Lower ABV output on pot still with sight glass?

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andrew_987789
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Lower ABV output on pot still with sight glass?

Post by andrew_987789 »

Hi all,

I've had my alembic pot still for a while as stock. On my last few runs I was, from memory, getting about 70% ABV at the beginning of the run, which declined over time, of course.

I've recently added a sight glass and copper scrubbers to the setup, and run a few stripping runs. All fine, but didn't measure ABV.

I ran my first spirit run last night with the glass, and after measuring ABV found the initial output was closer to 50%.

Not sure why the drop.

A few changes between the 70 and 50 run.

70% runs
Was using a 2000w, 25L boiler.
The last few runs were TPW wash or blackstrap rum.

50% run
Sight glass + Scrubbers
Was using a 2400w, 35L boiler
Rye mash

A few thoughts on contributing factors.

Lower output from the Rye, compared to the basically pure sure TPW and molasses?

I was using a more powerful boiler, but it had only the 1900w element on and was powered down as well, the same as I did before - Maybe it's more efficient though and I'm underestimating the output compared to my last one? It's running hotter than I think, and blasting out more water?

Other people's thoughts?

If anything I'd have thought the sight glass might increase ABV a fraction, what with the scrubbers providing a tiny amount of reflux.

Not sure where the 20% drop has come from.

Cheers all.
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Stonecutter
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Re: Lower ABV output on pot still with sight glass?

Post by Stonecutter »

The sight glass and scrubbers aren’t going to do anything by themselves. You’re going to need some sort of reflux “device” to bump up your ABV. To be clear on things, when were you Measuring abv? During the run? Or after? And how were you measuring, were you Using a parrot? Will need more info regarding your rye mash to determine more from that. You used a bigger element and a bigger boiler you may have pushed to hard and smeared, resulting in a lower abv. But who knows. A little bit more info would be helpful.
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Dancing4dan
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Re: Lower ABV output on pot still with sight glass?

Post by Dancing4dan »

Would be best to post a pic of your set up
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Re: Lower ABV output on pot still with sight glass?

Post by Stonecutter »

How are you controlling your power input? Did you water down your stripping run at all?
Edit: posted same time as Dan
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Re: Lower ABV output on pot still with sight glass?

Post by NZChris »

Compare the ABVs of the washes.
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Re: Lower ABV output on pot still with sight glass?

Post by jonnys_spirit »

Post some pics of your alembic still please. You mention both a 25l and 35l boiler which sounds like two different stills to me. How did you attach a sight glass and mesh to an alembic?

I have a small batch alembic that I get close to 90% out of (upper 80’s) when I run it then it drops off pretty sharply.

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Re: Lower ABV output on pot still with sight glass?

Post by andrew_987789 »

Stonecutter wrote: Mon Jun 27, 2022 4:05 pm To be clear on things, when were you Measuring abv? During the run? Or after? And how were you measuring, were you Using a parrot?
The 70% and 50% is measuring the first jar, the day after the run. Measured with a standard alcometre.

Same 100ml of foreshots discarded from all runs.

Stonecutter wrote: Mon Jun 27, 2022 4:05 pm You used a bigger element and a bigger boiler you may have pushed to hard and smeared, resulting in a lower abv. But who knows. A little bit more info would be helpful.
Possibly. Will do the next run at lower power and see what that brings.
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Re: Lower ABV output on pot still with sight glass?

Post by StillerBoy »

andrew_987789 wrote: Mon Jun 27, 2022 3:29 pm 70% runs
Was using a 2000w, 25L boiler.
The last few runs were TPW wash or blackstrap rum.

50% run
Sight glass + Scrubbers
Was using a 2400w, 35L boiler
Rye mash
You can't compare unless the ABV of each wash is provided, as that's the determining factor..

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andrew_987789
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Re: Lower ABV output on pot still with sight glass?

Post by andrew_987789 »

Stonecutter wrote: Mon Jun 27, 2022 4:07 pm How are you controlling your power input? Did you water down your stripping run at all?
A power controller, yes.

I did actually water it down a bit. Added roughly 3L of water to the boiler with the 25L of wash. Just to reduce the viscosity a bit from the Rye.

This is something I didn't do on the previous runs. Definitely no more than 3L added though.
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Re: Lower ABV output on pot still with sight glass?

Post by andrew_987789 »

jonnys_spirit wrote: Mon Jun 27, 2022 4:40 pm Post some pics of your alembic still please. You mention both a 25l and 35l boiler which sounds like two different stills to me. How did you attach a sight glass and mesh to an alembic?
Not different stills.

I previously had a 25L boiler, I now have a 35L boiler.

