What is a “Torrefied” Guitar Top?
Players seek out vintage guitars not because they’re old but because they sound great. When I play an old guitar I notice that the notes just seem to pop, that it takes very little effort to get the strings to respond to my pick. Also, I hear the tone as having a certain clarity with a strong fundamental and well-defined overtones. As well- made as new guitars are, and I truly believe that modern guitars are built as well as they were in the past, they just don’t have that “vintage” tone. Until now. About a decade ago, luthiers began experimenting with tops that had been subjected to extreme heat, a process known as torrefaction. I’ve played guitars from a number of builders made with torrefied wood and they all have the dry, woody tone I associate with vintage guitars.
Torrefying, or thermo-treating wood is not a new idea. The concept has been around for centuries, making charcoal is a crude form of torrefaction, but it’s only recently that more sophisticated methods have been developed. The shortest summary of the process is that the wood is heated over an extended period in an oxygen-free kiln (which allows the use of high temperatures without the wood catching on fire). This “cooks off” the oils and resins that normally take many years to diminish as newly harvested wood dries and ages. The theory is that a torrefied soundboard comes close to replicating the cellular structure of the top of an old guitar. Along with sounding more like a vintage guitar, torrefied wood is also more resistant to swelling or shrinking when exposed to climate changes. On guitars given a natural finish, a torrefied spruce top has a somewhat darker color.
What makes the use of torrefied wood on new guitars somewhat confusing is that most guitarmakers have given the process their own term, so here’s a short list of words or phrases that essentially all mean the wood has been subjected to the same thermo-treatment process. Collings calls their torrefied tops “baked,” while Martin calls it “VTS” (which stands for Vintage Tone System). Taylor is using torrefied Sitka spruce tops on their new 600 Series acoustics, calling the spruce “specially aged.” Dana Bourgeois, one of the pioneers in using torrefied wood, calls it “aged tone” and other builders use terms like “roasted” or “acoustic resonance enhancement.”
Some of Gryphon’s current selection of guitars with torrefied tops: