Pot Still Vapor Temperature

Other discussions for folks new to the wonderful craft of home distilling.

Moderator: Site Moderator

User avatar
Corsaire
Site Donor
Site Donor
Posts: 1085
Joined: Tue Jun 20, 2017 1:20 pm
Location: Belgium

Re: Pot Still Vapor Temperature

Post by Corsaire » Sun Aug 02, 2020 1:28 pm

Brew bama wrote:
Sun Aug 02, 2020 10:49 am
jedneck wrote:Adding power is not adding heat
???? Image I give up.

Running power thru a heating element produces heat. A heating element converts electrical energy into heat through the process of resistive (otherwise known as Joule heating). The electric current passing through the element encounters resistance, which produces heat.
Of course power produces heat, but that doesn't neceserily increases temperature.

Look at it this way:
If you boil water it turns to steam, but the water stays at 100C.
You can throw more power at it, turn up the gas, throw another log on the fire, whatever. All it does is increase the rate steam is produced. The liquid still holds 100C.

In distilling you don't manage temps, you manage vapor production.
In a pot still the rate of vapor produced dictates how much smearing happens.
In a reflux column it contributes to reflux ratio.

Add to that that yes, pure ethanol boils at whatever science books dictate but if you add other compounds to the mix all sorts of crazy bonds happen.

User avatar
Hambone
Swill Maker
Posts: 218
Joined: Sun Jun 07, 2020 7:24 am
Location: MO, just around the bend...

Re: Pot Still Vapor Temperature

Post by Hambone » Sun Aug 02, 2020 1:35 pm

Does the PID work better with glass thumpers or silicone gaskets?


Lord, I apologize for that comment....
Good judgement is the result of experience.

Experience is usually the result of bad judgement..

kimbodious
Trainee
Posts: 873
Joined: Fri Apr 17, 2015 3:57 pm

Re: Pot Still Vapor Temperature

Post by kimbodious » Sun Aug 02, 2020 1:44 pm

Great clear concise explanation Corsaire!! It should be required reading.
--
50L Beer keg boiler, 2200W element
Modular 2" Pot Still
Modular 2" CCVM

User avatar
bluefish_dist
Site Donor
Site Donor
Posts: 1135
Joined: Fri Jan 16, 2015 10:13 am
Location: Cos

Re: Pot Still Vapor Temperature

Post by bluefish_dist » Sun Aug 02, 2020 2:34 pm

Brew bama wrote:
Sun Aug 02, 2020 7:22 am
I guess we simply agree to disagree.

Not sure how bumping up a PID controller is any different than turning up heat any other way, manual or otherwise, but OK.
It’s not, but it’s horribly inefficient.

Why have a PID then change the set point to keep the rate of vapor production the same? The whole point of PID is to control a process at a set temperature. Unfortunately this doesn’t exist is the process of boiling wash/wort. The boiling temperature of a wash/wort is constantly changing and it always goes up. Because of this the power input is always going down. To overcome this, the user has to keep increasing the temperature set point to keep the same vapor production rate.

Controlling power input almost directly controls the rate of vapor production which is proportional to vapor speed in the column. There are slight changes since alcohol and water don’t require the same amount of energy to change phase, but it’s close enough we can ignore this. If using wash/mash boil temp it might change 15-30 deg during a run. That’s a lot of adjusting on a PID to do something that requires no adjustment using a power meter.
Formerly
Dsp-CO-20051

Brew bama
Novice
Posts: 41
Joined: Mon Jul 27, 2020 10:45 am

Re: Pot Still Vapor Temperature

Post by Brew bama » Sun Aug 02, 2020 3:10 pm

bluefish_dist wrote:
The boiling temperature of a wash/wort is constantly changing and it always goes up. Because of this the power input is always going down. To overcome this, the user has to keep increasing the temperature set point to keep the same vapor production rate.
^^^^ Exactly. ^^^^

This works like a charm. Is very easy to do. Makes the process interactive. ...and is fun.

