Why I'm Tired of the CM Hating

[Kifi]

If you're new to distilling and you're planning on making Vodka or some other neutral spirit, one of the first pieces of advice you'll get is to build a VM or Bokabob, and to stay the heck away from CM. Today I'm delivering a fiercely partisan rant in favour of our unloved friend, the CM still.

For those of you newbies, CM, or cooling management stills, use the rate of coolant flow in a secondary, column mounted reflux cooler to regulate purity. The faster the coolant flow, the higher the reflux/purity and correspondingly, the lower the rate of output. Mile Hi, Brewhaus and Coppermoonshine stills are all mostly CM stills, if you want to see some for yourself.

The haters complain of the difficulty in keeping coolant flow regulated with precision. For this reason, CM is to some the 'pervy uncle' of the three major column still types.

Here's what I have to say about a) CM and b) some of the most popular CM designs.

1. Get a Mile Hi still and it will work right out of the box. The gate valve on your garden hose tap will give you all the resolution you need to regulate purity and output. Invest in some 2" pipe insultation and it will work even better. And you'll be hard pressed to get anything less than 92.5%. Just crank the water until it comes out of your hose lukewarm, and the distillate flow stops. Leave it for 90 mins, then slowly turn the tap back until you get a couple of drops a sec.
2. This still will be indestructable. You can use it and abuse it, unlike the all copper PDA 1 which has to be handled with discipline and care, all the time.
3. Cleaning? Easy. Disinfecting? Easy. Tarnish? Never.
4. They're cheap. The PDA 1 column alone will cost you more than the entire still.
5. The column is the perfect length to also be a very good pot still.
6. VMs have their own challenges - like you can blow them up if your heat input overwhelms your cooler during equilibriation and you don't have a safety valve built in. Or implode the column if you forget to open it at the end of the run when you turn the heat off.
7. LMs undergo a decreasing reflux ratio during the course of the run, unlike CMs.
8. The guys who complain about CM are really smart guys who build expert level stills. It's like the guy who builds a Ferrari, then complains that his toothbrush isn't electric enough.

Happy USA/Canada Day Weekend, Everyone!

Kifi

[hackware]

sumtimes, life is just too funny...

[mash rookie]

My first still was a CM. Worked pretty good. My new flute is a CM. I love it!

No reason to hate any design. Opinions do run strong around here though.


Have a safe and fun weekend all !

MR

[Kifi]

My first still was a CM. Worked pretty good. My new flute is a CM. I love it!

No reason to hate any design. Opinions do run strong around here though.


Have a safe and fun weekend all !

MR

So how cool are the windows and the bubble plates? Better than watching fish in tank, I'll bet....

[Coaster]

.....6. VMs have their own challenges - like you can blow them up if your heat input overwhelms your cooler during equilibriation and you don't have a safety valve built in. Or implode the column if you forget to open it at the end of the run when you turn the heat off...Kifi

@ Kifi,

All the Vapor Management (VM) stills I have ever seen have a reflux condenser in addition to the VM product condenser. If the reflux condenser in a VM still is manufactured correctly it has an atmospheric vent. The atmospheric vent in the VM reflux condenser will prevent over pressurization of the boiler and/or the column exploding and will also prevent the boiler and/or the column from imploding.

Regards,
Coaster

[Kifi]

Very good point. I have a valve in my VM in lieu, but going to drill a hole in the top of the reflux condenser for good measure. Wonder what percentage of VMs have safety features?

[LWTCS]

I figger the beef is really about where the cooling is oriented.....

Nuthin wrong with cm as long as the cooling is as high as you can get it..... Is it as good as a VM or LM.......? Dunno. But my CM can pull 95 with a tooth pic stream....

Is it neutral? God I hope not.

[theholymackerel]

Lol!

Kifi, I will defend yer right to yer opinion to the end, but I suspect yer opinion is based on emotion rather than experience. (I'm sure ya got plenty experience with CM, but do ya have as much [or any] with the other types of reflux stills?)

This reminds me of an old neighbor of mine who used to talk about how superior his 66 dodge 1/4 ton was to my 2000 ford 1/4 ton sport truck. I pointed out to him that i got almost twice the gas milage. He insisted that his truck rode better. I demonstrated that mine handled better loaded, or empty. He switched to acceleration... but after my truck smoked his (with almost twice the MPG, don't forget) AND stopped in less distance, all he could do was say how the bug-eyed monster he drove looked better and was safer (lol). I pointed out he had only lapbelts while I had more comfortable and safer belts, airbags, and ABS.

None of it mattered... in his head that ugly old inefficient and slow truck was WAY better.

