One Large Bubble Cap or Multiple? Help.

[Absinthe Pete]

So I'm nearing completion of my large still and now I'm designing the bubble plates. The large professional stills I've seen such as Holstein, use one large bubble cap instead of multiple bubble caps. What's everyone's opinion?

The column is 12 1/2" ID 36" tall with three bubble plates that are 6" apart. This still will be used for making whiskey, absinthe, bourbon, rum and the like. That's why I'm using only three plates to give a little separation. So one big bubble cap or multiple smaller ones. The large bubble cap would make construction easier. Thanks.

[Spirit of Texas Brad]

You just need to allow for enough vapor to pass through the tray so pressure doesn't build up. I put multiple smaller caps just for peace of mind that my one cap would not get plugged and create a pressure build up. It is less expensive for me to build multiple cap trays as well. I'm going to build some single big cap trays very soon and test the differences. My calculations say it should all be the same, but reality is far different from theory quite often.

[porter]

You may run into problems with plates too close. A good 'bubble dance' can span that gap easily. You only want vapor to go to next plate, not liquid.

Also, in practice a single cap will spill vapor to one side if not perfectly level or edge isn't perfect. Try getting bubbles to come out all around a plate under water, won't happen. That's biggest reason for numerous small bubble caps.

[Absinthe Pete]

Thanks for the responses. As for the height I've been able to physically measure other professional stills and that's where I got the number for the distance between plates.

[Beauport Bob]

Porter, I imagine that the reason for the "Teeth" on the edges of our plates? Too spread the vapor?

[coop]

Porter, I imagine that the reason for the "Teeth" on the edges of our plates? Too spread the vapor?

Bob, this is true. The teeth allow for any discrepancies in the column as liquid seeks its own level. Otherwise your vapors would just go from plate to plate up the column without the contact to the copper in each chamber. Coop