Everything from the dome up is the same, just more volume and heat below.

I can post back with a pic, but the attachment order was 'Copper dome > sight glass stuff with scrubbers > condenser'. Nothing out of the ordinary.
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Re: Lower ABV output on pot still with sight glass?

Post by andrew_987789 »

StillerBoy wrote: Mon Jun 27, 2022 5:04 pm You can't compare unless the ABV of each wash is provided, as that's the determining factor..
I don't have any of the earlier runs wash ABV recorded, unfortunately. Something for next time.
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Re: Lower ABV output on pot still with sight glass?

Post by Stonecutter »

Yeah man, it looks like the small alterations in your protocol ended up giving you different results. As mentioned above, different ABV going in the pot is going to change what comes out. I wouldn’t have worried about the “mouthfeel” of the rye but experimenting makes the hobby fun. Some good advice has been given. Take as many notes as you can and hopefully some of the why’s should become more apparent.
Good luck :thumbup:
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Re: Lower ABV output on pot still with sight glass?

Post by Stonecutter »

I’ve done some snooping and it looks like you’ve been fiddling around with your sight glass for a bit. That sight glass is really nothing more than to help see if you’re flooding, I’m not sure what spurred you to use it without reflux other than to add some more copper in the system. Have you made a run using reflux? I’ve never looked into the t500 and I’m not sure how the reflux works on them. During my 34-40% Spirit runs using a short CM jacket on a 2” column with one small copper packing inside and minimal reflux I pull 85% pretty easily for most of the run.
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Re: Lower ABV output on pot still with sight glass?

Post by andrew_987789 »

Stonecutter wrote: Mon Jun 27, 2022 6:42 pm I’ve done some snooping and it looks like you’ve been fiddling around with your sight glass for a bit. That sight glass is really nothing more than to help see if you’re flooding, I’m not sure what spurred you to use it without reflux other than to add some more copper in the system.
Yep, understood.

I have been doing some fiddling around for fun, that said, the primary reason for buying the sight glass was visibility when doing black strap molasses runs, because that stuff is a BIIIIIIITCH for suddenly puking.

As well as adding some copper in the vapor path, as you said.

I'm not expecting the sight glass to do wild and wonderful things, or convert one type of still into another. I was just surprised a bit surprised to see such a difference in that first jar's ABV from one run to the next.

Just asking/triple checking in case I've missed something :lolno:

Difficult to pinpoint a cause when you've changed a number of things from one process to the next though, I realize.
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Re: Lower ABV output on pot still with sight glass?

Post by Stonecutter »

I hear you loud and clear man. As we venture down the rabbit hole eh?
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Re: Lower ABV output on pot still with sight glass?

Post by NormandieStill »

I would have thought the abv going in was the most obvious candidate. Most sugar wash recipes seem to produce around 10% abv whereas I wouldn't expect to get much above 7% for an AG mash. That's obviously going to effect your abv coming out on a pot still.
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Re: Lower ABV output on pot still with sight glass?

Post by StillerBoy »

NormandieStill wrote: Mon Jun 27, 2022 9:00 pm I would have thought the abv going in was the most obvious candidate. Most sugar wash recipes seem to produce around 10% abv whereas I wouldn't expect to get much above 7% for an AG mash. That's obviously going to effect your abv coming out on a pot still.
He got lots to learn yet, but haven't learn the basic yet of why the boiler load abv and volume determine the alcohol content and behavior is important in a spirit pot run.. hopefully he's learn somethings with this experience..

The good thing was that he's mindful there was a difference.. there's hope..

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Re: Lower ABV output on pot still with sight glass?

Post by EricTheRed »

my personal experience - the more power you put in, the lower the ABV
So you have gone from 1900W to 2400W, the abv will be lower as you are pulling more water along
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Re: Lower ABV output on pot still with sight glass?

Post by Twisted Brick »

On a pot still spirit run, the difference in boiler-charge volumes doesn't change the boiling temp (Raoult's Law) of identical still charges, regardless of the power applied. Like others have alluded to, the large disparity in the OP's two initial takeoff ABV's should have pointed directly to the difference in starting ABV's as the culprit.
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Re: Lower ABV output on pot still with sight glass?

Post by StillerBoy »

Twisted Brick wrote: Tue Jun 28, 2022 8:26 am On a pot still spirit run, the difference in boiler-charge volumes doesn't change the boiling temp (Raoult's Law) of identical still charges, regardless of the power applied.
Very important point stated there TB..

It should be one of the first things a beginner be requires to learn, but most never learn to monitor their low wine ABV levels prior to the spirit run..

When I read threads like this one, it me wonder how they are able to determine where they're at during the run..

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