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Shampoo bars

Shampoo bar for normal to oily hair

Three pale cream shampoo soap bars beside half a lemon, a sprig of rosemary and a few lavender stems on a cobalt blue backdrop

A lathery soap shampoo bar for normal to oily hair: olive and coconut oils with a fifth castor oil and a little jojoba, shea, sweet almond, apricot kernel and avocado, scented with lemon, lavender and rosemary. It partners our kukui and almond shampoo bar for normal to dry hair; use either with an acid rinse.

Skill
Intermediate
Method
Cold process
Batch
1000 g of oils about 1447 g of batter
Hands-on
1 h 15 min
Cure
6 weeks
Gel phase
Yes insulate the mould
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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 · 41.0 % 410 g 14.46 oz
Coconut Oil · 28.0 % 280 g 9.88 oz
Castor Oil · 20.0 % 200 g 7.05 oz
Jojoba Oil · 3.0 % 30 g 1.06 oz
Shea Butter · 2.0 % 20 g 0.71 oz
Almond Oil · 2.0 % 20 g 0.71 oz
Apricot Kernel Oil · 2.0 % 20 g 0.71 oz
Avocado Oil · 2.0 % 20 g 0.71 oz
Sodium hydroxide (NaOH) · the lye, 100 % pure 137.7 g 4.86 oz
Distilled water · for a 33 % lye solution 279.7 g 9.86 oz
Cider or white vinegar (5 %), for the acid rinse · stirred into a mug (250 ml) of water for each wash; ¼ tsp of citric acid does the same job. Used on the hair, not in the soap 1 tbsp
Lemon essential oil · 1.5 % of the oils, at trace 15 g 0.53 oz
Lavender essential oil · 1.0 % of the oils, at trace 10 g 0.35 oz
Rosemary essential oil · 0.5 % of the oils, at trace 5 g 0.18 oz
Superfat
5 %
Temperatures
Oils and lye solution at 30 to 35 °C (86 to 95 °F), on the cool side because castor oil speeds trace

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Method

  1. Get ready

    Put on splash goggles, nitrile gloves and long sleeves, open a window or switch on the extractor fan, and keep children and pets out of the kitchen. Line a 1.5 litre loaf mould.

  2. Weigh the oils

    Weigh 280 g coconut oil and 20 g shea butter into the pot. Into a jug, weigh 410 g olive oil, 200 g castor oil, 30 g jojoba oil and 20 g each of sweet almond, apricot kernel and avocado oil.

  3. Make the lye solution

    Weigh 279.7 g distilled water into a heat-safe jug and 137.7 g sodium hydroxide into a dry container. By the open window, sprinkle the lye into the water while you stir, never the water onto the lye, and keep your face out of the vapour. Stir until it runs clear, then leave it to cool, labelled and out of reach.

  4. Melt the coconut oil and shea

    Warm the coconut oil and shea butter on the lowest heat until just melted, take the pot off the heat and pour in the oils from the jug. Let the oils and the lye solution each settle at 30 to 35 °C (86 to 95 °F).

  5. Mix the essential oils

    Weigh 15 g lemon, 10 g lavender and 5 g rosemary essential oil into a small glass and stir them together.

  6. Blend to light trace

    Pour the lye solution into the oils down the shaft of the stick blender and blend in bursts of a few seconds, stirring between them. A fifth castor oil thickens the batter quickly, so check after every burst and stop at light trace, when a drizzle leaves a faint line before it sinks back.

  7. Scent it

    Stir the essential oils in with the spatula, then give two or three short pulses to spread them evenly.

  8. Pour and insulate

    Pour into the mould, tap it on the worktop to bring up air bubbles and smooth the top. Cover it with a board or lid and wrap it in a towel for a day, so the loaf heats through into gel and firms up sooner.

  9. Unmould and cut

    After 24 to 48 hours, when the loaf is firm, unmould it with gloves on and cut bars about 2.5 cm (1 in) thick. Halve them if you want a smaller bar that sits easily in a wet hand.

