Vapor Temperature On My First Run

[Slipstreem]

Was hoping someone could give me some insight on the temperature readings during my first cleaning run.
I made up a turbo sugar wash which I fermented to about 10%, and decided to use this as a cleaning run for my new reflux column still. There are 2 temperature gauges (one in the pot, and 1 at top just above the deflagmenter). See attached.

I got the pot temp up to about 180-190 and noticed a fairly constant drip being produced, and later tested the product in samples of 250ml. They were consistently around 120-150 proof with no reflux. What puzzled me, is the vapor temperature never rose over about 145. I had assumed I would be seeing this rise to over 170+ as this progressed. Is this normal? I decided to continue by ignoring the temperature reading, and adjust my heat to finish the process.

[juana_b]

Good on ya for ignoring it.
I suspect those thermometers have not been calibrated.

[shadylane]

..... Is this normal? I decided to continue by ignoring the temperature reading, and adjust my heat to finish the process.

Yes, it's normal for thermometers to be inaccurate.
As you've discovered, it's best to run the column based on take off rate.

[Saltbush Bill]

As above , its a waste of time and will just confuse hell out of you .....its on there as a marketing tool, helps sell stills to those who know no better.

[Salt Must Flow]

When doing a reflux spirit run with a packed column, the vapor temp will rise then stabilize. During the run, you'll only see changes in temp within a couple 1/10th degree F. Once you hit tails the temp will spike. That is why I prefer digital thermometers that have 1/10th degree resolution. Thermometers are not required to run a still, but they can be very helpful. My controller has a RTD temp probe and reads temp in 1/10th degree resolution so I use it. I can set temp alarms so it can alert me when vapor begins to rise through the base of the column. I can move the probe to the top and it will alert me when reflux has started.

During a stripping run or when doing a spirit run with a pot still, the vapor will travel up the riser, the temp will rise and slowly continue rising throughout the entire run as alcohol is being removed. For this an analog thermometer could be considered ~ ok, but still digital thermometers with 1/10th degree resolution are more versatile. Once again you don't need a thermometer, but like being able to see what the vapor temp is.

[richard1]

Nonsense. I run a LM still. You manage the entire process by temperature at the uppermost take off point. Forget the kettle temp., that's just for info. You monitor Ethanol BP, to fores, heads, hearts and tails. Take plenty samples for tasting (in jars) noting take off temp. during heads into hearts and similarly hearts into tails. In future if you do the same recipe, you simply do the cuts at the same temperature.

[squigglefunk]

cuts by temperature eh?

[zed255]

When I'm in reflux mode, no matter whether LM or VM, I only note two distinct temperature changes / phases. They are just landmarks and not cut points.

At start up, the temperature will spike on first vapour, then settle to a minimum point once refluxing begins and the column 'stacks', after which I draw off my fores and early heads. The temperature will creep up during the withdrawal of the fores and early heads until it again stabilizes. At this point I switch to cuts jars as there will still be some heads despite a stable temperature.

The whole run will stay at this temp until I have almost depleted the alcohol from the boiler, at which point the temp will creep by 1/10th of a degree C signalling that tails have arrived. A short while later the temperature begins to creep 1/10th of a degree at a time more frequently where I shut down. I'm shut down by the time I'm only about 0.5°C over the stable temp of the bulk of the run.

I never use the actual temperature as a reference since even barometric pressure can affect it, but rather the change in temperature.

[Saltbush Bill]

A lot of talk of LM and VM stills above.....The still in question is a CM.

[shadylane]

There are 2 temperature gauges (one in the pot, and 1 at top just above the deflagmenter).

I'd run the still with water in the pot, just to see how far off the thermometers are from 212f
I'd also check to see if the scale rotates to calibrate the thermo.