I asked Aarke why not glass. Answer: With glass, they would have to design the entire bubbler differently because of safety aspects (they would have to surround the bottle during the bubbling process so that it could not burst); therefore plastic. So I ordered the bubbler with a plastic bottle - I'm thrilled. My old bubbler always dripped and had limescale streaks (very hard water here), no problem with the Aarke. And of course it's much nicer.