jbarchuk:
How about get a cheap 'touch lamp.' Open it up and find out how they did it. They usually have metal base. Inside is doubtless a dielectric and another metal plate and a little circuit. You can recreate it or even easier pull the guts out and adapt it to your jar.
The "touch lamps" operate by sensing capacitance against the mains - 110 or 240V. The "ground" side of the detector is actually the full mains voltage so that the capacitance of a person touching it provides a capacitive coupling to the actual ground. I do not think he wishes to connect his bottle to the mains. 