Though it's an ever changing target, I've recently taken to using the word "jazz" more and more when I address the recurring question of genre that folks put to us: "so what kind of music to you play?" Folks ask this even when they've been listening to us play for several songs or more. It's a deceptively complex question.
I'm being a bit mischievous, though, when I use the word "jazz" in conjunction with genre, because, following Bill Evans and others (see the video below), I've come to understand the concept of jazz foremost as a process -- an approach to music that relies on informed improvisation. Perhaps a more common way of understanding "jazz" is to think of it as a "style" of music, though, which people variously hear in their mind's ear as bebop or smooth jazz or what-have-you. Obviously, that's not what I'm talking about when I talk about Twang as jazz, with the notable exception of a few pieces which rather obviously invoke elements of the "jazz style" (to the extent that such a thing even exists).
But Bill Evans can explain all this far better than I, unsurprisingly. So I humbly offer you a bit of musical documentary, Bill Evans on the Creative Process and Self-teaching, recently discovered on a wonderful website called Open Culture.
This is an inspriring film about music and the work that goes into it. Evans elucidates musical and creative concepts that very much resonate and help shape my own thoughts on these matters. In particular, his approach to the tension between frameworks and improvisation is fascinating and useful. In keeping with this way of understanding things, our own best pieces are the ones that provide rich base structures for improvisation, leading us to songs that are recognizable from performance to performance as "This or That," and yet still loose enough for us to surf the musical moments that arise. To my understanding, that's a kind of jazz, even when we're using the vocabulary of roots rock.
Most importantly, this "jazz" approach gives us room to grow. And when I listen to Evans play anything on the piano, I know it's an endless road we're travelling. Luckily, I think that's probably the best kind.