Analysis of Cuts from 2nd Run

[Koula]

Looking for some experienced eyes to scrutinize these results. Below is my data from a second distillation of 3 batches in a flow management reflux still (Kegomax FM). Foreshots (250mL) from each of the 3 first batches were discarded including the foreshots from the second distillation (150mL). I'm confused as to why the results are of such low % despite manufacturers claims that this still can obtain 96%. I'll explain a little more about my procedures, please pick them apart and suggest areas of improvement.

The first batch when distilled, yielded 4L at 92%. The temp range was between 76.7C and 77.1C.
Second batch resulted in a mere 73% and lower and ranged between 85.6C and up... terrible results.
Third batch yielded 1150ml at 93% 76.6 and 77.1C, and 86% between 77.1C and 88.8C. Further cuts were 62, 52, 39, and 25 %.

I tossed the above (18L) back in a HDPE barrell, measurered ABV which was 68%. Used HD calculator and diluted to 40% and added 250g of fine carbon.

Question: In the best results above (92 and 92%), what makes up the remaining 7-8% of solution? Obviously not any water as the wash never reaches boiling.

30L @ 40%
Start Temp 76.5
Vessel # - mL - ABV - Max Temp C
F - 150 - -
1 - 1000 - 91 - 76.7
2 - 700 - 90 - 81.3
3 - 1150 - 83 - 78.9
4 - 1000 - 84 - 78.9
5 - 1000 - 83 - 79.5
6 - 1100 - 83 - 78.9
7 - 1000 - 83 - 79
8 - 1000 - 82 - 79.3
9 - 1000 - 81 - 81.5
10 - 950 - 77 - ?
11 - 500 - 74 - 86.2
12 - 600 - 70 - 87.2
13 - 630 - 67 - 88.3
14 - 600 - 64 - 89.3
15 - 1000 - 56 - 91.7
16 - 1080 - 45 - 94
17 - 1000 - 30 - 96.4
18 - 2000 - 7 - 98
TIME: ~7 hours, initial average 15min/L.

So I hope you can see that I was a little disappointed to be distilling 12L or pure alcohol and not even receiving 2L at 91%, a far cry from the 95% I desire. Did the distillate come out too fast? I aimed for a pencil drip, and visibly observing the distillate pooling in the outlet funnel and pouring back into the column. Should the distillate be pooling as high as the condenser? The stainless steel packing is also pushed so high that it wraps around the outlet funnel. The thermometer is therefore in the packing, not in free vapor. Could the packing, contacting the outlet funnel, be reducing purity? Or is this just a question of the outflow was too fast, a drip/pencil stream?

I plan to re-dilute to 40% and run the still again, this time aiming for 60min/1L (yes, this will be painful). If there is another solution, please let me know! Thanks!

And finally...For the third distillation, do I again throw away the foreshots? (they're adding up now...)

[Usge]

Unfortunately Koula, it's quite common for people wanting to just jump in with both feet to get wet (ie., buying or building things) before they fully understand enough to know what to expect. I'l try and get you down the road here.

First, you might want to read the theory section of the main site. It fully explains the distillation cycles and theoretical plates...and answers the question as to why it takes more and more cycles/reflux to reach 96%. Getting to low 90s is generally doable on just about any column that has some type of compound/forced reflux. (ie., a coil, jacket or other reflux condenser system in the the top of the column). But, getting above that takes increasingly more effort. The main theory section of the website will answer your questions here and you'll have a better understanding. I would also recommend you check out the Compleat Distiller by Nixon& McCaw.

Now, as to your current situation....you have a CM (cooling management still). Member Prariepiss...has an excellent write up on how to get the most out of that type of still design. You can find the link to it in his sig and you should read it. You'll want to separate your cooling for the reflux condensor so it's "T"d or "Y'd from the input (cool water)...not running off the used/heated discharge from the product condenser. PP's post has instructions on options for plumbing your CM to make it more effective and have more control over the water cooling. You'll also want to make sure the column is properly packed.

Getting the balance of heat to reflux is important to achieve the highest purity levels. There are lots of ways to setup your parameters for a CM...but Manu gave me advice one time on adjusting /setting up a CM that I always found helpful. Bring it up to a boil till it starts to flow...then turn your CM water/reflux on full. By that I mean...using as much water as you can...or...care to for what you would consider to be your "max" level (ie., knocking everything down). Adjust the heat till you have just a drip coming out. Now...back off the heat till it just stops dripping. Make note of both how much water flow you are using...and what the water temp is (going in). And what power level you are at. And next time...once she starts dripping...you can just set both of those. That's your max reflux level. This is dependent upon the still charge (alc volume). If you are running lower proof/wash/mash...then the boiling temp will be higher and the cooling/heat may need to be adjusted.

From there...you let it sit under full reflux (nothing coming out) for 45 mins to an hour. As everything is being returned back down your column through the packing, this will help "equalize" the column and stack the fores/heads up in the top of the column. Then you want to start dripping it off at a low enough rate to maintain your max reflux. Now you can do this one of two ways.....by reducing the water flow to your reflux condesnor (which will allow more to pass). Or..by "increasing" the heat level. Some people prefer one method over another. But, I would say it depends on what your initial water flow vs heat is. If you start with your heat level high, probably reducing the water flow may work better. If you start with a lower power level (have plenty of head room) ...then just pushing the temp up (or using "power management")...will give you quicker results...and more reflux...given you aren't reducing your reflux cooling..but just sending more vapor up to it. That works well up and to the point that it smears and/or floods the column (you'll hear gurgling). With everything "squeezed"....you set your takeoff rate only to that which will maintain the proof you want. If you are dropping proof..you don't have enough reflux and/or need a higher reflux ratio. That inherently means you either reduce your take off rate...(usually to a steady drip)...and/or rebalancing heat/cooling or both. You can also put it back into full reflux (nothing coming out) and let it re-equalize for another 30 mins or so...to bring the proof back up if things get out of whack. As the vapor temp rises through the run...and the reflux cooling temp remains the same...it will "squeeze" everything out up to the point that it just nearly stops dripping. Your at tails at that point. You can re-equalize as many times as you want to try and squeeze a bit more...but you'll know you did it right when you turn the reflux off and just flush out remaining tails and you only get a small amount.

So, it's a balance..between how much heat you have (vapor going up) and how much reflux cooling you have (reflux going down)....vs how much distillate you take off. Inherently...if you understand all this...understand "why" your runs are going to be 8, 10, 12, hours. I've had some longer. Just depends on what you are starting with in the pot...and a pot full of low wines...makes getting to 96% a bit closer...but...also means there's a lot of alc to drip off. The advantage of these type stills are that they are entirely flexible. You can run them with as llittle or as much reflux as you care to. And once you get your cooling/reflux water so it's running from a consistently cool source...it means that as the proof drops naturally in the course of a run (ie., the vapor temps rise)...the same temp/cool water is applying more and more reflux to it...squeezing it as it goes. If you run the water off the product condenser...then the temp of the reflux water will increase slightly through the run...which is counter productive.

Now...lastly, it's not as bad as it sounds. Even if you end up having to run less alc volume to start...so you aren't up for 2 days straight....at 96% (or close to it)...it waters down quite a bit to get to 80-100 proof...which will give you some volume back. With higher reflux ratios...you'll get back more body/hearts as well....particularly if you equalize the column first by letting it sit under full reflux for an hour. As far a then filtering it with activated carbon...I believe the best way is to drip it through a tube filled with the carbon...with a filter on the end. Getting that stuff filtered out is hard if you just dump it in and let it sit. They sell...filtering setups...but easy enough to make one with a stainless tube (or copper for that matter) and put a couple coffee filters over the end. You can take a look at some of the commercial designs to get some ideas.

As to fores...I always toss a bit no matter how many or few runs. Your nose will probably tell you same.

Anyway...this should help at least get you in the ball park. Don't skimp on the reading/study. It's very important to understanding whats going on. And do check out PP's link on getting the most out of these CM stills. Good luck!

http://homedistiller.org/forum/viewtopi ... 17&t=25732

[Prairiepiss]

Good writeup Usge.
Link to cm mods in my signature.

