Better Operation of a Brew Shop CM Still (novice guide)

[kiwistiller]

Kiwi's guide to the better operation of a brew shop CM still

1 Introduction
2 How they work
--a What is your packing?
3 Why a CM still is annoying & a simple mod to help
4 Getting good neutral without a carbon filter
--a The ferment
--b Stripping run
--c Spirit run
5 Other spirits

1 Introduction
So, the homebrew shop saw you coming and now you have a Still Spirits / Essencia / something similar 25l CM still that looks more or less like this one.

look familiar?

Expressstapcc.jpg (6.25 KiB) Viewed 83414 times

Don't despair, because while the still you have definitely isn't the best, you can still use it to make spirits the will beat the turbo's and essences that your brew shop is selling hands down. This guide will help you to learn how, and is aimed only at users of these particular cm stills, and is not really applicable to anything else such as the taller CM columns that are advocated in some parts. It is written for a user that doesn't know any more than the brew shop has told them, which is the sad case for many people in my country (I was one of them!). I'm not trying to promote a flawed design here, but rather help out folks that got excited and made an uneducated purchase. I will try to link all the jargon to the wiki entries and so on to help the novice reader. Enjoy!

2 How they work
The biggest thing to get your head around with those cm stills is how they work. here is a quick and rough explanation in my own words:

Reflux stills work by sending a portion of the vapour back down the column as reflux. a CM still does this by cooling the column, so that most of the vapor condenses, and then a little bit 'makes it past'. This portion that makes it past is generally the lower boiling point compounds like ethanol, and the heavier, higher boiling point stuff (water) will fall back down (more experienced people reading this will realize this is an extreme simplification). In a taller column the falling condensate would mingle with the rising vapours and so on, but the columns are simply too short on these stills, and the condensation tends to happen on the sides due to the water jacket design (as opposed to a cooling coil in the column). This is why you'll never get as pure results as a taller column like a VM or LM.

So, hopefully you sorta get how the cm is working from that.

If you are confused about the different types of reflux still, BW Redneck has a good explanation of VM/LM/CM here.

2 a - What is your packing?
The column of these stills is normally packed with something to assist the reflux condenser in knocking down vapour. If this is copper scrubbers, fantastic, skip the rest of this section. If this is marbles, stainless steel packing, rings, or (the worst I've seen) a single marble, you should seriously consider changing to copper scrubbers. Your brew shop will probably sell these, they provide much more surface area, and this helps boost the ABV in our spirit run (see later). Depending on where you are, you may be able to get something in the supermarkets as well, but be careful that the material is safe for use in stills. Do your research on this.

3 Why a CM still is annoying & a simple mod to help
Now the reason that CM's are such a pain to run and are generally regarded here as more effort than they're worth is that you cannot control the 'reflux ratio' (the amount collected vs amount returned) by any means except cooling water. This sucks, its really hard to get right, so you should do yourself a favour and get a valve on your cooling line that you can operate by your still. garden / household taps simply do not have enough fine control in the lower flowrates especially on spirit runs (water takes more energy to knock down than ethanol. More detail on spirit runs later). Make sure you put the valve on the INPUT side of the cooling system, or all those push on fittings will burst off under the pressure at high temperature, potentially covering you in very hot water.

If you are on a water supply that has a tendency to vary in pressure, you may have problems with pressure swings changing the coolant flow for you. I use city water with rock steady pressure, so it isn't a problem for me, but if you do strike this, Hawke has the following advice:

A simple RV, (Caravan) pressure limiter would work. These go inline on a garden hose and limit pressure to no more than 40psi, without limiting flow. http://www.campingworld.com/shopping/it ... ator/26191" onclick="window.open(this.href);return false;" rel="nofollow

4 Getting good neutral without a carbon filter
Now for all their disadvantages, if you've got one of these already, you might as well work with it (well that's my thinking anyway, some will disagree). They can still be a good start to this hobby and you will learn a lot running it.

