Violins are like fine wines: They can get better with age. Decades of humidity stiffen the instrument’s wood—usually spruce—making tones resonate longer. Years of playing also weaken the wood fibers, which is a good thing. Called creep, the phenomenon makes wooden bookshelves sag, but enriches the violin’s overtone spectrum. And as the wood decomposes with time, a violin will lose its density—and sound better. But you don’t have to wait 300 years for your violin to get that mellow, aged timbre. Dr. Francis Schwarze of Swiss Federal Laboratories for Materials Science and Technology has discovered how to speed up the aging process: fungus.

Scientists have long known that trees with fungal infections have softer wood. But Schwarze realized that not all fungi cause total rot. Rather than destroy a tree’s cell walls, some fungal infections just thin them out. Two species in particular—Physisporinus vitreus and Xylaria longipes—cause wood density to drop while improving its acoustic properties. So Schwarze hired two luthiers to make a violin from fungus-infected wood, and, in 2009, a finished instrument was tested against a 1711 Stradivarius. The result? A jury of experts thought the new violin—which had been covered with fungi for nine months—was the multimillion-dollar instrument.