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Temperature control with a PSII in Pot Still configuration
 Rank: Junior Member Groups: Registered
Joined: 9/14/2012(UTC)
Posts: 12
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"Thanks in advance for the help. I am having trouble maintaining a stable temperature. I put the wash in the PSII and start the heat source on medium flame. Starting temperature at the top of the column to start is approx 70 degrees. The temperature at the top of the column rises slowly for 15-30 minutes to approx 81 degrees. It remains steady for 5-10 minutes at 81 degrees and then begins to increase at a increasing rate and rises rapidly to 197 degrees and holds at 197 for as long as I maintain heat. I begin to get a steady stream at approx 163 and it continues and eventually runs out. Data points:
- I am at approx 6500 ft altitude and a local boutique distiller says Ethanol vaporizes at 163 at this altitude.
- I am using a PSII in a pot still configuration.
- This is run of 3 gallon (2gal-H2O, 1gal-cheap wine) run for test purposes twice with very similar results.
- I am using a turkey fryer gas burner as a heat source.
- On the first run I ran it at a steady flame throughout the run.
- On the second run, I reduced the flame significantly upon reaching 81 degrees.
My intent was to attempt to run up the temperature to 165-170 and hold that temp for a period of time. Question: Is the accelerating temperature a normal occurance? Is the acceleration past my target temp a matter of controlling the heat source better? Does the type of wash change the temperature swings in any significant way? Thanks again."
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 Rank: Senior Member Groups: Registered, Moderator
Joined: 7/25/2009(UTC)
Posts: 2,209
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Keep your applied heat to just enough heat to just allow a slow drip. The alcohol controlls the temperature. If you try to control the head temp you are chasing temperature.
As the diferent factions appear you will get higher head temperatures
Are you able to turn down the heat low enough to control the drip?
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Rank: Senior Member Groups: Registered, Moderator
Joined: 4/14/2010(UTC)
Posts: 1,666
Was thanked: 15 time(s) in 15 post(s)
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"I read your useing gas and that can be diffucult to control heat. You'll find that after heatup and whilst your cooking very low heat is what will do best. Of course if you want to really push it then turn up the fire. Remember out of the wind is best because that little flame WILL go out. Thats just the nature of useing gas. So be carefull.
You'll find that water will indeed be different stillin that an actuall wash or mash as water takes more heat and then your trying to boil water where with a wash your trying to get that just right temp which is somewhere in between."
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Rank: Junior Member Groups: Registered
Joined: 9/14/2012(UTC)
Posts: 12
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Thanks Heeler, so I am reading your response as, start looking for a hot plate and meter".
Scotty- I have not been able to control the drip by adjusting the flame. In both test runs the temps has stalled at 81 then raced past 160 in a matter of seconds.
I am taking your comments as indications that I am running up the temp to 81 too fast and the residual energy produced drives the temp up too fast in the critical ranges. My next attempt I will try and raising the temp slower with a low flame from the beginning.
Given your comments about gas, what is a high quality choice for an electric heat source with good temp control. I have seen the BH hot plate and the mod to eliminate cycling. I was hoping to find a local product. say at WalMart, and modify the same way. the part I am not sure of is the control box that adjusts the electrical input. Or is the control box necessary?
I guess I am asking waht are some real world heat source solutions?
Thanks again,
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Rank: Guest
Groups: Guests
Joined: 2/10/2002(UTC)
Posts: 5,254
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Dont think your going to find anything useable at Wally World but could be wrong..just aint never seen anything there which looked like it might work. If you go the hot plate route..after bypassing the thermostat.. you will need some control of it which normally comes in the form of a RSC (router speed controller). Twenty bucks or so at Harbor Freight. Might as well get two or three because they get hotter than a two dollar pistol and dont seem to last long.
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Rank: Junior Member Groups: Registered
Joined: 9/14/2012(UTC)
Posts: 12
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Thanks BW. I looked up the RSCs and that seems like a workable alternative. I guess my question for you, Scotty and Heeler is what are you using and why?
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Rank: Junior Member Groups: Registered
Joined: 8/7/2012(UTC)
Posts: 86
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"I'm using a modified 1500 watt hot plate from brewhaus. It is a sturdy hotplate. Your 1500 watt hotplate will draw 12.5 amps at full. I bought a 23 amp RSC so i will never have trouble with it. They all get hot because they use the resistance in series principle to controll the applied voltage and thereby reduce the wattage of the hotplate.
Dont by a cheap marginal RSC or you will have trouble. When you are making a run, they are on for hours at a time. Mine runs from 10 to 14 hours at a time.
There are no hotplates large enough at the super stores and besides the bh one is made extra sturdy."
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Rank: Guest
Groups: Guests
Joined: 2/10/2002(UTC)
Posts: 5,254
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The commonly available cheap RSC's are generically known as Triacs. I have two 26 amp models branded Rockler..one is fried and the other still unopened in the box. They are made in China like most of the rest and dont seem to last very long but Rockler has great customer service and will send you another without any hassle. About 60 bucks seems like. Would be surprised if somebody rated it superior to the el cheapo model from Harbor Freight. A better choice for them with money is called a Variac. You can plug that into google and go to their website if you want to check em out. Since realizing pot stilling was not my cup of tea and gravitating toward refluxing I dont use any control at all other than the cooling water..of which there is more than plenty to knock down all the excess heat which the hotplate can produce. Hope this helps. Originally Posted by: readk  Thanks BW. I looked up the RSCs and that seems like a workable alternative. I guess my question for you, Scotty and Heeler is what are you using and why?
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Temperature control with a PSII in Pot Still configuration
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