4a The ferment
The first step to creating a good neutral with these stills is to address your ferments. As we can only get 90% with these units, that's an extra 5% of flavours getting through when compared with the taller columns, so a clean ferment is vital. I strongly suggest shying away from the 48 hour turbo yeasts and so on, they produce some awful tastes. The only 'turbo' I've found to be any good is Essencia Super 6, which is nice and clean with some fruity notes, although I put in less sugar than recommended to avoid stressing the yeast. If you are really into your turbos for whatever reason, I'll not judge but this thread will help you get better results from them. If you aren't too attached to your turbos, Birdwatcher's Sugar Wash and Wineo's plain ol sugar wash are excellent, easy alternatives that will produce cleaner results than turbos. Yeast will produce fewer off flavours if you don't stress them out, so keep the temperature well within their tolerance and stable (colder end of the spectrum is good, I generally keep my washes at 21*C) and don't start with a really high specific gravity by putting in too much sugar, 1.08 is a good target for a clean, fast ferment.

Another easy way to make better spirits is to let your wash settle out nicely after its been done. I know, patience is hard, but seriously... just rack off the wash (leaving all the crap behind) into something else and LEAVE it for a day or two at least. There are commercial clearing / fining agents, I prefer to use time, personally. Then rack again into the boiler. Easy, you've got a clean wash

4b Stripping Run
As you read this site / forum, you'll notice a lot of talk of stripping runs. This is a rough and fast distillation through a pot still, to cut down the volume for the subsequent Spirit Run, in which you need to take care with cuts and so on. This may sound like double the effort, but a stripping run requires minimal attention, leaving you free to do other things in your shed and so on, and then only one in four distillations requires attention. It works out as a net time gain for me, but it also helps to make the product cleaner and stronger (it's been distilled twice, yeah?). I have achieved my best results (by far) for neutral when doing stripping then spirit runs.

There is a lot of info around on stripping vs spirit runs (parent site), but basically you strip the settled wash with a pot still, reduce the volume, take everything down to about 10% abv. Store this until you have enough, then dilute the 'low wines' (stripped wash, no wiki entry on it sorry) to 40%, and put it back in the boiler. Its easier to judge how much you have if you dilute to 40% right after distillation, but then you need more storage, so up to you. This is the spirit run, and you want to reflux it (for neutrals anyway). This run will take a bit longer, and need attention, but you'll probably do three strips (Which you can just turn on and do other things, though I'm not condoning leaving a still unattended, I do other things around the shed) to each careful spirit run.

These CM stills can be detuned and run like a pot still for stripping. This is a really, really useful 'feature' because the little cm columns are short enough to be effectively run as a pot, unlike true reflux columns which generate a lot of reflux due to height alone.

To detune, rip out your packing (the scrubbers, marbles, or whatever is in the column), and change the hoses around so that water is still going to the condenser (the offset bit where the distillate comes out), but not to the reflux jacket on the column. remember to always put cold water in at the bottom of the condenser. So, now you have a pot still, a clear path from pot to condenser allowing for minimal reflux. I'd take a photo of the hose set up but I've gotten rid of my CM now... maybe someone else can add one?

4c Spirit run
The spirit run will take longer than the others, so make sure you've got enough time. My spirit runs took about 5 hours from memory.
First thing you need to do is put the packing back in the way you found it, and set the hoses back the way they were (water enters at the bottom of the condenser, then goes from the condenser to the bottom of the reflux jacket, and then to waste). When you start the spirit run, jack the cooling up quite high. you want 100% reflux, i.e. the reflux jacket needs to take enough heat away from the vapour rising up the column that it will all fall back down the column. These columns are too short to equalise properly, but it is still beneficial to let an even boil get going in the boiler. Let it boil under 100% reflux for about 15 mins (temperature will be probably 50-65*C) , then slowly decrease the cooling, and you will start to separate out distinct fractions in the foreshots / heads. It isn't commonly accepted here but CM is actually very good for heads compression. Remember, take it SLOWLY, nothing good ever came fast. 1 drip per second is what I aim for. It will 'auto shutdown' several times, and you'll have to decrease the cooling again to get the next fraction. Don't rush it.

After a while of foreshots removal (maybe 30-45 mins) you'll be starting to get into the good stuff. As a general rule, the absolute minimum to throw away from three stripped 25l washes is 150mls of foreshots (don't recycle), and then I generally take the next 200-ish ml as heads (ok to recycle) as well and recycle them in my next run. The cut to body is best done by taste and smell, but that will be a problem if you are planning on turbos carbon filtering etc etc, and takes experience to recognize. when you're starting out, using nice, conservative cuts is the best substitute. you may loose a ml or two, but who cares, you're probably getting about 20ish liters off this run.

after you've taken off the foreshots to throw away, and heads to recycle, you should be into the body at about 77-78 degrees. you can then open it up a bit more (reduce cooling) to get a faster collection rate, I sit there and increase the collection rate until I'm happy with the balance of collection rate / output abv.

