3Gal Better Bottle Ferment on Side

Trying to see how viable this is and toss the idea, maybe gather suggestions, before securing the parts. Have recently found an organic, wildflower honey supplier who is able to provide me with a significant amount for mead making and acquired a refrigerator with digital override for better temperature control.

Issue is there is only about space in the refrigerator for three 5gal carboys, possibly four if I secure them, but tons of empty space which cannot be used; however, were I to use the square, 3gal better bottles I have measured out being able to have nine carboys easily, possible twelve, if laid on the side. This also works better for the recipe since I use a gallon of honey to three and a half gallons of water, letting me produce the full amount as long as I make two batches, which I would be.

Thoughts thus far are to secure the bung into the mouth of the carboy and use basically a blow-off tube. Major concern with this is assuring the end of the tube remains out of the must, so simply orienting the tube at start of fermentation is not enough. One thought is to secure with a clip or some fastener inside the bottle. Simple enough itself other than the way to attach. Thinking food grade caulk? Just a dab on one side, press down, and allow dry. Or looking to fashion a stainless clip which could be attached via screw. Second thought is to use a thick gauge of stainless wire twisted and bent into shape for the opening of the tube for additional rigidity.

The other way would be a little more labor intensive with creating a 90deg arm for an airlock. I have not found any airlock with this or an attachment, but basic design would be a glass pipe heated to create an elbow with a rubber joint to connect airlock and pipe. As long as the airlock is kept above the liquid line, gases will be able to escape without liquid being released I think, but I could be wrong. May combine both ideas and create an elongated glass pipe to reach out of the must and connect an airlock at an angle.

Thoughts, suggestions? Should I settle for just having my three or four 5gal? Should I settle for just having six 3gal upright? Eventually will be making a fermentation chamber from the refrigerator parts, so I may just have ot settle for a while if this gets too complicated.

Or... you could look into large volume food grade containers that will fit in the space provided. You are a new poster here, so look thru the DIY forum. There are NUMEROUS ideas for fermentation vessels. Things from Trash cans (not a suggestion I would follow) all the way up to plastic conical containers originally designed for spraying chemicals but are food safe. You could even get a 15.1 gallon keg and use that. I've also seen 15 gallon cornie kegs that are intended to be used as protable eye wash stations. They have the same exact fittings as a 5 gal cornie. I believe a simple answer would be to find a 15-20 gallon food grade barrel.

Wonderful suggestion which I forgot to explain why I would prefer not to use a larger vessel for the space (was looking towards one of the biggest Speidel Fermenters). Looking first to stagger fermentation; gives me greater consistency. As well, numerous vessels allows me to hold some to further develop over a longer period. Finally is my honing in on recipe by giving me more chance for experimentation.

But will definitely try and find an alternative fermentation vessel which may better suit my needs.

Additional idea which seems easiest is to drill a hole in the side of the bottle and put in a rubber stopper and again use a blow-off tube, then secure a solid bung in the bottle mouth.