Technique · Swirl
Drop Swirl in the Mould
The first swirl worth learning. Contrast batter is dropped from a height so it punches down through the base and rises back, and you cut the columns with a single stroke each. Nothing about it is difficult, and no other technique teaches trace control as quickly.
RBase recipe to pour into
| Oil | Share | SAP |
|---|---|---|
| Olive Oil | 45 % | 0.134 |
| Coconut Oil (76 °F) | 25 % | 0.183 |
| Palm Oil | 2 % | 0.141 |
| Castor Oil | 5 % | 0.129 |
| Cocoa Butter | 5 % | 0.137 |
| Oil bill | 1 % | 140.2 |
| NaOH to weigh | 141.6 g | NaOH @ 99 % |
|---|---|---|
| Water to weigh | 330 g | 2.35 : 1 |
| Superfat | 5 % | Lye concentration 29.8 % |
| Yield | 9 × 163.5 g | Cure 5 weeks |
Reference bands follow the usual cold-process targets; the marker turns orange when a figure sits outside its band.
TTechnique notes
Why the drop has to fall
A drop swirl is a density trick, not a stirring trick. Coloured batter poured from 25 cm carries enough momentum to go down through the base rather than spreading across it, and the two batters then equalise and the column rises back toward the surface.
That only happens in a batter thin enough to flow around the falling stream. At medium trace the column lands on top and stops, and you get a blotch. At emulsion the two batters merge into a single colour within a minute. Light trace is the narrow band where the column falls, rises and holds.
Three or four columns, one stroke each
The impulse when you see the columns is to cut them up enthusiastically. Resist it. A drop swirl reads because the columns are still visible as columns — separate, distinct, roughly parallel shapes. Cut each one once lengthwise, then drag one lazy S across the whole loaf to link them, and stop.
Every additional stroke moves colour that has already reached its final position. A drop swirl that has been over-worked does not look more swirled, it looks grey.
The ninety-second wait
Between the last drop and the first chopstick stroke, wait about a minute and a half. In that time the columns finish rising and flatten at the top, and the boundary between the two colours stabilises. Cut too early and you are dragging colour that is still moving; cut after four minutes and the columns have set into a shape you can no longer change.
Add at trace
- 3 g French green clay in 20 g of the water, for the contrast colour
Equipment
- Digital scale to 0.1 g
- Stick blender
- Two jugs and a spoon for dropping the contrast colour
- A chopstick or a thin skewer
When it goes wrong
- The green and the cream blended into a single pale colour
- The batter was at a medium trace when the columns went in, so they never sank and rose, they just spread. Work at a light trace and have the coloured jug ready before you pour the base.
- The swirl is muddy and there are no distinct columns
- Too many drops, or too much chopstick. Three or four columns and one lengthwise stroke each, then one S across the whole loaf. That is the complete list.
- All the columns have risen to the top and sit in a line
- You poured the green from too low, so it never punched down. The height is what does the work: 25 cm, in one steady stream, not a drizzle.
MMix
- Make the base batter and blend only to a light trace — thin enough that a spoon of coloured batter dropped from height will sink and then rise again, which is what makes a drop swirl work.
- Split off 260 g of batter into the second jug and stir in the clay slip until it is an even green. Get this done before the main jug gets any thicker.
- Pour the plain batter into the mould from a height of about 20 cm, so it lands in a thin ribbon and levels itself.
- Now the drop. Hold the spoon 25 cm above the surface and pour the green in one steady stream, letting it punch down through the plain batter. Move the spoon slowly down the length of the mould as the green goes in — you want a column, not a puddle.
- Refill the spoon and drop a second column 4 cm to the side of the first. Then a third. Three or four columns across a 25 cm mould is right; more than five and the swirl turns to mud.
- Wait ninety seconds. The columns need to have risen and flattened somewhat before you cut them.
- Drag the chopstick once, lengthwise, down the middle of each column, and then once across the whole loaf in a lazy S. Stop. Every extra stroke mixes colour that is already in the right place.
- Tap the mould down and insulate for 24 hours.
CCut
- Unmould at 24–36 hours while the loaf is still slightly soft. A fully hard drop-swirl loaf chips at the swirl edges.
- Cut at day 3. Nine bars at about 118 g. Cut from the end, not the middle: the first two bars show the swirl at its widest and the last two at its narrowest, and you want to see that progression before you decide whether the technique worked.
- Do not turn the loaf around when cutting. Keeping the same orientation means every bar shows the same face of the swirl, which matters if you are giving them away as a set.
CCure
- Five weeks. Colour contrast in a drop swirl comes from the geometry of the columns, not from the pigment, so it does not fade or bleed the way a mica swirl can.
- The green deepens for the first two weeks as the last of the water leaves, then holds. Clay is a stable pigment and this bar will look the same at two years.
What matters here
- Light trace. A drop swirl only works in a batter thin enough for a column to fall and rise.
- Drop from 25 cm in a steady stream, not a drizzle. Height is what makes it work.
- Three or four columns on a 25 cm mould. More than five and it turns muddy.
- One lengthwise stroke per column, then one lazy S, then stop.
- Wait about ninety seconds between the last drop and the first stroke.
Questions that come up
- Can I use more than two colours?
- You can, and two contrast colours dropped as alternating columns looks better than one. Three or more starts to look like confetti rather than a swirl.
- Why did my swirl only show on the top two bars?
- Your columns were too shallow. Either the batter was thicker than light trace, or you were pouring from lower than 25 cm. Both have the same effect: the colour never got below the top third of the loaf.
- Does this work in a tall, narrow mould?
- Better than in a wide one, in fact. A narrow mould makes the columns deeper relative to their width, so the swirl is more vertical and reads more strongly on the cut face.
Next on the bench
Cold-process soap is made with sodium hydroxide: goggles, gloves and ventilation, and keep the batch away from children and animals. A swirl is decoration; it does not change the lather, the cure or the mildness of the bar.