[Kifi]

HolyMac - read my footer - I got one of each and use them all. But a post based on emotion - some would say 'passon'? Definitely. And I never said which one - LM, VM or CM - was the best, or my fav. But one is getting dumped on unfairly. I'm just sticking up for the little guy. Someone has to do it.

[Usge]

Much of the CM hating (although I don't know that this is exactly how I would describe it) was based on an older design where the reflux/cooling tubes went through the bottom and the top of the column. This was counter productive and not nearly as efficient as the "new" designs they are selling today...where the reflux portion has been properly isolated to the top of the head so that it can return distillate to the column. I think the other part/side of those objections were as to the strong emphasis on "Turbo" washes, etc. There have long been properly made CM designs around here...that worked well for people, and they also can be made cheaply. They aren't even that hard to make. But, I believe if you'll look, you'll see more recommendations for those stills today, than was the case in the past (previous design).

There is no question the newer designs from milehi, or brewhaus for that matter, are a good value for someone looking to buy into this. Heck, I even know one "distillery" using them. And it's always been true that a CM design can run with the cooling "off" as a "true" potstill...as well which makes them even greater value. I would just mention there have been people for many years around here putting coils, or cold fingers up in the head of potstills and getting good results with them. Taste being subjective of course. They have always worked well. The design using tubes through the column (and worse yet..with it tied to the liebig), ...not so much.

So, I'm not disagreeing with you at all that CM stills can be effective, and flexible and good value to boot! They always have been. It was the particular design with tubes top and bottom that caused most of the angst over them around here. As to the PDA 1 head...I haven't used one, so leave that for you and/or others who have.

[Kifi]

I hadn't considered that part about the CM base cooling or cross tube designs, Usge - wisdom and historical perspective. I like it!

[mash rookie]

My first design was the still with the tubes through the column only I did not put the tubes through but alongside and insulated the column. The only reflux it actually did was because of the height and copper packing. At best I got 85% on neutral. Did pretty damn good as a one run and done for whiskey though.

So how cool are the windows and the bubble plates? Better than watching fish in tank, I'll bet....

Kifi it is so F...ing cool to run !!!

[LWTCS]

Yeah how you liking that MR?

Is she stable?

[Odin]

Hi guys! Love to hear someone make a positive statement on CM. I have one. Yeah, one with a tube at 1/3 and nearer to the top. Supposed to be crappy? Not in terms of results! 96% without a problem, great tails compression, great foreshots & heads extraction. And with a 40 millimeter diameter and 100 centimeters tall, a 1,500 watt hotplate I produce up to 750 ml per hour. I think the solution to sub-standard CM operation lays in the column packing. An open packing does not work. A dense packing like marbles or lava stoneds does. Cold through tubing cools the packing and all the water is in that way stripped out of the gasses going up your column. I'd love to hear more CM success stories! Odin.

[likkerluvver]

Yeah, I must say that I've seen lots of negative comments about CM here from people who freely admit that they have never used one. Seen a few comments that turbos are the shits - again, the author freely admitting never to have used them. It amounts to plain prejudice. Many nay-sayers simply regurgitate their previous readings of criticisms of ancient CM designs - which are now unavailable - except from unscrupulous fleaBay con artists.

Is CM a decent system? I truly don't know - not having tested it side-by-side with VM, LM and all the permutations. BUT I can get +95% from my CM rig, and I'm quite pleased with it. Before too long I plan to build a 3" LM / VM combo - can't decide whether to use copper or the Russian-preferred (and Polish-preferred) stainless for neutral/vodka production (that's another story).

I welcome informed criticism. It is the only criticism worth noting.

BTW, turbos are Great for producing large volumes of high alcohol content wash for bottom-shelf (not quite) neutral. I worked with them extensively before progressing to "Tried & True" and all-grain recipes. I shall never buy another. My actual experience confirms their inferiority.

Putting the soap-box away now.

[Husker]

I have to admit, I have not used a CM, I am pretty much a pot stiller.

However, being a pot stiller, I see pot stills in most things I look at. I really think one thing many miss, is that the CM can be one hell of a decent pot still, if the column is decently insulated, and the coolant to the column can be shut off during the run without impacting the condenser cooling. It can be used to compress the hell out of the heads early on, compared to a true pot still, and then the column cooling can be turned off totally once you have finished the heads, and you have a pot still. The only requirement is that the lebig and the cooling in the column must be able to be controlled independently, and it works much better if the column is insulated (to stop the reflux).

