New VM build, first ethanol cleaning run
Posted: Thu May 02, 2013 8:20 pm
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.
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.