Yes it is! On his site there is a picture that shows the bottom of the unit, and there is a hole that allows you to adjust the glass chamber. I believe it comes with a plug as well.That's cool. Do you happen to know if the VHB 3D 3S (portable version) chamber is equally adjustable?
I just tried adjusting the tempest air slits to half-closed and ran it through water: aaaand there is the flavor through water!
For the extreme flavor chasers, try playing with the air slits!