Pot stilling with a detuned LM reflux still

[AussieCol]

Can anyone advise if a detuned (scrubbers removed) LM reflux column (1 meter high and 400mm diameter) will enable me to pot sill a reasonable all-grain whisky? Can it also be used for stripping runs or do I really need a pot still as well? Cheers, AussieCol

[johnhopper1957]

You can use a detuned reflux still for flavoured spirits by removing most of the packing, you can also strip with it. Distillate will come off pretty warm. A post still is the best option for flavoured spirits and reflux for neutral spirits. Some people don't want to make or buy 2 stills though.

[F6Hawk]

Why detune at all? Run a fast reflux and you will get flavor, but higher ABV. I have run mine in pot still mode, and I get flavor. I have run in reflux, and I get nearly as much flavor, less heads and tails, and over 80% ABV. So many options...

[myles]

There are two main problems with running any sort of reflux column in pot still mode - dependent on the column design.

1. The product condenser should not be big enough. It should have been designed for the power levels to be expected on a normal spirit run and you are now proposing using more power.
2. The atmospheric vent on the reflux condenser. This is a potential pathway for vapour to atmosphere if you turn off the reflux condenser cooling.

You don't need to do anything with the packing, once it has heated up it ceases to function.

A reasonable compromise is to put a connector between the reflux condenser and the top of the column. In pot still mode remove the entire reflux condenser chamber and substitute a simple bend leading to a bigger condenser.

Alternatively add in a short connection to route the atmospheric vent into the vapour path just before the product condenser, and add in a second stage condenser. (The reflux condenser will function normally in reflux mode, if its path to atmosphere is via your product condenser.)

[F6Hawk]

1) How does a reflux use more power? When I run in reflux mode, my burner is turned down lower than when I run in pit mode. My output is less (slower) than in pot mode.

2) I don't turnoff the condenser in pot mode. I make sure my power is low enough that I don't have vapor escaping. But if you are worried about that, just cap the vent when pot stilling.

Or am I missing something here? I certainly don't have your experience in 'stilling, so perhaps I am thinking wrong here.

Thanks Myles!

[myles]

No problem. Most folks do both a stripping run or a pot still run, at a far higher power level than they would use for a reflux run. Consequently, they will need more thermal capacity in their condenser than it was designed for.

The fastest way to do a strip run (and most folks want speed in that application) is to turn OFF the reflux condenser. If you are still refluxing then you have reduced your potential output speed.

Using reflux for heads compression is a good idea, if you intend to make a cut on your strip run. That it is a good method and it is one that I would recommend. However, after that cut the ideal would be to turn off the reflux condenser and increase your power input.

If you just cap the reflux condenser and turn the power right up there is a possibility that you will have vapour exiting your product condenser. What you do sounds fine, and you are running your still in pot mode within the capability of your reflux condenser. That is very sensible. However, you are not utilising the full potential of your BOILER.

If you had more condenser capacity available, your strip run could be carried out at a higher power level. You would be able to utilise more of the potential of your boiler. This really applies to strip runs only.
On a normal pot still spirit run, most folks do NOT run at full boiler power. You could find that even with a dedicated pot still head on your boiler, you might not do your pot still run any faster than you do now.

[F6Hawk]

I got you. And I think I see the problem with my reply... I am running a Boka, not LM. So turning off condenser is not a good idea, I think. But your explanation opened my eyes to a couple of things. So as always, I am learning from all my reading here.

I recently added a short liebig to my Boka, so I get cooler product when running in pot mode.

Thanks again for the input, Myles!

[AussieCol]

Thanks for all the replies. Sadly the explanations went way over this "newbie's" understanding of stills and methods. I am fortunate enough to have a pot still and reflux still but, as they use a common boiler and lid, this involves dismantling and reassembly depending on whether I'm doing neutrals for the other half's Gin, Pernod, etc, or my attempts at a good Scotch malt whisky. I was hoping to come to a reasonable compromise with just one still set-up - just lazy I guess. I think I'll live with the assembly issues and make the best I can with the correct "tools". Thanks again for your input. AussieCol

[myles]

AussieCol,
I am trying to get round this issue by putting the column over a thumper. Just something for you to think about.


I will be using a valve to direct the boiler into the thumper/column or a strip condenser. Always 1 path open.

[AussieCol]

Thanks Myles, and here I was thinking Thumper was a rabbit!! But seriously, my stills are very simple and very basic compared to your wonderful "beasts". I'll take the opportunity to learn as much as I can from operating them and then decide whether I need to upgrade at a later date. The pot still is an all-stainless shop bought CM unit and the LM column is a simple and effective all-copper unit with a cold finger at the top and a single plate in the column. I think I fall into the category of interested pensioner hobbyist working towards low-cost, low volume, quality alcohol (not a big drinker, but love to sip a nice Glendronach single malt) rather than someone who wants quality and a greater quantity - hence the 25 ltr electric boiler I'm using. I'll post some pictures of the stills over the next day or two, to give you an idea of what I'm working with. If there are low-cost improvements I can make, then any reasonable suggestions would be welcome. Does insulation on your reflux column make much difference - mine isn't insulated? Cheers, AussieCol
p.s. Really not sure what a thumper is or what it does. :0)

[AussieCol]

Hi Myles, here are a couple of shots of my basic setup. The first shows the copper LM, the second shows the stainless CM pot head hanging on the wall (screws into the same boiler lid) and the third shows my collection method via a needle valve into a copper parrot. Is there anything to be gained by insulating the copper column?
The stainless CM pot is not ideal because of shortcomings in column diameter and lyne arm length, but it was cheap, and does produce reasonably good stuff, albeit at a slow rate with lots of fiddly adjustments to water flow. I have plenty of time but limited funds means I can't splash out on new equipment, so any suggestions for low-cost improvements, if needed, would be appreciated. Cheers, AussieCol.

[Ayay]

Further to the previous great answers, pot stilling works best if you can do a few strip runs first. A reflux column generally has neither the power nor the condensing capacity to do a strip run.

You can do a single run (plain wash without stripping) in pot mode using your Boka as is by simply keeping the needle valve wide open for the whole run. This will prevent forced reflux but there will be some passive reflux. Running a column in this manner means you control the output by only adjusting the heat input. When the first drip appears out the delivery tube, turn the heat down to maintain 1 drip/sec to get the heads out, then increase the heat to 2-3 drips/sec for the hearts, and tails can be stripped as fast as your still can go. Determining when the heads are ending and the hearts beginning is tricky, so collect in small containers in order to make the cuts later. Running this slow in pot mode is well within the capability of a Boka, and the resulting ABV will be much higher due to the passive reflux. Try it as slow as above, then experiment going faster.

[myles]

On the column insulation issue - there are a lot of folks that do not insulate, and manage quite well. I suspect a lot is down to your ambient conditions. Strong cold draughts can be a bit of an issue for an uninsulated column, but if your still is located somewhere reasonable stable in terms of temperature you should be OK.

In most cases I would try it without insulation first. If you then have column temperature stability trouble, try insulating to see if it makes things better.

[AussieCol]

Thanks Ayay, appreciate the reply. So, are you saying that I don't need to remove the packing in the column to run the Boka as you describe? Otherwise all is clear and I'm looking forward to my first run when the all-grain wash is finished. Cheers, AussieCol