Electric guitars came on the scene only in the late 1930s, and then only to those who could afford them. Thus, the acoustic guitar in blues had a long run, and the style continued even after the advent of the more-popular electric guitar. The acoustic guitar remained popular for other types of music (mainly folk and country), but for blues, the electric guitar was the instrument of choice from about 1940 on.
Today, both acoustic and electric guitar blues exist. In fact, there are several sub-genres in each. Acoustic guitar includes
- Bottleneck or slide guitar
- Instrumental blues
- Singer-songwriter blues
Electric blues has two huge offshoots:
- Traditional electric blues, as practiced today by Robert Cray, Buddy Guy, and B.B. King
- Blues rock, which was started in the 1960s by British electric guitarists and continues on through Eric Clapton and John Mayer
Acoustic and electric guitars both produce great blues music, as will virtually any other type of guitar, whether it's an acoustic nylon-string classical or a purple metallic-flake solidbody with green lightning bolts. The blues is unrestricted when it comes to instruments.
Today, acoustic and electric blues each offer a guitarist a world of history, repertoire, styles, instruments, techniques, and heroes to study and emulate. It's no longer a conflict of "go electric or be a front-porch picker," as it may have seemed in the late 1930s. Many players, Eric Clapton being a notable example, are excellent acoustic blues players and have paid tribute in concert and in recordings to their acoustic blues roots.
Though you should always strive for the best guitar you can afford, be aware that blues guitarists — beginning with Robert Johnson — often played cheap instruments like Stellas, Kalamazoos, and Nationals. Hound Dog Taylor performed timeless slide classics on 1960s Japanese solidbody guitars. Sometimes the funkier the guitar, the funkier the blues can be.