Remember, collection rate is inversely related to the amount you reflux as well as the abv %: 'the faster you go the bigger the mess'

I personally find that the temperature is easier to set on the 'down stroke', as in decreasing the cooling. I can never quite land it in the right spot when I go to far and have to increase the cooling, so if this happens I put it right back to 100% reflux and slowly start it again. This normally happens several times during a run... the explanation for this is that as you progress through the run, the proportion of ethanol in the vapour going up the column decreases, and it takes more cooling to knock it down. This is a intrinsic disadvantage of the design, and cannot be avoided.

At the end of the run, your temp will begin to 'want' to rise up past 79-80. Your collection will slow quite drastically as well, which will show you that this isn't just a need for more cooling like the the above scenario. This is when you need to switch containers for tails, and keep collecting as much as you can (will require cooling tweaking) until the temp goes past 84 and the collection rate slows even more. Throw the tails and heads back in to the next run to recover the booze.

If you use that method with a nice clean neutral wash like birdwatchers, you won't need to carbon filter, given careful cuts and good control over the temperature for the course of the run. You should be able to achieve 92% on your spirit run if you are careful.

5 Other spirits
As discussed above, these stills detune easily into something approximating a pot still. They ain't perfect, but will do the job.

For flavoured spirits like rum / whiskeys etc, just do two runs through the detuned still, and make careful cuts on the second run. To play this game really well though you'll need an power controller for your element, or a smaller element (high power in a pot still tends to 'smear' the cuts). I'm not really going to go into detail on this, pot stilling is a entirely different game, but knowing that you can use this still for pot stilling recipes should be all you need, pot stilling techniques are discussed in this section of the forum

I hope that this helps someone that did what I did, go to the brew shop to learn about stills rather than home distiller...

Cheers,
Kiwistiller

[HookLine]

Nice work, Kiwi.

[breeze]

thanks, i think i got the idea.

[Usge]

Excellent post Kiwi! These instructions cover a lot of ground for various similar designs (PSII "Extractor" series), and even the Colonel's Rocket Reflux head he uses for several of his designs!

The one thing you didn't talk much about is "heat" levels. Obviously on a strip run you are running it higher heat. But, on a spirit run, when you say to reflux it hard using the internal cooling, you also mention "even boil". My pot won't boil until about an hour in...and that's using "high heat' to start. Are you using high heat, then adjusting down ....while keeping fast water flow to internal cooling so that it compresses it? Or are you using low heat...all the way up to start? That wasn't quite clear to me. Could you expound on that a little more, and perhaps your experiences with variations...ie what's happening at the pot at that point?

Could you post more about how you bring this up to heat...what level of heat you are using...and do you change the heat level at all during a run (or just the cooling). I've modded my Ga Ridge head...adding a 2nd liebig to the output so I can bypass the original design i/o and using the internal auxillary ring i/o for reflux instead. I have a "Y" adapter coming off the faucet that has ball valves on each side, so one water flow goes to my secondary liebig input, and the other goes to the Aux refluxing ring input. Here are a couple of pics:

Ga Ridge 5 gal model with attached secondary liebig:



Auxillary Refluxing Ring I/O (this ring loops around the middle of that cone, and has a finger coil that sits in the middle of head)



Finally, this is the "Y" valve I'm using to separate water flow



I'm guessing this setup is going to respond similarly. I'd be VERY happy with 5 hour spirit runs...given using reflux under original design usually made for well over 12 hour spirit run times.

[rad14701]

Without going too far off topic, that's one damned nice still you've got there, Usge... That optional reflux control really makes that a versatile still... I'm not gonna even guess the price... Really gets my putting solder to copper juices flowing, I tell you what...

