Spalted wood, known for its fine black veining, was once a rare and unpredictable forest find. Today, Swiss company Koster AG Holzwelten and research institute Empa produce this distinctive timber through a controlled, scalable process. The result is Myrai — a bio-enhanced wood material that offers architects, interior designers and product designers a sustainable alternative to tropical hardwoods.

From Natural Process To Controlled Innovation

The dark lines in spalted wood come from melanin, a natural pigment produced by a specific sac fungus as it grows inside timber. In the past, foresters left logs in the woods for months, hoping the right fungus would create decorative patterns. However, results varied greatly and quality remained uncertain.

To solve this, Koster AG Holzwelten partnered with Empa in an Innosuisse-funded research project. Together, they developed a precise production method. First, the team adjusts the moisture content of timber boards in a vacuum chamber. Next, they sterilise the wood and carefully introduce the selected fungus. The boards then mature in climate-controlled chambers for several weeks while the fungus creates its characteristic veining.

Once the pattern reaches the desired intensity, the team technically dries the wood, which stops fungal growth completely.

Importantly, this specific fungus does not weaken the wood’s structure. Instead, the timber retains strong flexural performance, making it suitable for functional and decorative applications alike.

High-Value Applications In Architecture And Design

Because the veining forms within the wood itself, the pattern runs through the entire material rather than sitting on the surface. As a result, each board remains unique while still meeting commercial quality standards.

Designers can use spalted wood in furniture, interior wall cladding, bespoke flooring, cabinetry, musical instruments and smaller design objects. Moreover, its marble-like aesthetic creates a strong visual identity without synthetic coatings or printed finishes.

For interior architects in particular, the material offers a natural yet high-tech surface that connects craft, biotechnology and contemporary design.

Upgrading Underused Local Hardwoods

Equally important is the sourcing strategy. The company works with native hardwood species such as maple, beech, ash, lime and poplar. These woods often end up as firewood because the market considers them visually less attractive.

By transforming locally grown timber into a premium design material, Myrai increases the value of regional forestry resources. Consequently, it reduces pressure on tropical imports and supports shorter supply chains. Furthermore, when designers use wood in long-life applications rather than for energy, the material continues to store carbon.

Biofabrication With Circular Potential

The development of Myrai shows how biotechnology can enhance natural materials instead of replacing them. Rather than applying chemical treatments or artificial finishes, the process works with biological systems to create added value.

As bio-based innovation moves from laboratory research into commercial production, materials like controlled spalted wood demonstrate how sustainable design can combine aesthetics, performance and local sourcing in one coherent solution.

Source & photos: Empa