Head space in a still

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Tx Mike
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Head space in a still

Post by Tx Mike »

I've got aQ i cant find a direct answer for, I've got a 20g pot i use for my pot still, i ran a 5g mash through it and had a hard time with cuts, my question, is the 15g of head space too much area to have a clean cuts? It has a flat lid with a 1¼ copper male for the vapors to escape to the condenser. I feel like more mash volume would rectify this. Can i simply add 10 extra gallons of water to fill the empty space? Seems like a simple fix. 15 gallons of straight mash is much more end product than i need/ want.

Thanks in advance
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Re: Head space in a still

Post by Setsumi »

the headspace is not the problem. it is the small ammount of alchohol that is the trouble. use a larger volume of charge or strip 2 or 3 charges to increase the volume to help with cuts.
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Re: Head space in a still

Post by still_stirrin »

+1 to what Setsumi said.

It’s not a matter of the ullage that makes cuts difficult to determine, it’s the amount of wash and the “pace” of the boil, ie - rate of vapor production.

For example, if you ran your 5 gallon wash in a 6 gallon boiler and you collected at the same rate (liter per hour), you’d get the same amount of smearing of the fractions through the run.

And thinking about it, when your 20 gallon potstill is producing vapor, the ullage (“headspace” as you called it) will be filled with vapors as they make their way to the riser. Separation of fractions does not occur in this chamber because the vapor constituents are mixing continuously in the vapor state. Separation can only occur when the lower volatile constituents condense from the vapor while the higher volatile constituents progress towards the product condenser “on the other side”.

Small distillation runs are difficult to make cuts on, especially if you aren’t experienced at it. A full boiler will not only give you more product, it will be easier to make your collection better. Time to get the fermenters working!
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Re: Head space in a still

Post by IMALOSERSCUMBAG »

The alcohol in your mash is what it is. Adding water doesn't change the amount, just the %. If you have 1 gallon of alcohol in a 5 gallon mash and ad 15 gallons of water you still only have 1 gallon of alcohol available to pull out.... Make sense?

If you want easier cuts more available alcohol is the answer. Bigger mashes.
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Re: Head space in a still

Post by StillerBoy »

Tx Mike wrote: Wed May 12, 2021 3:43 am 've got aQ i cant find a direct answer for, I've got a 20g pot i use for my pot still, i ran a 5g mash through it and had a hard time with cuts,
The issue you have run into is due to the very small of alcohol available for 5 gal wash and even less from a mash, if it was a mash..

Not knowing what the abv of the batch what, but taking a guess at 10% abv, that would potentially give about 100 ml of pure alcohol per litre or 2L at best.. but it is not possible to exact that level of purity during a run especially when using a pot still setup...

So at best you should of first strip the alcohol from the batch, then run it a second time... but due to the low level of alcohol, even if it was stripped first, the making of cut will be very difficult..

As has already been expressed, stripped multiple batches, then with the large volume, make a spirit run (a second run), which should able you to smell, and taste the different during the run..

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Demy
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Re: Head space in a still

Post by Demy »

I often do small quantities so I know what you mean .. you have to learn how to manage them. In most cases with small quantities it is necessary to stripping before the final distillation so as to raise the alcoholic degree and allow you to make good cuts. Small quantities with an alcoholic degree underneath we say 10% are difficult to make the cuts because your alcohol will be spreader, so you will get few hearts the rest of your alcohol will be contained above all in the queues. This is my experience.
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Re: Head space in a still

Post by OtisT »

Mike. Another factor making cuts difficult for you is that you could be running too fast (too much heat). From my experience running batches from 2 gallons to 13, you can’t run a pot still with 1/4 the volume in 1/4 the time of a full boiler. I’m talking about time producing, not counting warmup. There is a possibility that running that batch slower will give you better separation and a better shot finding a good cut.

My observation on this is why I cringe every time I see someone recommend you run with a pencil lead sized stream. That in itself means nothing if you don’t take batch size into account.

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Re: Head space in a still

Post by Deplorable »

Otis, you bring up a good point. Something I've wondered about recently. Many members here run 10 gallon spirit runs and claim a run time of around 6 hours for a "pencil lead sized stream"
So what's the stream size or run time for a spirit run of half that volume of the same abv low wines?
My spirit runs average around 6 gallons of 30-35%, and take about 5 to 6 hours from heat on to heat off. So about 4 to 4.5 hours of production.
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Re: Head space in a still

Post by StillerBoy »

Deplorable wrote: Wed May 12, 2021 1:05 pm So what's the stream size or run time for a spirit run of half that volume of the same abv low wines?
My take is that once the low wine is up to temp, meaning at the first drop, then the output or take off rate is managed by the amount of power used.. being that I prefer to manage the power by using ml per min vera telling someone to run a stream size..