[Koula]

Hi Usage,

I appreciate your offering of time to reply in great detail. I fear I may have not been clear enough when indicating which type of still I am using. Unfortunately it is not a CM still. It only has one condenser and is supposedly a "Flow Management" (FM) still, whereupon purity is supposed to be controlled merely by the Hoffman clamp on the product output and not by the temperature or volume of coolant liquid. From everything you've mentioned as well as other reading, I am skeptical that coolant temperature would not have an effect on the amount of reflux occurring. I just realized that the first batch which obtained the best results was on bore water, whereas all subsequent batches have been using pool water (~18C).

As the still is glass I can observe the reflux occurring and control the Hoffman clamp to increase or decrease the "pooling" level around the condenser. I now realize that 100% reflux for 1 hour to equalize, and periodic equalization is important. As the output fluid is quite hot, I can't think of a way to monitor it's purity without rigging up a separate collection vessel cooling method. Any tips here?

Another mistake to note with the 2nd distillation above was that there was almost no head room in the boiler, maybe 3cm.

I read PP's CM post regardless, thanks for the reference.

If a batch is taking a long time, say 12 hours, is there any danger in shutting it down and resuming the following day? (assuming the remaining liquid is still at least 20%ABV) Or is it better to run smaller batches fully?

Thanks again!

[rad14701]

What you would be referring to is Liquid Management... There is no Flow Management... Cooling Management, Vapor Management, Liquid Management... There is also a Power Management but it is rarely discussed...

If you haven't done so already, please post pictures of your equipment so we can insure that what you are using is safe... Glass is not recommended although several members do run glass in light of the fact that it can have catastrophic failures... I'd also be concerned about your clamping of a synthetic hose for control... Please see Rule #8 of The Rules We Live By...

[Prairiepiss]

I finally found a pic of this thing. Is a LM still. Obviously the fact that everyone has removed them from their catalogs. Mite say something about them.

[Koula]

I'll post some real pics in the future. For now this is from the product brochure (pdf too large to attach). Kee from KegKing had suggested that this unit was actually better than his CM model, but that the profit margin compared to other major brands was too little to win over the retailers. Anyways, here is the cropped picture from the brochure.

He most definitely said there is no requirement to modulate coolant flow with this design but rather that the hoffman clamp (on a silicone hose) is all that is necessary to control output flow and therefore purity (in his theory). He sounded like a knowledgeable bloke and honest enough as well, when the copper condenser I received had crooked brass compression fittings and was leaking, he sent me a replacement asap. But admittedly his expertise is for brewing and importing equipment. Curious to hear further thoughts.

[Usge]

I used the reference for the name you gave and downloaded a brochure which showed a CM model. Sorry for the confusion. Yes, it appears to be a LM (Liquid management) still. Other than the control over the reflux condenser water flow...everything I posted above is still pertinent to this design.

Reflux ratio: the amount of vapor returned back down the tube/column, vs the amount of distillate you take off. The more that it returned down the column...the higher your reflux ratio. That conversely means as I explained above...your take off rate is going to be slower.

Everything I said about equalizing the column, etc..is all still the same. So, it is for set up as well. You set the condenser to knock everything that comes up down. And you leave it that way for 40mins to an hour. Your vapor temp reading should be somewhere close to 173F. (assuming your therm is accurate). It might even be slightly below that. As you drip it off...slowly...it may rise a bit until it settles (this is getting the lower boiling point volatiles (ie., fores) off. Just keep dripping it off slowly to maintain highest purity. If you take it off too fast...the temp will start to rise and the proof will drop. If either of those things happens...shut the valve so nothing comes out...and let re-equalize. Then drip it off again slower.

It's exactly the same in terms of balance between heat/cooling and take off rate. Teh more heat you run..the more vapor it sends up the more reflux there will be the higher you can push your reflux ratio. So, if you find you have to constantly rebalance your output flow to keep the proof from dropping even when dripping off the run...then you might not be pushing enough heat. Your take off rate will be slow. And the diagnosis of your problem here would be the same.....you were running too fast a take off rate to maintain higher reflux ratio for the given amount of heat you were using. Your instincts are correct....slow it down. Take it off slow.

