This article (?) is the product of my brainchild that I've been tinkering with over the last few years. In a different era, when I ran a forensics laboratory for a relatively unknown military unit, I had to recycle some really expensive (and fairly volatile) solvents. I ended up writing the SOP for the filtration and distillation unit, and it's become etched in my grey matter ever since. I mean, c'mon, just because I retired doesn't mean my brain shuts down, folks! So when the idea is gnawing at you...
As an amateur vintner, I had a 6-gallon batch of apple wine go bad a while back - within a couple weeks of bottling. I think it was cork taint, but the results were unsightly and definitely less than appetizing. I could dump the whole 6 gallons down the sink, or do something to salvage all that labor. I chose the latter approach, but most certainly had my work cut out for me. NOTE: The standard disclaimers apply, all we can do legally in these United States is distill water and fragrances, anything else is verboten without a license and plenty of excise tax being paid.
Great. Now that I have that legalese out of the way, let's talk about a hypothetical way to refine a given solution's composition, shall we? Having that old USAF SOP in hand, with vivid photographic memories of the setup and operation, I proceeded to find assorted parts and pieces. Some were used, some new, some off-the-shelf, others kitbashed. I've actually got hose clamps, picture wire, and duct tape in there for good measure. As for sources, the local state university has a retail surplus store, and of course, there's always eBay. The system I've assembled is currently at Version 4.0, if only because I've learned over time to improve things, either by studying up on the process, or by simple trial and error. I'll illustrate the earlier versions in another blog post - the current system warrants discussion in the here and now. Ready? Here goes the illustration of the Model 188 Batch Rectifier...
Boiling a liquid mixture of mostly ethanol and water is kind of a running compromise, because as you boil out the more volatile component, you run the risk of sending the stuff you don't want out the top into your collection as the former dwindles in concentration. There are different peaks on the temperature curve where stuff comes out of solution, and you have to pay attention to the timing and characteristics to make proper "cuts". This allows you to discard stuff you don't want, and keep the stuff you do. Learning how to make those cuts is a major part of making something worthwhile vs. something just plain awful.
Once the vapor you're looking for is heading northwards out of the boiler, you've got a couple of options. You can collect it and condense it right away, which is called "pot still" mode. That guarantees more of the parent liquid's flavor will remain, but also makes for a much lower proof for a given run. To bump the proof higher, you have to re-distill the output of a previous run, and keep doing that until you reach the target proof. Pot stills are the favorite of the whiskey and bourbon industry, hence the "Double Distilled" and "Triple Distilled" labels on your favorite bottle of hooch. They're looking to retain the grain flavors in the finished product, be they corn, barley, or rye.
If you want to take things a step further, another option is to introduce some quality control to the process, by way of packing the column above the boiler and returning the majority of the vapor back to the boiler through that packing. This is called "reflux still" mode, because it refluxes the vapors continually, letting the purified vapor escape out the top, while sending the impurities back down the column for another go at it. This provides a much higher proof (188 proof, or 94% ABV in the case of this particular setup), but also a more neutral spirit, very clean and with minimal residual flavor.
|The Dephlegmator (aka, cold finger)|
|Reflux heading back down into boiler|
|Sending it all back down the column!|
|Ice-cold mountain stream, micro version...|
|How do you keep that ice water moving?|
|Both condensers and their plumbing...|
|It's raining in there!|
|The whole system in operation, small footprint...|
|One drop at a time.|
|That's right - 188 proof!|
|It takes patience, a lot of patience!|
|How do you do?|