Riser Height for 3" pot still

[Tōtōchtin]

Few nights back I went thru a lot of threads looking for this. Almost all said that there is no column on a pot still. Those that tried to discribe their risers just said they had tall risers and they like that for the lighter flavor. And short risers are better to develope flavors, otherwise riser's height is only important when conidering condensors height.

I just can't help thinking that giving 3 different grain flavors a chance to blend better in a taller riser. I'm looking for info from someone here whose experimented with riser height making whiskeys. I just recieved about 50 triclamps and other toys. I want to make a 2 piece column for my vm part. One of the sections I want to use as my riser for my pot still. Just curious what range in inches/mm is considered the best for making whiskey. I guess if you can document that risers have zero value I'll read that to.

Also do you think a small heating element is needed for a second thumper? I'm not sure how far heat will carry. I figure the heat loss to the first thumpers wash, then it has to heat up the second, might be asking too much.
Toto

[Saltbush Bill]

Gut feeling from my own experience is that without taking things to extremes the riser hight won't make a huge difference.
When I say extremes I mean there may be some difference between a 1 foot riser and a 10 foot riser.
What I can say for fact is that once you get up in diameter, six inch copper for arguments sake.......then riser hight makes a difference.
Probably more so due to a lot more copper surface area and lower vapor speed causing natural reflux than height.
I'm basing this on a run I attempted recently, tried to use my six inch plated column in pot mode, plates all dry.....Deflegmator water turned right off.....no induced reflux at all.
Couldn't even begin to get figures like I would from my 2.5 inch pot still......gave up and went back to the potty in the end.

[NZChris]

You can experiment with this by designing the lyne arm to be able to be adjustable from downhill to uphill using a 90 degree bend where it exits the riser. The longer the better.

[still_stirrin]

… Also, do you think a small heating element is needed for a second thumper?

Adding heat to a 2nd doubler would cause constituents in the thumper with higher boiling points to boil and come out of your product condenser. Chances are that it would result in more smearing and lower proof at the spout. Sure, the product production rate would increase and the liquid accumulation in the 2nd thumper would be less, but what is NOT in the thumper would be coming out of the spout.

When using the boiler alone to add heat, the thumpers force the vapors to bubble through the liquid in them. This causes condensation of the constituents with higher boiling points (less volatile) to condense and this allows refinement of the advancing vapors. Adding heat will disturb this process.

A better approach would be to insulate the vessels and piping to/from the vessels. That way the heat produced in the boiler would be better contained in the still and less heat (energy) lost to the environment. This would improve efficiency as well as performance.
ss

[Dancing4dan]

My pot still riser height was determined by where / what height the product condenser needed to reach.

I use a copper packed riser. The packing traps fusel oils in tails by giving them surface area to condense on. Seems to give a wider hearts cut.

[Salt Must Flow]

Like Dancing4dan said, I make my riser the height I want for ease of collection. My boiler always sits on the floor and I collect on a table or counter top for convenience. I refuse to collect on or near the floor. I use a relatively tall riser because I use a Shotgun condenser (product condenser) installed vertically so like I said, my riser is relatively tall. I insulate my riser because I use the exact same pieces/segments as my 'reflux column'.

I imagine you would find more of a difference in flavor strength if a little reflux was involved.

[jonnys_spirit]

29B878AB-5FF4-4B27-B2E2-FA61AD53A86C.jpeg

One benefit of a taller riser and perhaps a helmet on a strip run is more headroom capacity to prevent puking. I don’t get the feeling that it affects flavor much if at all in this setup - or takeoff abv fir that matter (on a spirit run) but I use it like this anyway

57CC00FC-517D-49D0-AC25-94CD53F8AF81.jpeg

This split top riser on the small alembic is short and squat relatively speaking - I find that I get a significantly higher ABV throughout a run even with no forced reflux. There must be some passive reflux happening. Still no lack of flavor either.

Cheers,
-j

[Tōtōchtin]

You can experiment with this by designing the lyne arm to be able to be adjustable from downhill to uphill using a 90 degree bend where it exits the riser. The longer the better.

By longer were you referring to a long swept elbow or longer lyne arm. I just received 28 2" ferrules and have a bunch of 2" elbows. So I can play. I am assumeing you meant lyne arm on being longer ,the longer the better,makes me ask. While I got you here would you offer the same advice for rum. I was planning on short 2 inch lyne arm for my rum. Using the same pipe when I get a boiler up and running on stream.
I thank you all for your advice.
Tōtō

[Salt Must Flow]

Look how the 'Lyne Arms' are pointed at a downward angle. If the Lyne Arm was pointed at a more upward angle, any passive reflux would flow back down towards the riser instead of running out to the product condenser.

[jonnys_spirit]

lyne-up.jpeg

Compared to something like this ^

Cheers,
j

[NZChris]

viewtopic.php?t=36041

[SaltyStaves]

When I was designing my riser, height was less important to me than interrupting laminar flow.

I see a lot of flat-top boiler lids with large lengths of straight copper tube and to my mind, most of the vapour will travel throughout the still without touching copper until it is restricted in the lyne arm or condensing. Adding a few extra feet of length won't make one bit of difference (other than add delay and require extra energy to get the product out).

[Garouda]

The length of your riser plays an important role because molecules need energy to leave the surface of your wash and make their whole way to the top of the column.
I'm using parts of my Ø3" VM still to have a kind of pot still, no reflux coil, no packing. The length from the lid of my boiler to the top of the 90° elbow is 145cm. In fact, for a real pot still it could be lower, but I have the constraint of my Liebig condenser.
As you can see on the photo, there's a sight glass at the top of the riser. It enables to see all the natural reflux when you are close to the tails, you’ll also notice less output...
That length plus the reduction Ø3" to Ø 1" also causes a kind of VM effect.
To answer your question in a nutshell, the higher your riser, the less, heavier, higher alcohols, fusel alcohols having a higher number of carbon atoms in the chain, can reach your product condenser, except of course if you run your still at full power.

145cm riser.jpg

Also: viewtopic.php?p=7767455#p7767455