Once you get yoru column equalized with the coolest (lowest boiling point/highest proof) vapor at that tiny little pocket at the top where your therm is....you should have a temp gradient inside your column. If you push too hard...you mash it together and smear everything...ie., pushing warmer and warmer higher temp (lower proof) volatiles up the tube. If you don't have enough heat...there isn't enough going back down the column...to maintain this gradient when you start pulling distillate off and it collapses. The best example I heard was in Nixon's book...where he said maintaining that pocket of highest purity...was like a man walking on a tight rope with a sack of potatoes on each end of the balancing pole. If you take one potato at a time here and there....he can adjust and maintain balance. (equillibrium). But if you snatch a whole arm load off one side or other...it can quickly unbalance things.

So, the point is..to reach your highest level of reflux (reflux ratio) and maintain it by only drawing distillate off as fast as you can maintain temp/proof. And in this design (LM) your valve is like a rheostat for proof. The more you close it (reducing take off rate) the more the proof will rise. The faster you take off product...the more the proof will drop. That's why they call it "liquid" management.

There are also instructions for operating an LM written by Husker that will get you up and running. There are many different designs for LM stills (ie., Nixon-stone, Boka, etc). They all operate basically under the same principals.
Try this link and see if it helps: http://homedistiller.org/forum/viewtopi ... 63&t=13265

[Koula]

Hi Usge, everything makes a lot more sense now, good descriptions, thanks. I hadn't considered the speed of "take off" being a variable, nor 100% reflux time. Of course temp will rise and fall with increased output, but that didn't click for me before. Now my results make more sense. I also did not have the head room in the boiler to create sufficient vapor volume, and perhaps the boiler was struggling since it was so full. I'm curious about one of your points:

if you find you have to constantly re-balance your output flow to keep the proof from dropping

This suggests that you have a method to actively determine proof quality on the spot? Is this right? If so, how? I had thought about wrapping an ice pack around a measuring cylinder to cool the liquid to 20 or 25C. My alcometer (still spirits) is calibrated to 20C. I do wonder if it's accurate. Olfactory and touch senses to determine quality don't make any sense to me, unless I intend to gather 10'000 hours of experience to qualify as an expert, which I will never do.

Thanks for the explanation of liquid management, again you provided for another 'ahah' moment. I've read the differences before but it never sinks in the first time. So KegKing is just trying apply a brand name to an established still type. That is, they're trying to re-brand LM as FM with this particular still.

I do like the analogy you granted, and I'll be super aware now of maintaining the vapor pocket. I find it very interesting, using a glass still, to observe the reflux occurring and how such subtle turns of the Hoffman clamp instantly increases/decreases the pooling effect around the output funnel. I'm curious to see during equalization if the liquid pooling will go as high as the condenser.

I'll keep you posted when I perform the third run. Cheers!

[Prairiepiss]

So KegKing is just trying apply a brand name to an established still type. That is, they're trying to re-brand LM as FM with this particular still.

Yes. What does that tell you about them?

[Usge]

This suggests that you have a method to actively determine proof quality on the spot? Is this right? If so, how?

Not exactly. You want to monitor "temp" changes at the vapor pocket. That is the current temp/proof of your take off point. If that temp goes up...your proof will drop. If that temp goes down..the proof is getting higher. This is all based on boiling point (theory from the reading material I gave you to reference). In a "mixture" of mostly water and ethanol (boiling points of each are 212F water, 173 ethanol)...the higher the boiling point...the more water there is, the lower the proof. The lower the boiling point, more ethanol, the higher the proof. So, what you are monitoring in that little "pocket" is the "vapor" temp...at the highest point right right at the take off point where you will bleed off the distillate. And yes...that will consistently tell you where you are at proof wise (allowing for any offsets, for therm, etc). Map it yourself. At x degree...I have x proof coming off. It will happen the same way everytime. So, when you see "that" temp...you'll know you are about to get "that" proof.

