Substitutes for soap

Tallow substitutes in soap

Tallow is the harder of the two common animal fats, and in the bar below palm oil comes closest to it, then shea and cocoa butter half each, then mutton tallow. Lard is further off: a softer bar, 41 for hardness against 44, though its lye is the same within a fraction. Shea on its own takes less lye, so weighing the lye for tallow and using shea leaves the bar at 2.9 % superfat.

The bar they are tried in

Tallow35 %
Olive oil35 %
Coconut oil25 %
Castor oil5 %

NaOH · 1000 g · Superfat 5 % 141.0 g

The bar: 35 % tallow, at a 5 % superfat, for 1,000 g of oils. The rest: 35 % olive oil, 25 % coconut oil, and 5 % castor oil. As it is, it needs 141.0 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
1Palm oil	141.8	5.6 %recalculate
2Shea butter and cocoa butter, half each	139.1	3.7 %recalculate
3Mutton tallow	141.0	5.0 %barely moves
4Kokum butter	139.4	3.9 %recalculate
5Shea butter	137.9	2.9 %recalculate
6Lard	141.3	5.2 %barely moves
7Nothing in its place: olive oil takes its share	139.6	4.0 %recalculate

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: Lard vs tallow Tallow vs mutton tallow Tallow vs shea butter Palm oil vs tallow

What each does to the bar

	Hardness	Cleansing	Conditioning	Bubbly lather	Creamy lather	Iodine value	INS	Linoleic and linolenic acid, %
As it is, with tallow	44	18	51	23	30	52	156	7.0
Palm oil	43	18	54	22	30	54	155	9.0
Shea butter and cocoa butter, half each	44	17	52	21	32	52	154	7.0
Mutton tallow	46	18	50	22	33	49	159	6.3
Kokum butter	46	17	50	22	33	49	157	5.2
Shea butter	42	17	55	21	29	54	149	7.4
Lard	41	18	55	22	27	57	152	8.6
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: