Air Stills (a.k.a. Easy Still, Mr. Distiller)

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Usge
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Air Stills (a.k.a. Easy Still, Mr. Distiller)

Post by Usge » Sun Aug 22, 2010 7:18 pm

Here's a basic guide on Mr Distiller/Air stills, etc.


There are several variations of this type of still, which are based off a common water distiller design with air cooled coil over a stainless pot and electric coil heat in the base. The"still" models differ from the "water" distillation models in that they increase the fan speed for more cooling on the coil/condensor..while reducing the wattage/heat to the coil in order to optimize it more for distillation of alcohol. Some newer models include variable rheostat settings for fan speed and/or heat making them in theory somewhat more adjustable/tuneable. In practice, those additions don't really alter or change the basic operation of this still significantly. The basic models are pre-set..and pretty much run themselves. Although there is no denying the stealth factor with these things, there are functionally much better alternatives out there, particularly for the money. But, if you are intent on using one of these, or already have one...here's some tips that might help you work around some of the more common issues I've run into using mine.

Here's a typical Mr. Distiller model package:
MrDistiller.jpg
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And here is a corresponding typical water distiller version:
CountertopWaterDistiller.jpg
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They look identical, but they are not quite. The Mr Distiller model has been modified with lower wattage/heat..and higher fan speed, to increase it's reflux for distillation of alc (instead of water). But for all practical purposes here in regards to mods, assembly, and general issues, etc., these stills are nearly identical.

Some of the more common issues, particularly with water distiller models, or basic designs...is the use of plastic for the distillate to exit through the nose, the distillate being warm-hot, puking through the top/head, leaky head gaskets and thermal shutoffs if the bottom gets too hot and the water distiller model has a chlorine vent/release opening towards the end of the coil inside — that must be sealed up (a drop of solder will usually do it) to use it for alc. I'll cover these separately, but first lets see how to properly disassemble a base core unit model. There may be some variations, particularly in more recent temp controlled models, but this should get you in the ball park.

Disassemble
To disassemble the coil from the head, first...make sure the main A/C is unplugged. There is also an A/C cord that runs the fan in the top of the head that is pushed into a socket in the back of the unit. Pull this out/away from the pot. You can now lift the head off. The lid/coil/fain all comes off as one unit. Take the gasket off (* Make note of it's position, angle, etc..cause if you don't put it back on "exactly" the same way, it's going to leak. Take pictures if you have to).
Head_gasket.jpg
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Remove the screws holding the top plastic vent cover to the bottom plate. Now the coil and nose is exposed. The coil has fins that rest on plastic supports but it's mainly held in place by a silicon gasket in the top of the lid. At the nose, you may find some sort of plastic bag/tube, etc., fitted to the end of the coil, or that it drips into. This is the stuff we want to remove. Make sure the end of the coil is not attached to any plastic/rubber tubes, bags, etc. Make note of how the coil is seated into the plastic head (ie, where the fins are seated, etc.)
Head_coil.jpg
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Removing the Coil
To remove the coil, push the coil tube up "through" the top of the lid, as you work the coil loose from above (applying gentle upward pressure). It takes a little bit of fiddling but it will lift right off the top of the head. Be careful not to bend up the fins.

Mods
Now, there are couple of ways to deal with getting your coil extended to copper/stainless and avoid the plastic. Attach one end of a 90 degree stainless compression fitting to the coil, and a copper tube to the other end. Bend the copper tube out slightly to adjust the angle. If you are using a water distiller model, seal up the chorine vent opening with a daub of solder while you have the coil out. You see it towards the end of the coil. It's the only "hole" in the coil other than the 2 ends.
Head_PlasticNoseCut.jpg
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Cut the bottom of the plastic "nose" out with an exacto knife as far back as needed so the fitting and tube has room to sit and pass through the nose. Once you have the copper outside the nose, you have some flexibility as to length, positioning, or additional things you might like to attach. Slide the new fitting/tube down through the nose as you lower the coil back on to the head. Make sure it's seated properly onto and thru the head and sitting/seated at the other end.
SS_compression-fitting.jpg
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The other way, to deal with this, would be to use a copper 90 degree fitting..that fits the coil tube. You can either try soldering the copper to the stainless tube (you have to use the proper flux for this), or you can just wrap the end of the tube with enough PFTE thread tape to push-fit the fitting on tight enough that it doesn't leak. Solder a copper tube to the other end of the fitting and again, you'll need to bend it some to clear the angle of the pot. Then, again slide the new fitting/tube through the nose, as you lower the coil back on top of the head.