[Usge]

Thats the Colonel's work...save for the 2nd liebig. Came with a 2nd gooseneck head fits on the same pot. Bought it a while ago, copper prices were cheaper. Took 6 months wait to get it though and still cost a penny or two. I think adding the 2nd liebig has opened up a way to run it with a little more flexibility, given it separates the liebig cooling from the head cooling from the original design. But, then it just puts it in the same boat in so far as inherent limitations that it and other similar CM designs have (such as the PSII)— hence my interest here.

[kiwistiller]

The one thing you didn't talk much about is "heat" levels. Obviously on a strip run you are running it higher heat. But, on a spirit run, when you say to reflux it hard using the internal cooling, you also mention "even boil". My pot won't boil until about an hour in...and that's using "high heat' to start. Are you using high heat, then adjusting down ....while keeping fast water flow to internal cooling so that it compresses it? Or are you using low heat...all the way up to start? That wasn't quite clear to me. Could you expound on that a little more, and perhaps your experiences with variations...ie what's happening at the pot at that point?

Could you post more about how you bring this up to heat...what level of heat you are using...and do you change the heat level at all during a run (or just the cooling). I've modded my Ga Ridge head...adding a 2nd liebig to the output so I can bypass the original design i/o and using the internal auxillary ring i/o for reflux instead. I have a "Y" adapter coming off the faucet that has ball valves on each side, so one water flow goes to my secondary liebig input, and the other goes to the Aux refluxing ring input.

These stills don't have any control over heat at all. they have a 2400W element in them and they're all or nothing, hence the absence of a heat discussion . There are a lot of these things floating around NZ and as they're a little different to a 'Real' CM with a column I thought a guide to specifically address them might help some folks. So, I guess to answer your question, I'm using high heat all the time. when I talk about running the reflux cooling hard, it is to knock down all of that 2400w. I like to hold it there to get the boiler rolling, I find that this compresses the heads somewhat, I figure this must be something to do with allowing a fast boil to start as opposed to taking off the heads while the boil is just starting (as recommended by the manufacturers of such stills). My theory might be way off but it sorta explains a compressing of the heads so I just tell myself that's what happening and I'm happy

Now in your still you've got quite a bit more column height, so maybe you'd be able to equalize it at the start for heads compression?? Is it packed? if you could equalise (damn American dictionary telling me my 's' is wrong ) it it would be best done under a low heat input. I think snuffy equalises his columns at 700 watts. from their you could power up for the hearts collection.

So, as they don't have heat control, its all done with the cooling. the cooling is slowly stepped back from the start where it is high enough to get 100% reflux, to take of the foreshots and heads very slowly. Then it is reduced in hearts collection until the take off rate / abv is acceptable. because it is a CM, as the abv in the boiler drops, the amount of cooling needed will then increase throughout the run. all of a sudden the water flow will be inadequate and the head temp will rise a few degrees, and water flow must be increased ASAP to stop early tails dragging over. then you have to play the slowly reduce until happy game again.

I hope that helps a bit, but I don't have any special knowledge of your (very nice looking) setup I'm afraid.

Kiwi

[olddog]

Nice and easy to understand Kiwi, I am glad I did not buy one.

[kiwistiller]

Nice and easy to understand Kiwi, I am glad I did not buy one.

I'm glad I've sold mine

[olddog]

Yes I am glad I got rid of my Still Spirits Air still too, I progressed to a standard potstill, and then to my "Frankenstill" improving all the time. Its a pity that the manufacturers of these Still Spirits stills are not interested in the quality of the spirits they produce only in the profits they can make.

[cob]

kiwistiller that translates nicely (with or without the dictionary) to what i am working with. different materials. but enough similarity to be quite usefull. good help thanks. cob

[Husker]

A couple of us twisted kiwi's arm to get this written (lol, not really), since there are many who are just starting out, and obtain a still like this prior to finding a site like HD, and finding out there are 'better' ways of stilling. The still is a safe still, just not the latest design, so if we can help a user learn to better run what he has already plunked down his cash on, it would get that person working, until they chose to upgrade (which they may never do). There were other 'how to use' instructions for an LM still, but those instructions were far from optimal for this type still.

There are others who also have worked at perfecting the run time usage of these CM stills (snuffy is one). Possibly we can expand on this how to, or get whatever changes would be good to make it also work for a taller column CM still. Kiwi wrote directly for the no-column type thing commonly sold in the down under areas of the world (au and nz). The instructions will 'help' with someone running a column CM still, but they are not 'tuned' to that type of still. They certainly will help one get better results from a column CM, but better instructions for that type still would get them even better results.