Why anyone other than me would give two craps how I make what I have work to the extremes this has taken is hilarious. Image

Take it easy folks. Have fun and don’t take this so serious.

Cheers!

User avatar
LWTCS
Site Mod
Posts: 11370
Joined: Mon Jan 26, 2009 6:04 pm
Location: North Palm Beach

Re: Pot Still Vapor Temperature

Post by LWTCS » Sun Aug 02, 2020 3:41 pm

Extreme?
Not extreme at all.
Fact is , more or less daily fodder (more recently).
It's why we're here no? To talk about all things distilling.

You wanted us to be part of your education and journey or you wouldn't have posted, no?
It just sounds like you weren't expecting to be called out by the self policing community.
Trample the injured and hurdle the dead.

Brew bama
Novice
Posts: 41
Joined: Mon Jul 27, 2020 10:45 am

Re: Pot Still Vapor Temperature

Post by Brew bama » Sun Aug 02, 2020 3:43 pm

LOL. Ok.

Your world. I’m just hangin out in it.

User avatar
bluefish_dist
Site Donor
Site Donor
Posts: 1135
Joined: Fri Jan 16, 2015 10:13 am
Location: Cos

Re: Pot Still Vapor Temperature

Post by bluefish_dist » Sun Aug 02, 2020 3:59 pm

Brew bama wrote:
Sun Aug 02, 2020 3:10 pm
bluefish_dist wrote:
The boiling temperature of a wash/wort is constantly changing and it always goes up. Because of this the power input is always going down. To overcome this, the user has to keep increasing the temperature set point to keep the same vapor production rate.
^^^^ Exactly. ^^^^

This works like a charm. Is very easy to do. Makes the process interactive. ...and is fun.

Why anyone other than me would give two craps how I make what I have work to the extremes this has taken is hilarious. Image

Take it easy folks. Have fun and don’t take this so serious.

Cheers!
We are just trying to help you from wasting time and $$. Come back after a few hundred runs and let us know if you still run this way.

IMHO a simple power controller is awesome. Simply use as much power as you have for heat up, then back off to start your run and not puke. One whole adjustment, no tweaking required. No need to figure out what temperature is required to boil the abv in the boiler.
Formerly
Dsp-CO-20051

User avatar
Corsaire
Site Donor
Site Donor
Posts: 1085
Joined: Tue Jun 20, 2017 1:20 pm
Location: Belgium

Re: Pot Still Vapor Temperature

Post by Corsaire » Sun Aug 02, 2020 4:07 pm

If you have fun with it then it's all good.

But if you can, just swap out the pid for a power controller and see if you notice a difference. Just for shits and giggles.

I get being inefficient. I used to commute an old honda bike that needed oil changes every 3000kms and still had points ignition. Kick start only too.
Still love that thing.

Problem is a lot of new distillers get sucked into the temperature trap and think a pid is the best possible controller, which it isn't.

User avatar
NZChris
Master Distiller
Posts: 8892
Joined: Tue Apr 23, 2013 2:42 am
Location: New Zealand

Re: Pot Still Vapor Temperature

Post by NZChris » Sun Aug 02, 2020 4:21 pm

There's been a lot of newbie PID owners coming here since a newbie started posting distilling videos on Youtube without bothering to do his homework first.

Brew bama
Novice
Posts: 41
Joined: Mon Jul 27, 2020 10:45 am

Re: Pot Still Vapor Temperature

Post by Brew bama » Sun Aug 02, 2020 4:29 pm

@bluefish_dist
@corsaire

I don’t doubt one and done power is a better deal but it’s just not in the cards right now. Maybe later. Until then I have to run what I brung.

Cheers!

User avatar
NZChris
Master Distiller
Posts: 8892
Joined: Tue Apr 23, 2013 2:42 am
Location: New Zealand

Re: Pot Still Vapor Temperature

Post by NZChris » Sun Aug 02, 2020 4:39 pm

Some PIDs come with the option of manual control of the output. Check if yours does.

Post Reply