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Soap scrap confetti bar

Soap bars cut from a loaf, each two thirds white flecked with multicoloured confetti shreds and one third soft violet, beside a small heap of grated soap on a yellow backdrop

Grated offcuts from earlier batches folded into white batter beside a plain violet stripe, so every bar is flecked with confetti. Soaped cool and chilled so the pieces keep their edges: a good home for bevel trimmings and loaf ends.

Skill
Intermediate
Method
Cold process
Batch
900 g of oils about 1512 g of batter
Hands-on
1 h 15 min
Cure
6 weeks
Gel phase
No keep it cool
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What you need

For 900 g of oils, which fills a 25 × 9 cm loaf mould filled 6.7 cm deep (about 1.5 litres), with one card divider. Weigh everything, liquids included.

Olive Oil · 30.0 % 270 g 9.52 oz
Coconut Oil · 25.0 % 225 g 7.94 oz
Rice Bran Oil · 23.0 % 207 g 7.30 oz
Shea Butter · 20.0 % 180 g 6.35 oz
Castor Oil · 2.0 % 18 g 0.63 oz
Sodium hydroxide (NaOH) · the lye, 100 % pure 124.9 g 4.41 oz
Distilled water · for a 33 % lye solution 253.6 g 8.94 oz
Soap shreds, grated from offcuts · firm cold-process offcuts in several bright colours, grated on the coarse side of a box grater; white portion only 200 g 7.05 oz
Ultramarine violet · 1.5 tsp, violet portion only, dispersed in 15 g of the recipe's rice bran oil 6.3 g 0.22 oz
Titanium dioxide · 1 tsp, white portion only, dispersed in 24 g of the recipe's rice bran oil 4.7 g 0.17 oz
Rubbing alcohol (isopropyl, 91 % or stronger), in a fine spray bottle · misted over the top of the poured loaf against soda ash; it evaporates. Flammable: keep it away from flames 1 tbsp
Frankincense oil · 1.5 % of the oils, at trace 13.5 g 0.48 oz
Rosemary oil · 1.0 % of the oils, at trace 9 g 0.32 oz
Superfat
5 %
Temperatures
Lye solution cooled to room temperature, 21 to 27 °C (70 to 80 °F); oils at 27 to 32 °C (80 to 90 °F)

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Method

  1. Grate the shreds

    Grate 200 g of firm soap offcuts on the coarse side of a box grater, a few colours if you have them, and toss them together. Any cold-process soap works, as long as it is firm enough to grate cleanly.

  2. Line the mould and set the divider

    Line the mould and set it level. Cut a strip of stiff card as long as the inside of the mould and 2 cm taller, wrap it in packing tape, and stand it along the mould 3 cm from one long side, so it splits the mould into a narrow third and a wide two thirds; tape a tab from each end to the rim.

  3. Make the lye solution ahead

    An hour or two before, put on goggles, gloves and long sleeves and, where the air moves, pour the 124.9 g of sodium hydroxide slowly into the 253.6 g of water, never the reverse. Stir until clear and leave it labelled and out of reach to cool to room temperature, 21 to 27 °C (70 to 80 °F).

  4. Disperse the colours

    Weigh the rice bran oil and take 39 g of it. Stir the ultramarine violet into 15 g in one spouted jug and the titanium dioxide into the other 24 g in a second, until a smear on a white plate shows no grains.

  5. Melt and scent the oils

    Melt the coconut oil and shea butter gently, add the olive oil, the castor oil and the rest of the rice bran oil, and let them cool to 27 to 32 °C (80 to 90 °F) while they stay clear. Stir in the frankincense and rosemary oils.

  6. Blend to light trace

    Pour the lye solution in down the blender shaft, tap out trapped air, and blend in short pulses until the batter is smooth and just thickening, thin custard that holds a faint line for a few seconds.

  7. Colour both portions

    Pour 480 g of batter into the violet jug and whisk it evenly violet. Whisk the white into the batter left in the pot, about 780 g.

  8. Fold in the confetti

    Fold the shreds into the white batter with a spatula until every piece is coated. It should be thick enough to hold them where they are and still pour.

  9. Pour both sides at once

    Pour the violet into the narrow side and the confetti batter into the wide side at the same time, a jug in each hand or with a helper, keeping the two levels within about 1 cm of each other so the divider does not lean.

  10. Lift the divider

    Tap the mould firmly on the worktop, untape the tabs and pull the divider straight up and out. Tap again and smooth the top.

  11. Freeze it

    Mist the top lightly with rubbing alcohol, away from any flame, cover the mould, seal it in a large bag or box and put it in the freezer, away from food, for 8 to 12 hours. Kept that cold, the loaf never gels, so the white stays bright and the shreds keep their edges.

  12. Let it come back

    Take it out and leave it at room temperature for a day, until any damp on the surface has dried and the loaf is firm.

  13. Unmould and cut

    Unmould with gloves on and cut bars about 2.5 cm (1 in) thick across the loaf, so every face shows the violet stripe beside the confetti.

  14. Cure

    Stand the bars on edge with air between them, out of direct sun, for 6 weeks, turning them every few days.

Tips

  • The shreds are finished soap, so they go in on top of the recipe: the calculator leaves them out and the lye does not change.
  • Bright shreds show best. Pale or tan offcuts vanish into the white, so save the strongest colours, the bevelled edges and the ends of other loaves, for this bar.
  • Grate soap that has had at least a few days to firm up; very fresh soap smears on the grater instead of shredding.

Why make it

A thrifty bar that turns bevel shavings and loaf ends into confetti, so nothing from earlier batches goes to waste. The base is a mild, palm-free everyday blend, cleansing 17 and conditioning 57 on our scale, and the shreds are finished soap, so the whole bar washes like a good ordinary bar on most skin. Saving soap ends for new bars is an old household habit, never more so than in Britain after soap went on the ration in 1942 (Hansard). Frankincense and rosemary give a warm, resinous scent over whatever the shreds carry. People love it because no two bars look alike. Use offcuts from soaps you know, since every shred ends up on your skin.

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 12.3 %
  • Myristic acid 4.8 %
  • Palmitic acid 11.3 %
  • Stearic acid 10.5 %
  • Ricinoleic acid 1.8 %
  • Oleic acid 42.0 %
  • Linoleic acid 12.7 %
  • Other 5.0 %

Saturated : unsaturated 43 : 57

Hardness 39 29–54
Cleansing 17 12–22
Conditioning 57 44–69
Bubbly lather 19 14–46
Creamy lather 24 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.

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Where these proportions come from

Adapted from Anne-Marie Faiola's almond milk confetti bars: her olive, rice bran, coconut and castor oils with shea butter in place of the palm oil, grated offcuts folded into a white two thirds beside a violet third, and the loaf soaped cool and frozen so it never gels. We use plain water, weigh the shreds, and swap her elemi, which our list lacks, for frankincense, a resin from the same plant family.

Formulation adapted from Pure Soapmaking by Anne-Marie Faiola (Storey Publishing, 2016). The method and notes are ours.

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