Substitutes for soap

Lard substitutes in soap

Lard makes a hard, white bar with a creamy, low lather, and for a bar without it the numbers point to shea butter first, then palm oil and tallow. Shea takes noticeably less lye: weigh the lye for lard and use shea, and the bar below drops to 2.6 % superfat, so recalculate. Palm oil and tallow barely move it. Vegetable shortening, lard’s stand-in in the kitchen, comes out softest of the fats, 35 for hardness against 41.

The bar they are tried in

Lard35 %
Olive oil35 %
Coconut oil25 %
Castor oil5 %

NaOH · 1000 g · Superfat 5 % 141.3 g

The bar: 35 % lard, 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 141.3 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
1Shea butter	137.9	2.6 %recalculate
2Palm oil	141.8	5.3 %barely moves
3Tallow	141.0	4.8 %barely moves
4Shea butter and cocoa butter, half each	139.1	3.5 %recalculate
5Vegetable shortening	140.2	4.2 %recalculate
6Nothing in its place: olive oil takes its share	139.6	3.8 %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 Lard vs vegetable shortening Lard vs shea butter Palm oil vs lard

What each does to the bar

	Hardness	Cleansing	Conditioning	Bubbly lather	Creamy lather	Linoleic and linolenic acid, %
As it is, with lard	41	18	55	22	27	8.6
Shea butter	42	17	55	21	29	7.4
Palm oil	43	18	54	22	30	9.0
Tallow	44	18	51	23	30	7.0
Shea butter and cocoa butter, half each	44	17	52	21	32	7.0
Vegetable shortening	35	17	62	22	22	15.7
Nothing in its place: olive oil takes its share	32	17	65	21	19	9.7
Usual range	29–54	12–22	44–69	14–46	16–48

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: