	127.4	−3.4 %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 babassu oil Coconut 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 coconut oil	37	17	59	21	25	59	146	8.4
Cohune oil	36	16	60	20	25	60	144	8.4
Babassu oil	37	17	61	21	25	61	143	8.9
Palm kernel oil	37	17	61	21	24	61	140	8.5
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

The soaping oils: what each one brings to a bar

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: