New VM build, first ethanol cleaning run

[MartinCash]

Hi guys,

Firstly I'd like to say that over the last couple of years, and despite the lack of posts, I've spent what seems like a million hours reading up stuff on this website, and I think it's an absolutely amazing resource. I built and have been successfully using a pot still for flavoured spirits (mostly rum using HookLine's recipe - THANKS!), and recently finished building a VM still.

I'd originally wanted to go with a Boka-type column, but decided to build a VM for ease of build and running. I left enough space for slanted plates below the condenser so I can add them afterwards if I choose to. The packing length of the column is 1.2 m of 2-inch copper, but if I pack the structured copper right up to the vapour intake, it's about 1.4 m. The head is attached using 2-inch threads, so I can extend the column vertically if I wish. My ceiling in the shed is 5m up, so the only issue with height is stability. The vapour intake is 2in, reducing to 3/4in for the gated valve, then to 1/2in for the elbow and liebig (1/2in inside 3/4in). I'll post some pictures on the weekend if I'm home. I attached it to the keg boiler using a 2-inch ferrule TIG-welded to a 50mm straight joiner and PTFE gasket. It feels rock-solid.

Anyway, I finished the build last weekend, gave her a good clean, did a vinegar run followed by a plain water run, checking for leaks, and last night did a short ethanol run, using old feints from the pot still, since I was unlikely to use them for anything else. I ran the still with no packing, as this was a cleaning run. The flow-rate was approximately 1.8L per hour with the gate-valve fully open, but I expect this will reduce when I add all the packing? Alcohol was 90% with no packing and running with gate fully open at full blast.

I am optimistic that, once packed properly, with the right water flow, and judicious use of the valve, I should get some good neutral. I won't have time to test it for a couple of weeks. I have to say, I found the VM design very easy to build, and would recommend it to anyone. If you use interchangeable heads, you can attach a boka head if you like, or build a combo, as I plan to eventually.

The only thing that makes me nervous is having the product outlet above the boiler. I use propane with the pot still, but potentially having azeotrope dripping onto the boiler and propane flame is not confidence-inspiring. I've made a parrot's beak that takes the product a little off to the side on a bench, but what methods are people with propane-fired stills using for safety? I could put a 1/4in collection tube to take the product far away from the still... but the risk of knocking something over onto a flame is still high. My shed is huge, and I can run in the middle of the concrete floor away from anything else flammable, but still... I think electric is going to be the only way to go long term.