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March 25, 2014

Making Moonshine: Still Temperature

We recommend reading Making Moonshine - The Dummies' Guide prior to this article, as it provides a good overview of the topic of distillation. If you're already familiar with the basics, read on!

The Boiling Temperature of Ethanol

We get a lot of questions about distillation and temperature. If you've read anything about distilling you might have come across information stating that the boiling temperature of ethanol is 174 degrees Fahrenheit. However, this is only partially true. The boiling temperature of pure ethanol is 174 degrees F. The boiling temperature of ethanol in a wash, that is to say, ethanol mixed with water, is completely dependent on the ratio of ethanol to water. The more water there is in the solution, the higher the boiling temperature. 

If you measure liquid temperature while distilling, you may have noticed that liquid temp can often be much higher than 174 before a still starts producing. Again, the boiling temperature of a solution that is 100% ethanol is 174 degrees. However, if you have a solution that is 50% ethanol and 50% water, the boiling temperature will be significantly higher. In fact, in a 50/50 solution of ethanol and water, the boiling (liquid) temperature of ethanol will be about 180 degrees.

Should a Still Start Producing Alcohol At 174 Degrees Fahrenheit? 

One question we hear a lot is "Should I see alcohol coming out of my still once the temperature reaches 174 degrees F?" The answer to this question is "No, you should not." Why? As we mentioned, the boiling point of pure ethanol is 174 degrees F. Wash in a still is not pure ethanol. If it was, why would you be distilling it? A first run wash is generally never any stronger than 20% ethanol. The rest (80%) is water. More likely it's something like 10% alcohol (ethanol) and 90% water. 

A solution that is 10% ethanol and 90% water is going to have a boiling temperature of about 197 degrees Fahrenheit. Did you catch that? A wash that only has a starting alcohol of 10% ethanol won't boil anywhere near 174. The temp will have to be much higher than that before you see alcohol coming out of the still. If you don't know how to determine the alcohol % of your wash, read our How to Use a Hydrometer article, because it'll tell you how to do it.

To determine the exact temperature at which ethanol will start boiling in your wash, check out this chart (Source: Craft of Whiskey Distilling by the American Distilling Institute). It shows both the liquid boiling temp of ethanol based on the concentration of ethanol in your solution. For example, in a wash with a starting alcohol of 20%, ethanol won't begin to boil until liquid temp reaches 190 degrees F. Also, keep in mind, the data on the chart above only applies if you're distilling at sea level! As you move up in elevation, boiling temperature decreases.

 Ethanol Boiling Point Graph

Should a Still Maintain a Constant Temperature During Distillation?

Another question we hear is "should I keep my still temp exactly 174 F during a distillation run?" The answer to that is "no, absolutely not." Why? Well the answer has a lot to do with the chart above. For example, if you start with a strong wash that has a starting alcohol of 20%, you can expect that ethanol will begin to boil out of the solution once liquid temp reaches about 190 F. As you let your still run and you extract alcohol from the wash, the wash alcohol % drops accordingly. Lets say that half way through the run you've pulled half of the alcohol out of the wash and have reduced the wash to 10% abv. Well, at that point you can expect liquid temp to have increased to about 198 F. The bottom line is that as your still runs, the temp constantly increases. 

Where Should a Thermometer Be Installed on a Still?

We prefer to install a temperature probe in the boiler, at the very least. Always make sure you use a 100% copper adapter and a stainless steel thermometer. Adding secondary thermometer at the top of the column to measure vapor temperature is helpful too. I like having one in both locations as it makes the distilling a lot easier. The two thermometers read different temperatures during the run, but they are also measuring two different things. The boiler temperature is measuring the temperature of the liquid inside the still, while the vapor thermometer is measuring the temperature of the vapor inside the column.

Keep in mind that the temperature reading you get is highly dependent on where you are taking the reading. First of all, never use an infrared thermometer to try and measure still temp. You know, the laser pointer types. Don't use them. They aren't accurate. They measure surface temp of your still, not of the liquid or vapor inside. Also, if your still is polished and has a shiny surface, the signal could be bouncing off and giving you reading of ambient surfaces.

Should Vapor Temperature and Wash Temperature be the Same?

Vapor temp and wash temperature should be very different. Once vapor begins to form in the pot and it migrates up the column, the vapor temperature probe at the top of the column (if you have one installed there) will rise from ambient temperature to 175 in a matter of a minute. Hypothetically speakingm at this point the boiler thermometer may read something like 195 F (again, depending on your starting alcohol) and the vapor probe could read as low as 175 F. There will always be a big difference between the two temperatures (boiler and vapor) which is not a big deal.

How to Use Temperature During Distilling

Temperature is mostly helpful determining when to seal the still, to know when it's about to start producing, and to know when it's about done producing. As far as making good product goes, we still think the most reliable method is to adjust heat based on the amount of product coming out of the still. You're looking for steady, fast dripping, not a stream. Also, keep an eye on proof. If your proof is super low at the beginning of a run, you either have very low starting alcohol, or your running the still too hot. We use our parrot kit to constantly monitor the proof of the product coming out of the still.

We also like to make notes in our logbook so we can reference them then during the next batch. We make notes on taste, smell, temperature, how fast the still is producing, how it feels (is it oily or not), and when we make our cuts. This all helps when we try to repeat a batch that was outstanding... It also helps us figure out what we did wrong, if the batch wasn't up to our standards.