From experience, it does not matter what size of a load or abv it has, the take off rate should be always the same.. only the overall amount of time of the run will differ.. so one can regulate to head speed, increase slightly for the body, that way one has a uniform manner of reduplicating a run..

That has been my experience, both in pot still mode or reflux column mode.. milliliter (ml) per min is the gauge I use..

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Re: Head space in a still

Post by OtisT »

Deplorable wrote: Wed May 12, 2021 1:05 pm Otis, you bring up a good point. Something I've wondered about recently. Many members here run 10 gallon spirit runs and claim a run time of around 6 hours for a "pencil lead sized stream"
So what's the stream size or run time for a spirit run of half that volume of the same abv low wines?
My spirit runs average around 6 gallons of 30-35%, and take about 5 to 6 hours from heat on to heat off. So about 4 to 4.5 hours of production.
The best example I can give at this time is that when I am doing a 2 gallon spirit run, I need to run a very broken stream or I get smearing all the way through. Getting close to a small but steady stream is still too fast and I back it down a bit from there to steady spurts. Running 12 gallons of low wines, I am running a solid stream that looks about the size of an old school wooden pencil lead. My 2 gallon run is not even close to 1/6 the run time of my 12 gallon run.

I don’t think a spirit run takes a set time regardless of the charge size, and I don’t think time is directly proportional to charge size either. I feel it is somewhere in between.

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Re: Head space in a still

Post by Deplorable »

My take is that once the low wine is up to temp, meaning at the first drop, then the output or take off rate is managed by the amount of power used.. being that I prefer to manage the power by using ml per min vera telling someone to run a stream size..

I agree that power (or heat) to the boiler should be used to manage the take off rate. And the take off rate should be controlled in a manner that minimizes smearing. Just talking pot stills here, my limited experience has been that I can get the best heads compression running at a 3-5 drips per second, then increasing the power gradually after the first 5-600ml to a very thin stream that is easily disrupted to a broken stream when the jars are changed. (more like a mechanical pencil lead size) I find that if I run at a thicker stream, my tails cut is significantly larger.
The best example I can give at this time is that when I am doing a 2 gallon spirit run, I need to run a very broken stream or I get smearing all the way through. Getting close to a small but steady stream is still too fast and I back it down a bit from there to steady spurts. Running 12 gallons of low wines, I am running a solid stream that looks about the size of an old school wooden pencil lead. My 2 gallon run is not even close to 1/6 the run time of my 12 gallon run.
This confirms my assumptions that with a larger charge you can run at a faster take off rate, I assume due to the shear volume of the fractions in the boiler. So telling someone to run a certain sized stream without knowing the volume of the charge can be leading someone with a small still or small charge in a larger still down a path that may not give them the best results?
This is where one can only learn by running their still and learning what the still and spirits want through repetition.
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Re: Head space in a still

Post by Tx Mike »

Thanks y'all,
My initial abv was 16%, it was 5%after a 10 day fermentation, i used flaked corn, 6 row and corn sugar for the mash,
I ran it slow, took 4 hours and my stream stayed between a pencil lead and drips, any lower it was a drop per second or less and that seemed way to slow.
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Re: Head space in a still

Post by Tx Mike »

I'm looking for a smaller pot to use to re-run it. It didn't come out horrible but i know it could have been better. I threw out the first 4oz and stopped collecting @ 110pr, i ended up with 3quarts of 143pr that i brought down to 80pr. I'm thinking i should have threw out 8oz i can tell there's a little heads that made it through, i can catch the slightest whiff of hand sanitizer/tequila, as far as taste, it's corn flakes with alcohol instead of milk, if that makes sense
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Re: Head space in a still

Post by Saltbush Bill »

Tx Mike wrote: Thu May 13, 2021 2:39 am My initial abv was 16%,
Are you saying that the wash ABV was 16% ?
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Re: Head space in a still

Post by Tx Mike »

Saltbush Bill wrote: Thu May 13, 2021 3:04 am
Tx Mike wrote: Thu May 13, 2021 2:39 am My initial abv was 16%,
Are you saying that the wash ABV was 16% ?
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Re: Head space in a still

Post by still_stirrin »

Tx Mike wrote: Thu May 13, 2021 2:39 am...My initial abv was 16%...
...it was 5% after a 10 day fermentation...
Huh?

Do you mean the O.G. was 1.123 (16/130=0.123)???
... And now the S.G. is 1.038 (5/130=0.038)???

That would indicate your hydrometer readings were for “alcohol potential”, not actually the %ABV of the wash. The alcohol is actually proportional to the reduction in the specific gravity (which indicates the density change resulting from reduction of the sugars present).

