Why You Should Always Follow Merino Wool Care Instructions (and How to Do It Right)

Merino wool is an exceptional material – warm, breathable, antibacterial, and self-cleaning. However, to preserve all these natural qualities, it requires gentle care. Here’s what can irreversibly damage merino wool and how to wash it properly.

What Happened in the Photos

Close-up of felted wool surface after improper washing
Detail: the fibers are felted and hardened – a result of temperature shock and excessive spinning.
Damaged merino insert placed on a properly maintained one
Damaged insert (top) vs. properly maintained one (bottom) – visible shrinkage and loss of softness.
Comparison of shape and surface of two merino inserts
Visible deformation and stiffness caused by improper washing and drying.

Merino fibers have a scaly surface. When exposed to temperature changes, mechanical friction, and inappropriate detergents, these scales lock together – the wool becomes felted, stiff, and loses its softness and elasticity.

What Damages Merino the Most

  • Temperature shock – a difference of more than 5–10 °C between washing and rinsing triggers felting.
  • Spinning and wringing – high speed damages and deforms the fibers.
  • Drying on heaters or in a tumble dryer – heat destroys the natural lanolin and fiber structure.
  • Fabric softener – sticks fibers together and reduces absorbency and breathability.
  • Universal detergents, bleach, and enzymes – too aggressive for delicate keratin fibers.
  • Long soaking or strong rubbing – leads to felting.
  • Homemade “cleaning hacks” – such as baking soda, vinegar, alcohol, or citric acid change the pH and damage wool structure.

Kaarsgaren Recommendation: Wash merino by hand using wool detergent. Machine washing is – use Wool  program with very gentle settings.

How to Wash Merino Wool Properly

Option A – Hand Wash (Recommended)

  1. Use lukewarm water 25–30 °C – same temperature for washing and rinsing.
  2. Add a special wool detergent (no softener, neutral pH).
  3. Gently press the fabric, do not rub or wring.
  4. Rinse in water of the same temperature until clean.
  5. Remove excess water by pressing in a towel – do not twist.
  6. Lay flat to dry in a well-ventilated area, away from direct sunlight and heat sources.

Option B – Washing Machine

  • Select Wool program, max temperature 30 °C.
  • No spin.
  • Wash separately, ideally in a wash bag.
  • Use only wool detergent – no softener or homemade cleaners.
  • Do not tumble dry. Shape gently and dry flat.

Quick Care Between Washes

  • Air out regularly – merino is self-cleaning and resists odors.
  • Treat stains locally with lukewarm water and wool detergent.
  • Once dry, gently brush the surface to restore fluffiness.
  • Occasionally use a lanolin treatment to restore fiber protection.

Frequently Asked Questions

Why can’t I use fabric softener or vinegar?

Softener glues fibers together, while vinegar or baking soda alter the natural pH of wool, reducing its softness and elasticity.

Can I wash merino at 40 °C?

Not recommended. Even a 5 °C difference between washing and rinsing water can trigger felting. Stick to 30 °C.

What if the merino is already stiff?

Unfortunately, felted merino cannot be restored. Continue using it gently until it wears out naturally.

The Benefits of Merino Wool – Why It’s Worth It

  • Thermoregulating – keeps you warm in winter and cool in summer.
  • Natural antibacterial properties – resists odor even after prolonged use.
  • Excellent breathability and moisture absorption – keeps skin dry and comfortable.
  • Self-cleaning – often needs only airing instead of washing.
  • Soft and gentle – suitable even for sensitive baby skin.
  • Sustainable and renewable material – obtained by ethical sheep shearing.
  • Long lifespan – with proper care, it stays beautiful for years.

Merino wool is not only a comfortable but also an eco-friendly choice. With the right washing and drying care, your merino inserts or footmuffs will serve for many seasons, staying soft, cozy, and functional.

In summary: Merino wool is a natural wonder – warm, breathable, and nearly self-cleaning. Treat it with care: avoid temperature shocks, fabric softeners, soda, vinegar, or wringing, and it will reward you with years of reliable comfort.