Since hydrogen is a light gas and your container has a lid, could you not cut a couple of three inch holes in the top, one to either end and cover then with some nylon or fibreglass screening to vent the gas?
In a pinch, a small blower motor like those used to cool computer boxes could be safely added to exhaust from one opening.
Once you are all set up, do you think the locals will suspect you are making your own alcohol?
David