There are not many still types that do this type of run. The CM and offset are 2 that are well suited to do it. The boka is not. The plates get cooled off by the condensed product, and thus, reflux, and the flavor washes out. The VM 'may' be able to be used in this manner. I am not sure. If you can totally close off the coolant water to the condenser above the column, and shut off any vapor escape out the top, then a VM should also be able to be used, but I do not think most of them can operate like this.

Used like this, you can get a larger body output on whiskies / rhums, etc.

I know this thread has up til now talked about how neutral a product you can get with a CM. I know this takes the thread on a little side detour, but it still shows the usefulness of the design.

H.

[mash rookie]

Husker,
My CM would put out a decent neutral when run as slow as possible. Not perfect but decent. The best performance for my CM was using it on UJSSM one run and done. With all the packing and some refluxing I was getting a nice 75- 80% that had great taste.


Yes, LWTCS I LOVE my new flute. I am still learning how to run it. It is stable when I leave it the hell alone and don’t fiddle with the controls. But how much fun would that be?

[blind drunk]

Well then, maybe I'll hang on to mine and even start using it as a CM. Don't believe the hype, eh?

Forgot to add

[LWTCS]

Husker. What you describe is what i do with my tuneable thumper configuration pretty frequently here lately.
The CM tool does a nice job of mitigating or at least greatly reducing the potential smear.

[myles]

CM has its advantages and disadvantages. IMO it is one of the best systems available for heads concentration, but it needs constant attention if you try to use it for the entire run.

I used to use this.


The second condenser was connected to the air vent on the reflux condenser. I would stabilise the column and then reduce the coolant flow enough for the heads to get passed the reflux condenser. After which they would meet their own liebig. A variation on CM which worked just fine.

However I then switched to VM for the hearts phase.

I truly believe that you can get exceptional performance by using a combination of different reflux management techniques at different stages in the run. You can of course do an enire run on CM but it is hard work.

[mash rookie]

Myles,

That is an interesting still design. When you ran it did the heads continue to come off in smaller amounts as you were starting to take off hearts?
Do you think if the wash was not changing that you could take off heads and hearts at the same time?
You know where I am going with this questioning. Do you remember the continuous still design I was playing with?

Sorry to get off topic Kifi

[blanikdog]

What a silly thread.

[likkerluvver]

What a silly thread.

What an irrelevant comment

[blanikdog]

The entire thread is irrelevant. Who in their right mind 'hates', least of all a still. If anyone makes a comment about a stilling matter and someone disagrees, it's immediately classified as hate. We only post an opinion here lately and it's classed as hate by the nay sayers. Mashrookie and Holy's post are right.

For crissake, hating a still design or implying that others in here do has to be the most irrelevant post I've ever seen in HD. Any wonder there are people dying needlessly in war all around the world over nothing but a different culture, religion, race, skin colour, or whatever when a topic is headed "Why I'm Tired of the CM Hating". Gawd, people are only advising the flaws in a particular design. Where's the hatred coming from????

I guess that I'm tired of people hating, but obviously that's just me.

This is a silly thread.

[mash rookie]

What a silly thread.

its simple BD. Sometimes we just want to talk about things. The only thing wrong with this thread is that maybe it should be moved to off topic.

I also have noted that CM rigs get a bad wrap. Heck, I like them. Hell, I love all designs. They all have a place here.

Have you seen the wild stuff that Myles builds? Is that cool?

This thread is nothing more than friendly banter among smart guys with different opinions.

Sometimes the value is in the opinion exchanges and what we learn about each other.
MR

[likkerluvver]

..... This thread is nothing more than friendly banter among smart guys with different opinions.....

MR

Well said Sir!

Nothing in this thread for anyone to get upset about.

[Kifi]

What a silly thread.

its simple BD. Sometimes we just want to talk about things. The only thing wrong with this thread is that maybe it should be moved to off topic.

I also have noted that CM rigs get a bad wrap. Heck, I like them. Hell, I love all designs. They all have a place here.

Have you seen the wild stuff that Myles builds? Is that cool?

This thread is nothing more than friendly banter among smart guys with different opinions.

Sometimes the value is in the opinion exchanges and what we learn about each other.
MR

Amen - well said.

[hackware]

if you put a valve on your VM still reflux condenser, is it now a CM...?

[dougyethanol]

if you put a valve on your VM still reflux condenser, is it now a CM...?

no

[Prairiepiss]

if you put a valve on your VM still reflux condenser, is it now a CM...?

Yes If you also add a product condenser to the atmosphere port above your reflux condenser. You otherwise would be letting the alcohol vapors escape out the atmosphere port when you adjust the coolant going to the reflux condenser with the valve you proposed. That would be a bad thing.