Thursday, February 19, 2009

Pot Distilling 101

After three days of trial and error, we have our procedures pretty well established:

First, we drain all of the spent mash out of still #2. It is such a good beer still that we want it back on line first. Next, we shovel the ashes out of the fire box, and take the head off the still so we can inspect it and re-fill. (As a reminder of why it is good to take the time to inspect the interior every time, we found a big glop of solids in the bottom of the still that we needed to clean off, or it would have baked into cornbread after another day's distilling.) Then we fill the still to about 60 percent capacity, rebuild the fire, reassemble the still (put the head back on and reattach the arm), and begin filling the worm tub (condenser) with water. Finally, we balance the water flow in and out of the tub to ensure an optimum stream and optimum cooling capacity. Then on to still #1.

Once both stills are running, we monitor the water in the condensers and adjust as necessary. Eventually the distillate begins to flow, a few drops at first but soon turning into a steady stream. The first part (known as the "heads") is of poor quality, so it gets dumped back into the fermenter to be redistilled later. Once the quality is good (at least 40 proof, but usually much higher toward the beginning of the run), we collect the product and set it aside to be distilled a second time. The main purpose of the first distillation is to separate the alcohol from the mash, but the proof will be relatively low. If it averages 40 proof we are happy.

When the proof drops into the low 30s, we cut off the distillation and either start over from the beginning, or half-empty the still and refill it with new mash. Dave calls this procedure "turn and burn," and it allows us to extend the still run with less down-time. We leave the fire hot and empty one-half of the still volume through the outlet drain, then refill with fermented mash. The folks who made our stills, Vendome Copper and Brass Works of Louisville, KY, convinced us to let them include a small vent hole in the base of our stills, as a pressure release device to keep us from blowing ourselves up. The hole also acts as a handy inlet for adding mash, and its existence is crucial to the turn and burn maneuver. You have to be quick so as not to scorch the contents of the still, but it is a real time saver.

We hope to have enough first-run distillate available later today to be able to start running the "spirit still" -- where we distill for a second time, and hopefully increase the proof into the 100-110 range.

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