But....an O.G. with the potential that high is not healthy for the yeast, so it likely won’t drive all the way down and will leave residual sugars in your wash. In other words, an unhealthy environment for the yeast means they won’t do their job properly, often producing bad flavors and higher alcohols and crap in your liquor. Plus, you’re wasting some of your money on sugar that isn’t successfully transformed into alcohol.

Again, the number you quoted is confusing as to what you actually have fermented. The difference between OG and FG (final gravity) suggests your wash is only 11%, or so....although that is still on the high side of goodness. And indicative of the yeast’s ability to produce alcohol.
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Re: Head space in a still

Post by Tx Mike »

It was 1120 maybe 1119 sg before and 1022sg after fermentation
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Re: Head space in a still

Post by Tx Mike »

So I'm gathering i should dilute what i got to at least 80pr, re run it and pay close attention to the heads..... now that i know what they small and taste like.
I'm gonna do this in a smaller set up, something in the 8l range
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Re: Head space in a still

Post by StillerBoy »

Tx Mike wrote: Thu May 13, 2021 6:48 am It was 1120 maybe 1119 sg before and 1022sg after fermentation
The numbers provided are an indication that the ferment was started with way to much sugar, and it never finished dry..

A sugar wash for for best flavor should never have an SG of more than 1.070 or about 175 - 190 gr per liter..

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Re: Head space in a still

Post by Saltbush Bill »

To put it simply, you should keep the abv of the wash lower
High abv stresses the yeast and makes for bad tasting booze.
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Re: Head space in a still

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And stinky hand Sanny :ewink:
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Re: Head space in a still

Post by SaltyStaves »

Tx Mike wrote: Thu May 13, 2021 7:03 am So I'm gathering i should dilute what i got to at least 80pr, re run it and pay close attention to the heads..... now that i know what they small and taste like.
I'm gonna do this in a smaller set up, something in the 8l range
Forget this. It will not fix any of your problems.
You fermented too little wash at too high a proof and tried to pass it once through a pot still. Its basically a text-book example of what not to do. Sack your mentor. They've done you a huge disservice.

The solution is simple. Ferment more. Don't stress the yeast. Do multiple stripping runs until you have enough low wines to do a spirit run.

A smaller boiler for smaller runs or spirit runs will certainly serve its purpose, but right now, you should address the problems in your process.
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Re: Head space in a still

Post by Tx Mike »

Alright, throw it out, got it. I'll come up with a smaller set up and try to keep sg below 1070, no sense in wasting 3X more mash per run if it messes up again.

Thanks for all the help, y'all
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Re: Head space in a still

Post by NZChris »

Don't throw it out. Water it down to 40% and run it again, but use Kiwistiller's Guide to help you make the cuts.

https://homedistiller.org/forum/viewtopic.php?t=13261
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Re: Head space in a still

Post by Tx Mike »

NZChris wrote: Thu May 13, 2021 10:14 pm Don't throw it out. Water it down to 40% and run it again, but use Kiwistiller's Guide to help you make the cuts.

https://homedistiller.org/forum/viewtopic.php?t=13261

Cool, thanks
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Re: Head space in a still

Post by Tx Mike »

Prepping for round 2.
I have 10g of corn/sugar mash fermenting, Og of 1060.
I modified the lid by cutting a 8 inch hole and fastening a 4q pot on top of it, this should help funnel the vapors making it easier for them to escape in some sort of order. It should be ready to run by the weekend. I'm hoping 10g will be easier to cut and help alleviate the issues from the last run. i will have to get more carboys to ferment more than 10g at a time

I did find that going to the feed store is a LOT cheaper for corn, got a 50lb bag of clean cracked corn for $13.00.
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Re: Head space in a still

Post by Tx Mike »

Last weeks run came out better.
Changes made were the 4qt pot on top with an 1.5 inch fitting for vapors to escape. I made and used a 30 inch long ¾/½ inch liebig condenser instead of a coil. As far as the mash goes, i used cracked corn and amylase instead of flaked and 6 row. I still ran 5 gallons at a time. (one had molasses because i ran out of sugar for it and needed to get the og up, it had a puke smell for a couple days of the fermintation, it fermented out fine) put a empty pot with a lid in the middle, (weighted down of course).
Also waited until the pot reached 150° before i put the lid on. The modified set up ran good with a nice drip to broken stream run. I collected in 300 ml increments down to 60pr, not any noticeable foershots but still tossed first couple of oz. Did this with both runs, i mixed em together and ran that once through a 16q pot i made for the stove top. Ended up with 3q of 140pr. It's not as sweet and corny as the first run with the 6 row and higher og, that first run was 160 and was not as "hot" in the mouth and nose.

It was cool paying attention to the feel, smell and taste of the liquor at various places in the run all the way to the Sweetwater at the end.
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