Substitutes for soap

Cocoa butter substitutes in soap

Cocoa butter’s hardness is an even mix of palmitic and stearic acid, and three seed butters match it best: kokum, illipe and sal each keep the bar below within a point of where cocoa butter had it, and none moves the lye enough to matter. Kokum and sal behave much like cocoa butter without its scent, but their fatty acids come from single analyses made in 1939 and 1978, so treat their closeness as approximate.

The bar they are tried in

Cocoa butter15 %
Olive oil55 %
Coconut oil25 %
Castor oil5 %

NaOH · 1000 g · Superfat 5 % 139.9 g

The bar: 15 % cocoa butter, at a 5 % superfat, for 1,000 g of oils. The rest: 55 % olive oil, 25 % coconut oil, and 5 % castor oil. As it is, it needs 139.9 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
1Kokum butter	139.5	4.7 %barely moves
2Illipe butter	139.6	4.8 %barely moves
3Sal butter	139.3	4.6 %barely moves
4Mango butter	139.7	4.9 %barely moves
5Tallow	140.2	5.2 %barely moves
6Palm oil	140.5	5.4 %barely moves
7Shea butter	138.9	4.3 %recalculate
8Nothing in its place: olive oil takes its share	139.6	4.8 %barely moves

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: Palm oil vs cocoa butter Shea butter vs cocoa butter Cocoa butter vs mango butter Cocoa butter vs kokum butter

What each does to the bar

	Hardness	Cleansing	Conditioning	Bubbly lather	Creamy lather	Iodine value	INS	Linoleic and linolenic acid, %
As it is, with cocoa butter	38	17	58	21	26	58	148	8.4
Kokum butter	38	17	59	22	25	58	148	7.8
Illipe butter	39	17	57	21	26	58	148	7.9
Sal butter	37	17	58	21	25	59	147	8.1
Mango butter	37	17	59	21	24	60	147	8.3
Tallow	37	18	59	22	24	60	147	8.6
Palm oil	37	17	60	22	24	61	147	9.4
Shea butter	36	17	60	21	23	61	144	8.7
Nothing in its place: olive oil takes its share	32	17	65	21	19	66	141	9.7
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: