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The subject of relevance of a thermometer in a potstill is debatable. I start everything I do with the idea of doing it the hard way or the traditional (old school) way of doing it. I approached this craft in the same way, but soon found myself having problems. I told myself that I didn't need a thermometer in my potstill, that I would make cuts based on taste and smell as the old timers did. I quickly found my cuts and runs difficult to figure out. I finally capitulated and installed a thermometer in my lyne arm and have thoroughly been thrilled with the help it gives me, notice I said help and not does everything for me.

The use of the thermometer aids me in the following ways:
#1- it gives me an idea of the ambient temperature starting the run.
#2- it gives me an idea as to when the first drops will begin falling and I can be there to monitor it with all my attention as the fores are the most volatile part of the run.
#3- it helps in knowing what point I am in in the run coupled by taste and smell and even feel. The parent site and some topics in this forum cover those quite extensively as well as the temps associated with cut points of a run which are a guide line more than instruction manual sometimes.
#4- it helps me to know when my run is finished or a waste of time to proceed further as the energy put into the wash is more than the gain.

The first thing to do is to check the accuracy of your thermometer. As some instruments have a greater innacuracy ratio the higher the scale you can and probably should check it at 2 points, I check mine at 100*F against a know good oral thermometer from the pharmacy, it should be pretty darn close. Next I check it at the boiling point of water which at sea level is 100*C or 212*F, higher altitudes will be lower temps but I think Denver which is 1 mile above sea level is 95*C so there is a difference. If your thermometer cannot be calibrated then simply make notes of the differences and calculate them into your readings.

For the part of running the still and using the thermometer you should do a couple of runs and keep good notes as to temperatures etc. I know I get first drips at 140*F on my still, every time like clockwork. I know based on reading from the parent site and experience that there's no use in tasting anything below 180*F or so and usually don't even think about it until 190*F. I then get into what I call the heads, that's just me so don't lock yourself into that, alot of this craft is personal experience and theory based on knowledge at that time. From there it's up to 192*F where things start to mellow out and the abv starts a consistent drop thru out the run to the tails. Again from reading on the parent site and some backwards experience I have found that I begin to get tails coming through at around 202*F and from there I run to around 208*-209* depending on how far I've decided to go into tails.

All of which I take into consideration along with the alcoholmeter in the parrot taking notes constantly of time, temp, abv%, smell and taste. I determined what tails smelled like in the beginning by running a wash down to 20% from a 71% starting point being absolutely certain that what I was getting was tails, then worked my way back up the collection jars testing for that same odor however faint. But abv% on tails is relevant to the wash itself and the still, if you start a strip run at say 48% and go down to 30% you may very well not be into tails yet (in my experience) you may very well still be into the flavorful part of the run but you may be getting close to tails. Seems to me that temperature is the biggest constant through the different runs cause 200* is 200*, different wash types such as fruits and grains will have different cut off points which require some reading and experience to pin down for your operation.

Thermometer placement should be at the closest point to the lyne arm (IMO). I installed mine actually extenting through the column into the lyne arm before the condensor start point. This gives me a good idea of what the temps are before the condesation point at their warmest temp. in the process.

My overall analysis and sometimes not so humble opinion is that for novices or newbies while it is not by any means required, a thermometer in the still head does aid in different ways in the learning process. It helps with my cuts and efficiency or economy of my runs in that I can lower input temps or increase to get the most efficient vaporization and speed of run. I hope this helps someone else in their build decision as to incorporate a thermometer or not. It's all personal preference but I find it more helpful than anything. Again, it requires some homework on your part but I think you'll be better off in the end.

TRTH

Thanks TRTH,

This is great info for a novice like me.

Good words, trth. Nothing wrong with using a thermometer as a guide, just as long as you don't rely entirely on it and use your smell and taste as well.

Well said TRTH!

I, like you, set out t do it the old fashioned way on the weekend. And whilst it wasn't a total failure, for a newby the cuts are not quite as easy to pick up as you would hope.

I bought a thermometer and heat proof bung first thing yesterday.

Honestly, I put a thermometer into my still and have only used its alarm to alert me when I need to be paying attention. Other than that, I don't use it at all. It seems to have no relevance to the distillation process. It almost seems strange to associate the head temperature with the distillate coming out. I would bet my bottom dollar that a novice with a spoon could make better cuts than a novice with a thermometer. Personally, I am thinking of taking it out of the still as it's a pain in the ass to keep the cork in proper condition. Also Aussie, I hope that bung you got is made of cork right?

Centimeter wrote:Honestly, I put a thermometer into my still and have only used its alarm to alert me when I need to be paying attention. Other than that, I don't use it at all. It seems to have no relevance to the distillation process. It almost seems strange to associate the head temperature with the distillate coming out. I would bet my bottom dollar that a novice with a spoon could make better cuts than a novice with a thermometer. Personally, I am thinking of taking it out of the still as it's a pain in the ass to keep the cork in proper condition. Also Aussie, I hope that bung you got is made of cork right?

From my reading of the post, I understood that the thermometer was only being used as an alert for when somethin was close to happening, a bit like you using your alarm.
The cuts were still being made with the use of a parrot, smell & taste.

I may be wrong - but that was my assumption.

Cheers.

Centimeter wrote:Honestly, I put a thermometer into my still and have only used its alarm to alert me when I need to be paying attention. Other than that, I don't use it at all. It seems to have no relevance to the distillation process.

I don't agree. I think it is a good idea for novices to see how vapour temp changes with the smell/taste of the spirit. It is another aspect of the distillation process that is worth knowing about. As long as you do not use temp as your main guide to making cuts.

I do agree that thermometers with programmable alarms are VERY useful, particularly for safety alerts. I always use them.

Yeah Centimeter that was my point to the post. Since the thermometer won't be partaking of any of the outcome I make cuts based on taste, smell and feel and use the parrot to gauge what that's probably going to be like before I taste and use the thermometer as a guide. It is mostly useful for the tails transition, or at least that's what I find, as I know as stated that above 202* +/- 1* I had better keep a nose to the drip point for tails. I don't use it as such but since the higher alcohols vaporize at a lower temp you could also use it to be fairly sure that you're out of the foreshot range also if you're not running too fast. Again, it's what ever you're comfortable with I just basically stated what I found in my experience to maybe help some one else starting out because you're first couple of runs you have no idea what fores, heads and tails smells like and abv doesn't tell you jack on that without some experience on the still and the washes.

I think I could run my pot without one, but I keep a log for each run.
I include: amount in ml, ABV, temp and time for each lot. Also add comments for taste and smell for spirit runs. After it's aired out for a day or two, I also add comments on final cuts. Most of my strip runs, I've seen that I drop about 5% ABV for each 0.5*C rise and approx 400ml collected. Doing a reflux run, a 0.5*C change in temps puts me into the tails.

What I'm about to say has been said many times before, but there are a new crop of new distillers here so I'll say it again:

Anyone new to distillin' that runs a potstill and tries to make cuts based on a thermometer readin' is goin' to have a heap of frustration and crappy spirit. The temp is based on so many influences and is changed so easily by things that ya can't controll, like barometric pressure, that tryin' to duplicate results is basically impossible.

The BEST way to make cuts is with yer nose and toungue. What about folks that are new to this all and don't have the experience? They would do well to make cuts based on ABV%.

Makin' cuts based on a hydrometer readin' is easy and able to be duplicated. If ya made a specific wash/mash and the cut from body to tails was at 100 proof, the same wash/mash will again have the cut at the same proof. From day to day the thermometer readin' will be different.


As I said before this info is for potstills... a thermometer is an important tool for a column still, but about as necessary for a potstill as a turn-signal.





I wish yall luck.

I agree on that -unless is done under laboratory conditions its hard to duplicate. that extra oz of grain, extra sugar from fruit changes your wash and
that will Chang how the pot will run also alcohol boils at 78.3 c at sea level not in the mountains, not under high barometric presser not on a cold
rainey day etc

I have a thermometer just right before the liebig condenser. I've found once I made my chart correlating temp vs. ABV of distillate output it's pretty darn accurate all the time.

That being said, I don't use temperature or ABV of distillate to determine my cuts. The best way to learn is practice and collecting in small jars samples through out the run and contrasting and comparing the samples after you have finished. I still collect in small jars. Tasting a smelling what's coming out and comparing to what came out 15 minutes ago really teaches yourself the nuances of how the flavors and smells progress through out a run.

I don't use a hydrometer at all during distilling - only for diluting to 40%ABV afterwards.

I use the thermometer at the beginning and end of the run. At the beginning when the temp starts to rise quickly I consider everything that comes out of the still until the temp has stabilized to be foreshots. On a stripping run output will start to drip at about 45C and depending on the ABV of the wash it will rise quickly to about 91-92C and then it will stabilize and rise slowly. So from 45C to 91-92C are foreshots. On my 12L boiler, it usually is about 50ml or so that has been collected.

I use the thermometer at the end of the run to know when to stop collecting. I can quickly see the ABV of the output - at 98C it's about 10% or less. So at 98C on my still, I shut her down and I'm done. If I'm making vodka I shut it down sooner to collect less tails.

GBM, I'm just tryin' to make it easy for the new folks.

Alot of them seem to think they can make a body or tails cut based on temp, and that just ain't so. As I allready stated the BEST way is based on smell and taste. But if yer familliar with yer still and the recipe, you CAN make cuts based on ABV% and get decent cuts without ever smellin' or tastin' the distillate. I dare say it can't be done with a potstill and a thermometer.

theholymackerel wrote:But if yer familliar with yer still and the recipe, you CAN make cuts based on ABV% and get decent cuts without ever smellin' or tastin' the distillate. I dare say it can't be done with a potstill and a thermometer.

I don't recall saying I made my cuts based on ABV. Maybe my post was not clear enough. Oh well, shouldn't have spent the time typing it in.

GingerBreadMan wrote:I don't recall saying I made my cuts based on ABV. Maybe my post was not clear enough. Oh well, shouldn't have spent the time typing it in.

Where did I say that ya did?

My mistake, I must have saw an extra word in your post. Thought you said 'if you can make cuts based on ABV..."

Aparently there is no 'if' in your post. I must be getting old and seeing stuff.

Humm...

I don't know where this went wrong, and I'm more confused than ever.

Plain Speak:
(1) I'm not tryin' to give ya a hard time.

(2) I want the new folk here to understand that with a potstill ya can not make good cuts with a thermometer, but ya can make ok cuts with a hydrometer (if yer familiar with yer still and recipe).

(3) The BEST way to make cuts is based on yer sence of taste and smell.









Ok. Hopefully the misunderstandin' are over, and ya know I'm not messin' with ya.

If ya disagree with anythin' I stated above, say it, and let the conversation continue.

I apologize for typing this on a blackberry ahead of time.

The purpose of my post was to basically help brand new folks determine what heads and tails smell like to begin with. As with everything in this craft experience is best but the nature of the craft does not afford folks an opportunity to start under direct personal mentorship of an experienced veteran of the arts. That being said, everyone look back, if you can remember that far, lol, to your first run and tell me you already knew what heads and tails smelled and tasted like. I might not have made the post clear in saying that the thermometer does not make the cuts for you, it simply aids in learning what to cut out and what to keep in. All of which I based on my personal experience and theory of distillation based on book knowledge.

The only thing I'll disagree with, is the idea that temperature and ABV output are not the same.

A well placed thermometer right before the liebig condenser will give an accurate reading of ABV. Once you've made a chart of temperature and ABV, it will be pretty darn accurate all the time. Now every still, thermometer, elevation, etc. it's different. So the ABV for my still at 92C won't be the same as somebody elses here at the forums. The best way to communicate via the forums if you want to talk about distillate strength is to use ABV rather then temperature.

Is temperature better then using a hydrometer to measure ABV of the output? I think that depends on the size of the still, if your pot still can have a thermometer placed correctly, and other factors such as the temperature of your distillate output.

For example, if you have a worm a thermometer location might be difficult to place. Or if you place the thermometer somewhere in the lyne arm where not all the vapors are going to go through the condenser - in other words the thermometer placed in where some of the vapors might condense and go back in the pot. Then using a hydrometer would be better - of course you need to make sure you temperature correct the reading based on the distillate temperature your measuring.

However, if you have a small still like mine (2.5 gallon) and a liebig condenser. A temperature probe just right before the condenser will give an accurate reading of ABV output. And it's more convenient than collecting a ~200ml sample and using a hydrometer and then using a hydrometer temperature adjustment chart. For me, by the time I'm done doing all of that I end up with the same answer as just glancing at the temperature.

I don't have a turn signal on my still, but I got a thermometer

That's my 2 cents.

GingerBreadMan wrote:The only thing I'll disagree with, is the idea that temperature and ABV output are not the same...

... if you have a small still like mine (2.5 gallon) and a liebig condenser. A temperature probe just right before the condenser will give an accurate reading of ABV output. And it's more convenient than collecting a ~200ml sample and using a hydrometer and then using a hydrometer temperature adjustment chart. For me, by the time I'm done doing all of that I end up with the same answer as just glancing at the temperature.

Temp and ABV are directly related in a perfect world. Most of the folks here are not gonna have the sort of sucess yer havin' linkin' the two. It sounds like it workin' perfect for you... can ya make cuts usin' yer thermometer alone?

I'm not criticisin' any of yall. I'm just suggestin' that the new folk, readin' here in the Novice Section, will probably have better luck with a hydrometer. I have no problem that some of yall disagree with me, please do the same.

For you new distillers as you can see many different ideas try them all and see what works for you. do not be stuck on one way. what works for me
mite not work for you.

"can ya make cuts usin' yer thermometer alone?"

I suppose I could if I wanted to. But I don't. I don't make cuts measuring with a hydrometer either.

THM, I don't see anybody saying that cuts should be made using a thermometer, just that it is a useful input for monitoring what is happening inside the still.

Yes the temp is going to vary a bit between different still, different washes, different weather, etc, but not so much that temp is completely useless. In fact those small differences can be quite useful info themselves, teaching people about the slightly different ways a still behaves under different conditions.

This is a science based practice we are talking about, temp changes are not arbitrary, the rules of thermodynamics don't alter between runs, it is repeatable. I find the temp behaviour of my pot still generally quite consistent, and the small variations in that pattern tell me something. For example, if the initial temp point it settles at straight after boil up is relatively high, that tells me either that the wash has a low %abv (if it is low wines run), or I am running too hard (if it is a spirit run).

I don't see anything wrong with newbies using temp as an additional, secondary bit of info in helping them to know what is going on during a run. Learning all the aspects of still behaviour can only be a good thing. I use the sound of the still running as one quite useful bit of info about what is happening, but I don't use to determine where I make cuts, that can ultimately only be done with smell and taste.

I think everybody agrees that cuts should be made with smell and taste.

I personally like having it while I didn't want to install it I now find it helpful or useful as I am just now getting to the point where I think I can take the training wheels off my still. For instance, I just did a fruit wash for the first time and the temps did run different from the grain washes as well as the alcohol content through the run. Just so happens that the time the tails were beginning to come through so was the beautiful aroma and filled my shop with the smell of slightly overripe plums. I had however missed my cut point being overwhelmed with the aroma. When I looked at the temp it was up to 203* and at that point I had began getting the wet cardboard smell. Knowing the normal temp for tails on my still is 202* i was able to back up a couple jars and pick out the tails immediately after smelling the know tainted jar even through the aroma of the plums. It just helps me and I thought I would pass that along to someone else who may be having trouble or about to have some trouble in the future. Just my little minute contribution for all I've gotten from this site and you good folks. Maybe it'll save someone a newb question later on.

yes thermometers /hydrometers are good guides just like baking a cake recipe calls for 30min in 350 oven at 25min you'd better git out the
tooth pick then watch until is done. If you did the same thing all the time mite be different. but I do not ,not anymore and every stove different
every still is different every wash/mash is different . so use as a guide not fact

Well put Dnder.
I think that most people have agreed on here that
1) Thermometers can be handy for indicating changes going on within the still.
2) Hydrometers can also give you the same indications. as can rattles, squeeks, rumbles, sighs etc. etc. etc.
3) None of these alone should be used to make your cuts.
4) Smell, Taste, Feel will always be the deciding factor.
but,
5) anything that helps a newby get started along the right track is OK by me.

Cheers.

On my old 13 gallon copper pot I always used a thermometer. It was a dial with 6’ of line and a probe on the end, old commercial dish washer thermometer I think it was. Had a screw in fitting so I could flour paste it up on the cap. I’d set it right down in the mash before sealing the lid on. It would let me know when to cut back the high propane flame to a nice low running flame. Didn’t really matter if it was calibrated correctly or not, heck it could have been 10 degrees off and it wouldn’t have mattered! I just knew that when it got to a certain temp, cut the flame back, it would rise another 10 degrees or so and that’d be the starting temp of 201 F. And that 201 could have really been 180 and it wouldn’t have mattered it was a random starting point for my particular setup. You’d want the temp to slooooowly climb and the thermometer would let you know if you were running too fast or not. By the time the mash reached 210 you knew the end was near or already passed. Again that could have actually been 185 or 211 and it wouldn’t have mattered, it was just a guideline to let you know how it was going

Now it wasn’t always right at that temp it would start or end but it was a general place to begin. Mash strength, weather, kind of mash and all would alter the starting temp some, as others have pointed out. Bring it up to temp, give the pot a listen and feel the cap and condenser coil. Is it happy, can you hear the happy gurgling or are things too quiet? If it wasn’t quite ready tap the flame up for a bit. Maybe ABV of the mash was low or there is a big storm coming. Never used it for cuts, as pointed out before, that’s what taste and smell are for. I recall a couple times that she started working well before 201 too! Before temp was reached the cap and coils were hot and it was working hard. Those were batches with over 10 gallons of mash (my standard mash volume) and higher than average ABV content. After a number of runs you could tell by dipping a finger in about what to expect starting temp to be.

Could I have used it for cuts if the thermometer was in a different place? Naw, don’t think so. Even running the exact same recipe time and time again there is going to be some variation in it. Sometimes you got a gallon, gallon and a quarter, gallon and a half, two gallons. For me and my Pennsyltucky drafty stone basement operation when it stooped tasting right, it was time to stop regardless of how much had been collected or what the temp was.

At the beginning of this thread I said to my self "i better open up my 'notes' page and start cutting and pasting". Then i kept reading and started to get confused. read some more and started to get a little angry. then i got thirsty and got a beer. came back and read some more and started to feel better about the whole thing and forgot all about cutting and pasting.

Now that its all straightened out and no one has had to go for stitches, its time for another beer. But really, i do appreciate all the time honered experience and willingness to share. Just had to give some one a laugh.

I learned best by doing my first runs in a pot still without a thermometer, using only my senses, then using a thermometer on later runs to ensure that the temperatures were consistent with my senses. That's what I would recommend.

I wouldn't spend much time with the thermometers on a pot still.Time be much better spent smelling tasting and feeling.Just my 2 cents.