  10. Cure for six weeks

    Stand the bars on a rack with air all round them for six weeks, or four at the very least, turning them now and then. A young bar feels harsher and melts away faster in the shower.

  11. Wash your hair

    Soak your hair, then rub the bar over it front to back a few times, or lather it between your hands, and massage the lather into your scalp. Rinse for longer than you would a bottled shampoo, since leftover soap is what hard water turns into film.

  12. Follow with an acid rinse

    Stir 1 tablespoon (15 ml) of 5 % vinegar, cider or white, into a mug (250 ml) of water; a quarter teaspoon of citric acid does the same job without the smell. Pour it slowly through your hair and work it in, keeping it away from your eyes, and rinse with plain water afterwards if you like.

  13. Keep the bar dry

    Between washes, stand it on a slotted dish of its own, out of the shower's stream.

Tips

  • Your water decides more than the recipe does. Calcium and magnesium in hard water turn some of the soap into an insoluble, waxy film that leaves hair dull and heavy; that film, and no kind of detox, is usually what the first weeks feel like, and the acid rinse dissolves it. Your water supplier publishes its hardness, and if yours is very hard, a syndet bar will probably suit you better.
  • Sweet almond oil is a tree-nut oil, apricot kernel oil comes from a close relative of the almond, and shea butter is pressed from a nut: name all three on the label and keep this bar from anyone with a nut allergy. To leave out the almond and apricot kernel oils, add their 40 g to the olive oil; the lye stays the same.
  • The two bars differ less than their labels suggest. This one has a little more coconut oil for a brisker wash; the kukui and almond bar has less, with cocoa butter and more shea butter. If one leaves your hair dry or heavy, try the other, but look at your water and the rinse first.

Why make it

A soap shampoo bar for normal to oily hair: castor oil at a fifth of the oils gives a thick, lasting lather, bubbly 37 on our scale, and the coconut oil washes out oil and styling product briskly. People choose soap bars to do without plastic bottles and to keep the ingredient list short. Be honest about your water first. In hard water, calcium and magnesium turn part of any soap into scum (US Geological Survey), and that film is what leaves hair dull and heavy. Soap is also alkaline, and a review of shampoo pH found that alkaline washes raise the negative charge on hair and the friction between its fibres, which is why an acid rinse afterwards helps (Gavazzoni Dias and colleagues, 2014). If your water is very hard, a syndet bar may suit you better.

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 13.8 %
  • Myristic acid 5.3 %
  • Palmitic acid 9.2 %
  • Stearic acid 3.5 %
  • Ricinoleic acid 17.7 %
  • Oleic acid 36.4 %
  • Linoleic acid 7.9 %
  • Other 8.1 %

Saturated : unsaturated 35 : 65

Hardness 32 29–54
Cleansing 19 12–22
Conditioning 63 44–69
Bubbly lather 37 14–46
Creamy lather 30 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.

From the guides

All guides
Intermediate 9 min read

Shampoo bars: what true soap does to hair

Soap shampoo bars, honestly: what alkaline soap and hard water do to hair, why an acid rinse helps, when a syndet bar is the better choice, and a recipe.
Advanced 10 min read

Soap in hard water: scum, chelators and rinse

Why soap turns to scum in hard water, how much soap each litre wastes, what a chelator in the bar can and cannot do, and why coconut soap copes best.

Where these proportions come from

Adapted from the Vegetable Shampoo Bar in Susan Miller Cavitch's The Natural Soap Book, the bar she made for normal to oily hair: her olive, coconut, castor and jojoba oils with small amounts of shea butter and sweet almond, apricot kernel and avocado oils, the castor oil cut from 28 % to 20 % of the oils with most of the difference given to olive oil, without her grapefruit seed extract, at our everyday 5 % superfat and a 33 % lye solution.

Formulation adapted from The Natural Soap Book by Susan Miller Cavitch (Storey Publishing, 1995). The method and notes are ours.

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