H.

kiwistiller that translates nicely (with or without the dictionary) to what i am working with. different materials. but enough similarity to be quite usefull. good help thanks. cob

[fatbloke]

Ooooooo ! TVM for that guide kiwistiller.

It explains a bit more of what's going on.

I have used copper mesh in the condenser of my "still spirits super reflux", but it didn't seem to improve the performance of the still (over the "ceramic saddles" that came with it or rashig rings) very much.

I figured that I must have just packed the copper mesh down too tightly as instead of taking 6 to 7 hours, it took 12 hours plus......

I understand the comments about purity etc and would dearly love to be able to upgrade my kit, but here, larger bore copper tubing and the various fittings are hard to get and expensive.

I've also attempted to make a modification for my SSSR still, by way of a 1 metre column extension that uses copper mesh as packing (and conveniently, the SSSR has the same size hole in the boiler lid as 15mm pipe compression fittings - plus the condenser head is the same thread as those 15mm fittings). My first attempt at running it was a failure, it produced spirit at lower strength than just with the condenser head on the boiler, but it was easier to keep at a constant temperature. I suspect it was because I hadn't packed the column extension enough and the vapour just flowed straight through (though I don't really know what was going on).

Is there any magical formula as to how tightly copper mesh should be packed into the condenser heat ? or even down that type of column extension (I just cut a piece too length and rolled it up so that it slid down the length of pipe - which is 1 metre of 22mm pipe, that attaches onto 22 to 15mm reducers at both ends and onto a flanged boiler tank connection at the bottom/boiler lid and a 15mm compression fitting to screw the condenser head on at the top).

Again, cheers for the guide. Brilliant

regards

fatbloke

[kiwistiller]

As far as I know there isn't a magic formula for packing, but it should be firm, yet you should be able to blow through the column. I have seen it recommended for these jacketed type CMs to pack it in really hard at the very top of the column where the cooling jacket is though, to increase the effectiveness of the cooling. I didn't find a major difference in packing that section hard or just leaving it though, maybe a little more cooling require but nothing major. I would have thought that the copper would provide a fairly big ABV lift over the rings?

Yeah 12 hours is pretty damn long... something is not right there. maybe try with a little less packing in there.

[Usge]

kiwi, thanks so much for the response....makes sense. And sorry for interrupting your thread. Yes, I'm using gas heat...so lots of variables there. I'm just getting started into exploring the CM possibilities of my still head and found your information, even though it was about a different still, very helpful. Some of the more advanced CM and other refluxing theory discussions are a little difficult to jump into....right over my head.

[kiwistiller]

No worries. I do think there is potential in CM, paticulary for heads extraction, but it is a fiddly, work intensive design. I think I may mod my VM to have CM heads extractor at some point, If I'm bored... too busy playing with the column for now though

[azeo]

Great stuff Kiwi, easy to understsand, and a great help I'm sure to those just starting, or have had such kit for awhile and found the site. I know someone who bought one a while ago then sought me out, so it looks like I'll helping to make theirs a bit better now that they'v been using it for a while, so this is all good info! I know similar ideas have been suggested elsewhere, but heres some ideas I was looking at to try and modify things for the better. Theirs is a pot still so more of a blank canvas.

While these stills are costing a bit of money for what they are, at least they have a reasonable lid seal and method and form the basis for a good boiler, and the lid has a decent enough hole, even though the silicone could be very inconsistent in thickness, at least on the one that I saw. I wrapped the lip on the boiler with teflon tape, may have done the lid, but can't remember, and that fixed a slight leak, and also possibly reduced the amount of silicone in contact with the vapour, maybe not a bad thing. A few other ideas were to add a second element (available as a spare) and knock up a change over switch ("the Compleat Distiller from Amphora has good info on this,maybe here also?), to run a single element for heat up, and the two in series for simmering. Otherwise I was going to look at a power controller and this would add some flexibility.

