Why Some Soaps Cause Dye Bleeding in Hand-Dyed Wool – And What You Can Do

Recently, a customer reached out after her hand-dyed merino leggings started bleeding dye during a wash. Given our meticulous dye process—where we fully exhaust the dye and ensure clear rinses multiple times before they even leave our studio—this was surprising. What was causing this?

With similar leggings for my own daughter that never showed any dye issues, I was stumped. Then, it hit me: could it be the soap? Inspired to solve the mystery, I set out to test how different soaps interacted with this fabric. Here’s what I found.

The Tests

1. Baseline – Warm-Hot Water (No Soap)
Starting with just plain warm-hot water (about as hot as you can handle without discomfort), I gently agitated the leggings. With no soap involved, there was absolutely no dye bleed. This reinforced that the dye is indeed exhausted during our dye process and should stay in place.

2. Eucalan Unscented – The Gentle Wool Wash
Eucalan is a go-to for delicate washes, great at handling general dirt without stripping away color. After agitating in warm-hot water, I saw zero signs of dye bleeding—exactly what I expected. Eucalan’s mild formulation makes it a safe choice for hand-dyed items when you’re looking for a gentle clean.

  

3. Soak Wash Unscented – A Slight Leak?
Next up was Soak Wash, which is slightly stronger than Eucalan and has a mild clarifying effect. After some agitation, the water was a little murky, likely from the soap itself, but any dye leakage was almost imperceptible. Soak is a favorite of mine for everyday wool care and especially handy when faced with gum or other stubborn residues.

  

4. Unicorn Fibre Wash – Stain Slayer, But Dye Mover
Finally, I tried Unicorn Fibre Wash—the same soap the customer had used. Right away, I noticed visible dye bleed as the soap was agitated. Once I rinsed the leggings thoroughly, though, the water ran clear again, and there was no further dye release in plain water. It seems that whatever makes Unicorn so effective at lifting stains might also disturb the dye in hand-dyed fabrics.

  

See the unedited video below:

Conclusions and Recommendations

Based on these tests, here’s a quick guide for choosing the right soap for your hand-dyed merino wool:

- Eucalan: A gentle, reliable choice for hand-dyed fabrics and general washing needs.
- Soak: Ideal for everyday washes; it’s mild enough for most wool but do a patch test on hand-dyed items.
- Unicorn: Excellent for tough stains and pit deodorant marks, but it may cause dye bleed on hand-dyed items.

For adventurous spirits who love their hand-dyed woolies, these soap tips should help keep colors vibrant and fabric soft, wash after wash. Got questions about washing or caring for your wool? Drop a comment!