Why I like my CM/VM still...

[diesel4ever]

I've been reading alot about the advantages and disadvantages of the various still designs here and I have got to vote for the CM still design as the best technology for a reflux still. For all you people who like to have "mash flavored product" and aren't interrested in neutral spirits you can skip this post.
The reason I chose the coolant management system (CM) is in my opinion there is no more accurate way to make cuts. I can accurately control the temperature of the reflux cooling chamber to allow only heads to be extracted initially. My thermometer tells me what chemical is going to be condensed by it's boiling pt. In a standard sugar wash of 5 gal. at 13% ABV I can generally start keeping hearts after only collecting about 6 ounces of heads and tails are easily destinguished because when the volume starts to slow down I'm getting close and I start collecting in 2 oz. increments until either I start to taste tails or most likely the temperature will change (generally no more than 0.2deg. F). After that I just shut everything down because there won't be more than 4-6 oz. to collect and it's so slow it will take over an hour for that little bit.
Yes It's probably a little slower than other methods. It generally takes me about 5-6 hours from the minute I fire up the boiler till it's shut off for a 5 gal. batch. But I don't have to do stripping runs and the product is ready to drink right now! Well after I dilute it anyways.
Yes my still was somewhat more expensive and tricky to build but I've been completely happy with the design and the only modifications I did was to add a keg boiler.

[Gilbilly]

Do you use a recirculation tank or city water for cooling?

[diesel4ever]

I'm on a well so I run the still when I'm watering the pasture, yard or garden during warm weather so the water temp stays constant and my output water waters the garden. A coworker was so fascinated with mine that he bought one from Mile-high and loves it! He's on city water though and runs his cooling water from a sink. If I wasn't on a well I'd probably want to run mine out of a recirculating tank. You could probably use a submersible pump with a bypass feature to keep the water circulating and an overflow drain hose near the top. You'd have to keep adding bags of ice though to keep the temp constant.

[airhill]

If you stick a thermo probe just over half way up the packing (there is a sweet spot) doesn't have to be accurate, a K type shoved under the insulation will do it will give you a warning (time depends on how hard you are pushing your boiler) before tails will arrive. Did this on the CM and now the bok (takes a bit of the fun out of it though )

[LWTCS]

If you stick a thermo probe just over half way up the packing (there is a sweet spot) doesn't have to be accurate, a K type shoved under the insulation will do it will give you a warning (time depends on how hard you are pushing your boiler) before tails will arrive. Did this on the CM and now the bok (takes a bit of the fun out of it though )

Thats what I am trying to get worked out for my rig

[airhill]

Two things about thermometers. they are usually inaccurate over time and at certain ranges and always get one that responds rapidly (its movement you are looking for).
Unless of course you are fairly wealth and buy the best and get it recalibrated regularly.

[diesel4ever]

I'm lucky, my thermometer is very accurate and very quick to tell me of any suttle changes in vapor temp. I checked it with boiling water last month because I was having variations in my hearts temperatures and it's still right on the money. The variation I was getting had to have been from barametric pressure fluctuations because when I noticed the change was when it was storming outside. Too bad they don't make a remote thermometer that is as accurate as the cheap poker ones.

[Ayay]

its movement you are looking for.

If your thermometer can read 0.1*C then it's good. No matter what the actual number, the subtle change from say 78.2 to 78.3*C is what youre lookin for.

[airhill]

And/or get used to thinking in Fahrenheit (its a longer scale)

[diesel4ever]

My thermometer works in both F and C and in tenths of a degree for each.

[kiwistiller]

How does it function as a VM? Do you add an extension to the top or something for another condenser? I don't see a valve, do you run it at a fixed reflux ratio?

[olddog]

Nope no valve there Kiwi, I just had a close up look. But there again Diesel is an expert still developer, he's probably got one hidden somewhere.


OD

[diesel4ever]

Ouch... OD stop! You're going to make me cry! As you know LM stills only have one way to control output and that is by a needle valve which controls liquid (L). A True VM still controls output by valving how much vapor (V) escapes past the reflux condensor. My still also controls how much vapor escapes past the reflux condensor but it does so by valving the flow of coolant through the reflux condensor... SO that's why I put CM/VM on the heading of my post.

[kiwistiller]

Ah ok. Just so you know, you're pretty much entirely incorrect on what a VM does. You just described a CM twice.

[rad14701]

Ah ok. Just so you know, you're pretty much entirely incorrect on what a VM does. You just described a CM twice.

And here I thought I was reading things wrong even after several re-reads...

A VM works be redirecting a portion of the vapor into the product branch where it is condensed... No vapor ever travels beyond the reflux condenser which should be knocking down 100% of the vapor rising up the column...

Perhaps you just mis-articulated in your post, diesel4ever...

[diesel4ever]

Oops, thanks guys. Too high a blood alcohol content apparently. I meant to say the VM "bypasses" the reflux condensor via a gate valve. Is that better?

[myles]

Perhaps I am looking at it wrong but I just can't see it.
This is my next evolution which is a CM / VM build.



The reflux condenser has 1 preset flow rate intended to stop all output from the upper (CM) port with the boiler at 700w. Stabilise at 700w then slightly increase boiler input to bleed off the heads.

Open the second flow controll to shut down the output, re stabilise and then open the VM output valve. At this point the upper port becomes the air vent for the VM. As a quality check if you get drips of condensate from the upper port (during the VM run) then you are putting in too much power.

[kiwistiller]

Oops, thanks guys. Too high a blood alcohol content apparently. I meant to say the VM "bypasses" the reflux condensor via a gate valve. Is that better?

Where is your gate valve on it? I couldn't see one.