My next thought was to add a copper column and condensor, VM would be best I know, especially as they aren't interested in "fiddling" and just want to produce neutrals to add flavours to, but I'm more familiar with CM. Either way I wanted something with only a few fixed settings, but left room for "tuning", just in case once they got really familiar with producing vodka, they were ready for another step. Your ideas sound great, and I may be able to cook something up. Have some grander ideas for my own setup, but that will be some way off!

Cheers

[kiwistiller]

Yeah there are a few more extensive mods that can be done to those stills. I kinda stalled at the thought of getting a bigger column for them, after all its not much more expensive to just chuck that column on a keg and make it a VM / pot combo. I had an electrical engineer make me up a power controller for the element.

Never had a problem with a seal on the lip of the boiler, the steel band worked just fine. The washer sealing my column to boiler was teflon, I'd probably replace it if it was silicone or something like that.

A lot of folks like to take off the synthetic collection tube as well, copper pipe can fit it, add a bit of paste and your done.

Kiwi

[azeo]

for sure that all makes sense! I reckon they'd be really pleased with a 50L keg... The first thing we did was get rid of that plastic pipe too

[Cong]

Kiwi,

Some great info here.

Just in regards to a stripping run.

The standard element on the 25 L boiler is 1380 watt, can an additional element be run for faster stripping or will this overload the poor little thing.

cheers

Cong

[kiwistiller]

the defult element in mine was 2000 watt I think. I know different elements can be purchased at home brew stores. not problem throwing more power at it for stripping.

[sparky marky]

you say to dilute the low wines from a striping run to 40% right?

but is there any danger or other reason why i shouldnt be running them in the spirit run at say 55-60?

[kiwistiller]

a couple...
a charge @ 40% won't reduce through distilalation enough to expose the internal element;
if you're getting that high off stripping runs, you're leaving booze in the wash;
the dilution helps improve neutral flavour, as tastes will remain behind in the water left in the boiler.
Cheers,
Kiwi

[sparky marky]

i see!!
so you are saying that more water in the low wines means that more off flavours will stay in the boiler after a spirit run.

when i said 55-60 i was just guessing since i havnt done my stripping run yet. i will remember to let it run and collect until the alcohol content dies right down. i have another question though... i am running a SS super reflux still and the plastic pipes are glued on to the still something fierce!! i know exactly which pipes i want to move and where to put them to de-tune it into a pot still for a stripping run but they wont come off! has anyone else come across this problem? should i maybe just hack away at them till i get them off and replace them with fresh siphon tubing from the brewshop?

[kiwistiller]

they won't be glued on, but try giving them a bit of boiling hot water - should loosen right off. 20% is where most people strip down to.

[sparky marky]

i thought it was glued because i was pulling at it and trying to coax it off with a knife and it wasnt budging! but the hot water loosened it right up!! thanks

iv got 100 litres of wash that has finished fermenting but im gonna give it till next weekend to clear properly before running any of it.

thanks for the advice!

[kiwistiller]

i thought it was glued because i was pulling at it and trying to coax it off with a knife and it wasnt budging!

Yup, thought so, been there amazing how it sticks on there...

[rad14701]

For plastic or rubber hoses, twisting rather than pulling works better because pulling just makes them grip tighter... Once you twist the hose and break it free you can pull while twisting... You may need to use pliers to do the initial twist...

As for diluting, getting the low wines/high wines down to under 40% is a safety factor because the initial charge will always hold the highest concentration of alcohol... Alcohol under 40% shouldn't burn so if you were to have a catastrophic accident only the alcohol vapor would burn but not the contents of the boiler, whether they remain there or not... Would you really want several gallons of flammable alcohol spewed about the stilling area or just have a flash explosion and then a lot of hot non-flammable liquid...??? This it THE reason you dilute... Start at a non-flammable percentage and be safe for 100% of the run... I don't know that this fact is noted anywhere on the parent site or here in the forums but it would be worthwhile to have it somewhere where novices can readily find it... The additional water does also help retain the nasties in the boiler as well, as mentioned...

[Cong]

I guess the question I was asking was that apart from the heat up time, would another element improve strip times.

My stripping run is very slow, about as slow as a final run, taking several hours from a 25 litre wash.

This is with packing removed and CM reconfigured as pot still.

Is there any suggestions how to speed this up?

cheers

Cong

[kiwistiller]

swap it out for the bigger element for stripping, it is only about $30 for the 2kw element from a brew shop round here.