Incrementally adding effective plates to an SD potstill

AceNZ

I have an SD potstill, shown in the photo below. I'm also in the process of putting together an SPP LM/VM column.

I'm interested in exploring the still design space in-between these two extremes -- particularly for rum and not-fully-neutral vodka. Short of adding actual bubble tees and plates, what other good ways are there for me to incrementally add more effective plates, or to otherwise improve product quality during spirit runs?

I'm thinking about something like a mini-CM approach, with a variable-length section packed with stainless scrubbers? (I have a Big Baby available to use as an RC/dephleg).

Is it possible to place a single 4-inch bubble plate on the lower end of the torpedo reducer? (and if so, will a copper plate at the bottom of the column have the same anti-sulphur effect as copper foil at the top?)

Are there other configurations / variations worth trying?

grim

I'd argue that with the availability of good dephlegmators (larger, higher surface area), and proportional PID controlled cooling, what were previously considered the negatives of a CM setup (poor reflux control, coarse controllability, inability to operate at 100% reflux), have been eliminated, and the benefits of VM and LM reduced in comparison. Arguable that the added design complexity of VM/LM designs are now negatives in comparison.

10 years ago there were few choices for well built tube in shell dephlegmators. Most of us were winding soft copper tubing into coils and trying to weave horizontal or vertical cooling pipes through the column. Most times back then, we were adjusting the coolant flow with the water spigot valve.

Easy to see why an LM setup would produce better results back then, and why we were looking for alternatives. I'm sure this is considered heresy, but today's CM ain't your pop's CM.

I think both of your approaches will work well. I would have said the challenge with the bubble tray on the bottom of the torpedo is monitoring for a puke, but you have the boiler sight-glass to take care of that.

Only thing I'll add is that a little goes a long way in that "middle ground" - it's very easy to shoot right to the top end of that with only a bit more reflux or a few more inches of packing. Just adding the one plate is going to make a big difference, and the packing the same (even in that small straight section).

AceNZ

@grim thanks for your comments.

I certainly don't have anything against CM -- I'm mainly trying to experiment with different configs and see what works best for what I'm trying to accomplish. I will very likely end up with bubble tees eventually, but it seems like there's lots of (inexpensive) stuff to try between here and there.

Speaking of PID controlled cooling, do you know of a good SD-compatible controller and sensors?

Smaug

That posted configuration is very popular and we have a number of users that have been very satisfied with the flexibilty that it offers.

I don't think you can go wrong.

vooharmy

Lloyd was working on a controller before his retirement, perhaps the work is still continuing in the back ground? Either way there is a really nice post from @CothermanDistilling which details his build for a proportional valve.

AceNZ

@Smaug the setup has worked well for me so far as a potstill -- just trying to figure out some incremental ways to make it a little better.

Smaug

Search "Hawking Rage" on the interwebs

Unsensibel

@vooharmy - I'm playing around with an Arduino but with the spring weather and other time constraints didn't make much headway other than having basic display and temp measurement done. Based on @grim 's eBay links, I have a prop valve and am scouring now for a decent priced interface between the TTL and the 0-10v/4-20mA logic. Once I can move the valve, I'll get the PID implemented

vooharmy

@unsensibel I think the PIDs are a great proven way to move forward. I have an automation box built with PIDs, once I got the values right I was very happy with the results. Currently I'm using solenoids and getting a very respectful 0.5 degree tolerance which suits my needs. The proportional valve produces even tighter results, and eventually I will swap to prop valves.