Use this design alot on survival so compacted it a little bit for my 100 subs on youtube :D

How it works:
You click the button and 3 water bottle's will get disposed in the brewing stand (and redstone signal goes to selector panel for ingredients) once the light is off the machine is done the potions will end up in the chest and you can click it again.

Click Here for the tutorial world download/schematic are downloadable in description.




Version with TangoTek's selector design