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Goat milk soap base

Three pale cream goat milk soap bars beside a small glass bottle of milk and a dish of shea butter on a blue backdrop

Our plain milk soap: olive, coconut, palm and shea with frozen goat milk as all of the liquid, the lye added slowly and the loaf kept cold so it stays cream rather than tan. Unscented, and a base to build your own milk soaps on.

Skill
Intermediate
Method
Cold process
Batch
1000 g of oils about 1437 g of batter
Hands-on
1 hour
Cure
6 weeks
Gel phase
No keep it cool
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What you need

For 1000 g of oils, which fills a 1.5 litre loaf mould. Weigh everything, liquids included.

Olive Oil · 40.0 % 400 g 14.11 oz
Coconut Oil · 25.0 % 250 g 8.82 oz
Palm Oil · 25.0 % 250 g 8.82 oz
Shea Butter · 10.0 % 100 g 3.53 oz
Sodium hydroxide (NaOH) · the lye, 100 % pure 139.6 g 4.92 oz
Goat milk, frozen in cubes · all of the liquid; the lye goes onto it 298 g 10.51 oz
Superfat
6 %
Temperatures
Keep the milk and lye below 30 °C (86 °F) and soap with the oils at 25 to 30 °C (77 to 86 °F)

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Method

  1. Freeze the milk

    The day before, weigh 297.9 g goat milk into an ice-cube tray and freeze it solid. Cubes melt evenly as the lye goes in; a solid block does not.

  2. Get ready

    Put on splash goggles, nitrile gloves and long sleeves and open a window. Set out a 1.5 litre loaf mould, clear a shelf in the fridge or freezer for it, and make an ice bath: a bowl of ice and water that a heat-safe polypropylene jug can stand in.

  3. Weigh the oils and lye

    Melt the whole tub of palm oil and stir it well, then weigh 250 g of it with 250 g coconut oil and 100 g shea butter into the pot. Weigh 400 g olive oil into a jug and 139.6 g sodium hydroxide into a small, dry container.

  4. Melt the solid oils

    Warm the pot gently until the coconut oil, palm oil and shea butter are just clear, stir in the olive oil, and let the oils cool to 25 to 30 °C (77 to 86 °F).

  5. Add the lye to the milk

    Put the frozen milk cubes in the jug and stand it in the ice bath. Sprinkle in a spoonful of lye and stir until it has dissolved into the melting milk before adding the next, taking 10 to 15 minutes over it and keeping the mix below 30 °C (86 °F). It should end up pale yellow and smell faintly of ammonia.

  6. Strain and blend

    Pour the milk and lye through a stainless steel sieve into the oils, which catches any curds and shows you no lye is left undissolved. Stick blend in short bursts, stirring between them, until the batter reaches light trace.

  7. Pour and chill

    Pour into the mould, tap it on the worktop to release air, and put it uncovered in the fridge or the freezer for 24 hours, so the loaf never heats into gel and browns the milk.

  8. Clean up with your gloves on

    Wipe the raw batter off the pot and tools with paper towels into the bin, then wash everything in hot soapy water.

  9. Unmould and cut

    Let the loaf come back to room temperature before you unmould it, or moisture condenses on the cold soap. An ungelled loaf takes a while to firm up, so wait until it is firm, usually 24 to 48 hours after pouring, then unmould it with gloves on and cut it into bars.

  10. Cure

    Stand the bars on a rack with air around them for four to six weeks, turning them now and then. The ammonia smell fades in the first week or two.

Tips

  • Expect cream to pale yellow bars that drift a shade darker as they cure. Light tan all through means the milk warmed while the lye went in; a darker centre with a paler rim is partial gel, and only cosmetic.
  • If the milk and lye thicken like custard, the mix is too cold: stir it, let it warm a few degrees and carry on.
  • Other milks work the same way, but let the calculator weigh them: each carries its own share of water and fat, and cream or coconut milk bring enough fat to change the superfat a lot. Our milk soap guide compares them.
  • To scent it, stir essential oils in at light trace, as our lavender goat milk bar does. For a palm-free milk soap, that bar and our goat milk, oat and honey bar are written out in full.

Why make it

Milk soap is ordinary soap with milk in place of the water, and this is our plain base for it: goat milk as all the liquid, kept cold so the bar stays pale. The oils make a balanced bar, hardness 44, cleansing 17 and conditioning 53, and the milk's fat lifts the effective superfat to about 7 %. Makers often choose goat milk soap for dry or sensitive skin, but that reputation rests on experience rather than trials. The chemist Kevin Dunn found that milk's fat simply becomes soap, its sugar browns in the lye and its protein curdles, and we know of no controlled study showing that a milk soap is gentler than the same soap made with water. One caution belongs with it: two clinical reports describe people with eczema who became allergic to goat milk as a food after using goat milk skin products.

Sources

What tradition, makers' experience and research say about soaps like this, each labelled for what it is. It is not medical advice, and no soap treats a skin condition: if you have one, ask a doctor or pharmacist.

What the numbers say

  • Lauric acid 12.4 %
  • Myristic acid 5.0 %
  • Palmitic acid 18.9 %
  • Stearic acid 7.2 %
  • Oleic acid 44.2 %
  • Linoleic acid 8.6 %
  • Other 5.0 %

Saturated : unsaturated 47 : 53

Hardness 44 29–54
Cleansing 17 12–22
Conditioning 53 44–69
Bubbly lather 17 14–46
Creamy lather 26 16–48

Computed from the fatty acids of the fats above. The bands are what the craft has settled on, not chemistry — a bar outside one is not wrong.

Try it differently

20 variations

The same soap with one thing moved. Each opens in the calculator ready to change again.

From the guides

All guides
Intermediate 15 min read

Milk soap: goat milk, freezing and keeping it pale

How to make goat milk soap without scorching it: frozen milk, lye added a spoonful at a time, a cool mould, and a full recipe worked through the calculator.
Beginner 7 min read

Gel phase: to insulate or keep it cool

What gel phase is, why a loaf turns dark and translucent, how gelled and ungelled bars differ, why partial gel is cosmetic, and how to cause or prevent it.
Advanced 14 min read

Heat in soapmaking: lye solution, soaping temperature and gel

How hot a lye solution gets and why; where a loaf's own heat comes from; what decides gel; and safe temperatures for milk, sugar and melt and pour.

Where these proportions come from

Our own formulation: olive, coconut, palm and shea at a 6 % superfat, with goat milk as the whole liquid. The milk is a process choice rather than an oil, so the oils define the recipe; the method is the one milk-soap makers have used since the 1990s: frozen milk, the lye added a spoonful at a time, and the batch kept cool so the milk sugars do not scorch.

Formulation adapted from Making Natural Milk Soap (excerpted from Milk-Based Soaps) by Casey Makela (Storey Publishing, 1999). The method and notes are ours.

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