This is your most crucial feedback for this type of still. When that temp is going up...you are losing proof. When that temp goes down...you are gaining proof. So, what you are looking for to achieve what you want...is the lowest temp you can stablize as close to 173F as you can get (recognizing that your therm may be off by a degree or two). And to hold that temp as long as you can. As I said before...because there are foreshots (volatiles with lower boiling point than ethanol) you "may" see the very beggining of your run after you stabilize and equalize it...and start dripping off fores...temp rise slightly..then stabilize a degree or so higher. You may see this happen, you may not. But, after fores ...whatever temp it's stuck at...you monitor that. And you can increase your drip rate for your take off...until the point that you see that temp start to inch up. Then...shut the valve..let it stabilize back down again....and reduce your take off rate until you've got one you can maintain. (it's gonna be slow...like 1-3 drips per second max).

Now...you monitor your temp... and if you see it rise up...shut the valve...and let it stabilize back down ....then start again..even slower than before. You keep doing this...until even after closing the valve and restabilizing...you can't hold proof/temp anymore when you start to drip it off....or nothing comes out until you open the valve way up past where you can hold/maintain temp. Then you are at tails. At that point...you just open the valve wide open and flush the rest out....(or just shut everythign down and toss out the tails with what's left in the pot). You'll want to measure it though the first few times (volume). Because it will give you a clue as to how you are doing. If you did it right...you should have very small volume of heads and tails...because you "stacked" or concentrated the heads up front and pulled them off slow....and you "squeezed" the end of the run to get all the ethanol you could leaving only the worst of the tails. This is why some people "don't" recycle head/tails from runs on a still like this (they are really nasty and heavily extracted)....unlike postill runs where the heads and tails are bled across more volume of ethanol fading as they go. If you ended up with lots of heads and/or tails...then it tells you that you didn't do something right at the front and/or back of the run. You'll see when you run it.


As far as monitoring the proof of spirits coming out It's called a "parrot". You can ultimately judge the accuracy between your vapor temp readings...vs the proof of the distillate you have coming out given the direct correlation (again...the theory reading section) between vapor temp and proof of the corresponding condensed vapor (ie,. distillate).

You can do a search for it...there are plenty of examples and pics around. It's basically a tube that your output drips into with an overflow and spout...that you float your alchometer in..that will give you a constant readout of proof as your run progresses. You can adjust for any heat/calibration differences using a reference chart. But, if your distillate is constantly coming out warm...which is common with this design...you can build some sort of condenser to help cool it before it reaches the parrot. Or what I do is just take about a 1 gal bucket and fill it partially with cool water and put the parrot in it so the spout hangs over the edge. The water surrounds the tube of the parrot and seems to keep it much closer to temp. Don't think you'll want or need ice with that. That would probably take it too far the other way. Because the parrot holds a modest sample size (ie., 100-200ml) it's always going to be a bit of a mix. Just watch the head temp. That's the key to operation of these stills.

[rad14701]

Koula, you should be very grateful that Usage has gone to such extreme efforts to provide such detailed explanations because we generally don't spoon feed and this is all information that you would generally glean during what we consider mandatory independent research here in these forums and on the parent site... Perhaps it's time to up your efforts towards becoming better versed before proceeding much further... I can assure you that you'll have many "Ah Hah!" moments and the connections will start forming in the gray matter... And you'll even learn answers to questions you don't even know you have yet...

I can't say that I'm thrilled with your current choice of reflux column in the least and I'd strongly urge you to start planning on a replacement ASAP... I'd take safety over wow factor every time...

[Koula]

Rad, no worries there, this is definitely just a cheap-o get my hands dirty kind of still. I believe in studying theory to an extent, but also getting your hands dirty eventually. That's where this site is great, through offering feedback Usge has no doubt sharpened his/her own knowledge. Now, back to the textbook before any future runs.

Letting the still equalize for an hour was gold advice. Where previously the temp was all over the place, there was zero fluctuation with my last run. Yield is 9L at 93%. The still ran at 76.3C and ended at 76.5 abruptly. The last 400mL shot up to 78.5 and I shut down. I do wish it was capable of obtaining higher proof, however at nearly 2 hours per liter I think 93% is satisfactory.

[Usge]

Sounds like a good improvement. You might try bumping up your heat just a touch, and letting it equalize a few mins more. More heat will give you more vapor, which if you take off at the same rate as before...should give you slightly higher reflux ratio.