Replace the cover and screws and replace the gasket "exactly" as it was before. Put some water/vinegar mix in your pot...and carefully lower the head straight down onto the pot so as to seat the gasket properly. Reconnect the head fan A/C cable to the back of the pot. Then plug the pot in and hit the reset button, if needed, to start it. Let a cup or 2 of water/vinegar mix run out and check for leaks in and around the head/gasket and at the coil/nose fitting. If everything checks out, unplug it, let it cool, break it down and rinse out the pot and coil with water. You are now ready to run some alc through it.

Now that you have copper tube coming out, you can from there do additional mods ...such as attaching a 2ndary liebig condensor to help cool the distillate even more.

The other place that might need attention on these basic models is the top of the lid. You have to be "very" careful not to overfill these these things...as it will suck it up right from that coil tube into the head, and puke it out the other side. The mod for this is to attach a small "tab" or deflection plate that covers/protects the inlet so that wash splashing or foaming up, doesn't just get sucked directly up into it. It won't stop it from puking if you over fill it, or get a very foamy wash. But, it will stop it from splashing up into it. Some alc "distiller" models may already have this mod in place. But, most water distillation models do not. The other thing that helps here is boil chips (or just pieces of copper in the bottom of the pot) to help keep the boil even.

Operation
As to operation...there really isn't much to these. You fill it to the marked line, carefully place the cap to seat the gasket, plug it in and go. You can't control the heat — it's thermostatically controlled by the built in heating unit. And the cooling is controlled by the fan speed which is also pre-set. As stated previously, the alc "distiller" versions of these have lower wattage/heat and higher speed fans. The water heater versions have higher wattage/heat and distillate will typically come out warm/hot. I would only consider these (water distiller models) if you plan on using them to strip wash. The high heat makes them work fine for stripping out wash, but would only make the small size, cuts issue more difficult. These units main advantage is 'stealth'. They look totally unassuming even just sitting out on the counter. Of course, protruding copper pipe and/or liebig, etc., might make it less so, but it doesn't really negate this advantage. The main draw back here is "size"...and flexibility. 4L, which is standard base model size, is just simply not enough volume, and not enough control over heat and cooling to make any kind of clean cut on. But, while it does operate pretty much without much attention needed, you can NOT leave it unattended. You'll still need to stop it, turn it off at your stopping point. Otherwise, it will just keep running till it runs everything back through/dry and shut off. You'll then have the same wash you started with..only in a different pot! The other thing I found was..because copper tends to heat/cool rapidly, if your distillate is coming out hot/warm, and you are using the mod above to attach copper pipe, the pipe itself will get hot/warm. So, careful there as well.

Another issue that cropped up on mine was...if your wash/mash is too thick..it can burn on the bottom, which will cause it to do an auto-shutoff. You can try hitting reset to restart it..but most likely, it will just shut off again and burn whatever is stuck to the bottom even more. Your best bet is to wait till it cools, empty it out, clean/scour out the mess, and thin, filter/clear the wash more before trying again. Some of the newer models with variable temp, may not be quite as sensitive to this particular issue, but the ones with built in temp/thermal units that are non-adjustable might be more prone to it.

Because of their small size, they typically bundle the alc distillation models with instructions and ingredients for turbo/high gravity washes to compensate for it, and use charcol/filtering to try and make up for the smeared run of nasties. There are much better/cleaner alternatives in the proven recipes forum. But, for all practical purposes, this operates as a very small basic Potstill, and as such..probably might do a better job at making a flavored product (brandy, whiskey, etc) than it would trying to make something like vodka or neutral (it just doesn't have enough reflux for that). You can always run it through multiple times and keep filtering it till you get it clean enough. But, for 200-300 dollars you could easily build a VM reflux still from common parts that was more suited to the task. Or a better/bigger pot still for that matter. Other alternatives if you don't want to build yourself include the more appropriately sized stainless/milkcan or stainless CM stills they also sell, and portugal copper alembics which can be had in smaller sizes for the same price and are more suited for the task at hand. They aren't as stealthy, but they are much more flexible and are available in large enough sizes to make doing cuts more manageable.

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