Rachel Rosenkrantz is the Providence, Rhode Island-based luthier who makes – and grows – the Mycocaster. It's the latest in a line of instruments she has built with non-standard, more sustainable materials, like eggshells and fish skins. The name is a nod to the world famous Fender Telecaster and Stratocaster guitars, was suggested by a colleague at Rhode Island School of Design (RISD), where Rosenkrantz teaches Spatial Design. This is the first of her guitars where the name came first. 

"For anything with 'caster' in the name, there is an immediate, iconic kind of shape that comes to mind," says Rosenkrantz. "This is my own design with my own proportions, but with a kind of wink to a classic." 

Rosenkrantz used digital design software to shape the body. The team at Ecovative used those designs to produce a mold, which she then filled with MycoComposite material. After several days of growth, the body was dried in the oven, the lines from the drying racks lending a subtle aesthetic touch. The rest of the guitar was built around the mycelium core. The neck attaches directly into a slot made in the mold, while the bridge plugs directly into the mycelium. The shell of the guitar is outlined by a ribbon of rosewood, and folds around the body like a jacket (or a taco shell, according to Rosenkrantz), guarding it from dings and aggressive picking.

"It needs protection, because its texture is almost like the crust of a cheese, or a bread crust," says Rosenkrantz. While wood guitars are typically sealed in lacquer, this would compromise the acoustics of the mycelium material, as well as its unique appearance. "It has this kind of agricultural brutalist thing, there's something very honest about what it is, and I like that."

Mycelium, it turns out, has amazing acoustic properties. Its ability to diffuse sound makes for effective sound-absorbing tiles, but it works the other way, too. "If the sound is away from the mycelium, it absorbs it, but if the source of the sound is emitted from the core of it, it diffuses it," says Rosenkrantz. "Not as loud as an acoustic guitar, but if you wanted to make an electric guitar out of it, acoustically, unplugged, it still has resonance." To demonstrate this, Rosenkrantz pulls a Bluetooth device from her bag, a portable audio driver that effectively turns any flat surface into a speaker. Placing it on the Mycocaster body, she chooses Django Reinhardt from her phone, and presses play. Suddenly, the room fills with sound, the mycelium acting as a speaker.


Rosenkrantz has already grown 12 Mycocaster bodies, including one that she deliberately allowed to sprout mushrooms. It now sits in a frame ready to be hung on her workshop wall. Her hope is to get an ensemble of four mycelium instruments together for a concert. Part of the reason for a mycelium guitar – besides being just plain cool and interesting – is the scarcity of 'tonal' woods typically used to make instruments. Guitars, as most people know, are usually made from wood. While wood is an amazing material for acoustic resonance, aesthetic beauty and long-term durability, species like ash, alder, maple, Brazilian rosewood, walnut, ebony, and others are at risk of overharvesting. That's part of what led Rosenkrantz to seek more sustainable alternatives to traditional instrument materials. The fingerboard of the Mycocaster, for example, is made of Richlite, which has the look, sound, feel, and strength of ebony, but is actually made from paper glued together with eco resin and compressed under high pressure. 





Guitars are some of the most recognizable objects in the world. Take a silhouette of the tuning pegs, or part of the body, and most people will still instantly understand what it is. Guitars dominated popular music for decades, and are still prominent in culture despite the rise of less string-dependent electronic or dance music. But over that time, the guitar hasn't changed a whole lot. The body styles of the 1950s are still popular today, and despite a few new materials and paint colors and other tweaks, guitars are essentially the same as they've always been: Pieces of wood glued together, covered in lacquer and maybe paint, with some strings stretched across its length. 

The Mycocaster signals another way to think of how guitars — and instruments in general — are made and maintained. Rather than build an instrument that is made of scarce materials and meant to last practically forever, to grow a guitar means that it can be renewed over time. If a new design feature comes out, or if the guitar is damaged, replacing it is a simple matter of growing a new one. This also means that the costs could be much lower for high quality instruments. 

When Rosenkrantz does use wood, it is according to the Convention on International Trade in Endangered Species of Wild Fauna and Flora, or CITES, an international trade agreement that provides guidelines for the sustainable use of plants and animals. But another of her goals is to make an instrument completely free of wood. Doing this would usually involve plastics or other synthetic materials that come with their own environmental problems. To sustainably produce instruments at any scale will require experiments with new materials that come from and return to nature, mycelium among them. It also means changing how we think of instruments and their lifespans. 

"I like the idea that you can grow the body of your guitar in a very short time," she says. "Let's say it degrades in five years – people can just grow another body and keep the neck. Or let's say there's an improvement or another look to it in three years – it can be swapped. That's my goal. And maybe over time we can make them better sounding, or better in other ways. Maybe it's just not forever."

Order Grow It Yourself™ mycelium material and grow your own guitar!