 

 

  • I don’t get it ive tried 2 different kind of copper stills one 10 gallon without thumper one 25 gallon with thumper ive tried every recipe on the web I got food grade barrels for ferment ive used dist yeast over the counter yeast whole corn cracked corn corn meal sweet feed I get very litte shine for the amount of mash 25 gallon of mash about one gallon of shine help please

    Posted by terry on November 23, 2016
  • To stephen Pearman: Your heat level should increase as your level of water to alcohol increases, but it should only vary by 20*. In a column still, the head of the column should read 173.1 to 174…

    Posted by SJester on October 30, 2016
  • i have batch reactor for used oils to refine them by further process like filtration etc…my question is that i want to raise my temperature above 400 c but due to weak pipelines and old infrastructure i am not able to do so. so what should be the ideal batch reactor. please help me out its very urgent.

    Posted by pranav arya on June 22, 2016
  • You don’t run a pot still based on temp period. You run it based on still output ,and controlled output with heat input. You want a broken to pencil lead sized stream. The best place for a thermometer is under the heel of your boot.
    Jb-t

    Posted by Jb-t on March 28, 2016
  • Thank you very much for the wealth of information, after reading you thread I increased my Temp.and product started running in less than a minute….. Thanks again,,,Dmo

    Posted by don on March 28, 2016
  • If I’m making 5gal of mash how do I know when the run is done and should I throw out the first 1/2 of a cup

    Posted by Fred on March 09, 2016
  • What should my Vape temperature be for a good run

    Posted by Allen on February 26, 2016
  • Recently my water stopped inn my still and the water temp went to 80 c for awhile does that have any affect on the wash or the alcohol coming out?

    Posted by John on February 17, 2016
  • After reading all the posts, there are a few of you who should stick to making Kool-aid, At least you cannot screw it up that bad. All the information was givin prior to the comments. If you didnt understand what was wrote, try rereading the information, or google the parts you dont understand. Making good drinkable shine requires common sense, time, and a grasp of basic distilling.
    Thanks the lord that some of you dont cook dope or make explosives.

    Posted by Shishas on December 12, 2015
  • I have a reflux with a thermometer at the top of the column and none in the pot. at what temperature is it safe to collect for consumption? If the vapor temp reaches 173 then I would guess that the pot temp would be considerably higher and unwanted acetones and other undesirables would have flashed off by this time …. correct? What should be the least vapor temp that one should consider safe to collect ?

    Posted by GWH on December 01, 2015
  • Found out something important the more heat the faster your run. Also the faster your run the lower your end product proof will be. I went from a 12 hour run time with my 16 gal keg to a 3 hour run time with a 20 gal electric water heater with a few modifications of course and a shot gun style worm inspired by popcorn Sutton. I went from 155 proof down to 90 proof. At least I don’t have to temper it anymore. I will do some work on the heat regulation and get back to you…..

    Posted by tjcools on September 07, 2015
  • Found out something important the more heat the faster your run. Also the faster your run the lower your end product proof will be. I went from a 12 hour run time with my 16 gal keg to a 3 hour run time with a 20 gal electric water heater with a few modifications of course and a shot gun style worm inspired by popcorn Sutton. I went from 155 proof down to 90 proof. At least I don’t have to temper it anymore. I will do some work on the heat regulation and get back to you…..

    Posted by tjcools on September 07, 2015
  • I have been using a 15gal keg with a 2" copper colum I use a remote reading cooking thermometer duct taped to the side of the keg at liquid level of course and insulated with foam tape. I heat with a 1500watt hot plate. It dose take a while to get up to temp abut 2 to 3 hours before it starts to produce. My Temps will stabilize around 188-191 and provide a steady drip for the first 2000ml. Then the temp starts to rise on the boiler to 195-198 and the drip slows. I test the drips by collecting some on a spoon and putting a flame to it. I stop collection when only half the liquid on the burns off. The rest is tails that I add to my next run.
    Hope this helps you out.

    Posted by tjcools on September 07, 2015
  • Just got my new setup running. I was trying to cut my run time down. Found out 1 important thing. The more heat the faster your run and the lower the end proof. I definitely cut my run time. (From 12hours down to 3hours) but my proof dropped from a average of 155 down to 90. Not a big deal because now don’t have to cut it down to a safe usable level. I guess a little bit more work is needed on regulating the heat in my boiler. More to follow………

    Posted by tjcools on September 07, 2015
  • I have been using a 15gal keg with a 2" copper colum I use a remote reading cooking thermometer duct taped to the side of the keg at liquid level of course and insulated with foam tape. I heat with a 1500watt hot plate. It dose take a while to get up to temp abut 2 to 3 hours before it starts to produce. My Temps will stabilize around 188-191 and provide a steady drip for the first 2000ml. Then the temp starts to rise on the boiler to 195-198 and the drip slows. I test the drips by collecting some on a spoon and putting a flame to it. I stop collection when only half the liquid on the burns off. The rest is tails that I add to my next run.
    Hope this helps you out.

    Posted by tjcools on September 05, 2015
  • I have a 15 gal stainless cooker how can I install a temp probe in cooker cooker is a used water softner tank 4 ft tall

    Posted by sam iam on July 27, 2015
  • I have a 10 gallon copper kettle. everytime I run a batch my first cort off of it is a hundred ten proof, every cort after that is 99,80, 70 ,60 what am I doing wrong??? please help a beginner…

    Posted by Stephen Pearman on June 28, 2015
  • My question is the same as the first. Same setup. What is the maximum temperature I should let the temperature get at the top of my column?

    Posted by Lonn McMartin on June 10, 2015
  • My still is made from a 16 Gal. beer keg, with a 2 ft. tall 2 in pipe. the thermeter is install in the top, what is the max temp. i should allow it to reach?

    Posted by K.P.Pleasants on April 15, 2015
  • What temperature should my 5 gallon still be at to distill the highest proof when using grain

    Posted by EDdie on March 07, 2015


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