Mother's Home-Scale Vacuum Distillery

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As the liquid boils, it gives off an alcohol-andwater vapor, which is driven up the stripper column where it loses its heat to fresh mash coming down the tube. This arrangement—it simply amounts to using mash rather than water as coolant in selected condensers—allows us to take advantage of the latent heat already contained in the rising mist to help vaporize the ethanol within the separately introduced mash mixture ... which will then move up the column with the reboiler-pro duced "steam".

When the vapors leave the stripper circuit, they flow-through the interconnecting pipe—to the rectifier column, where they increase in strength to about 170 proof after passing through the pall-ring packing. Then, in order to maintain a temperature differential between the top and bottom of the rectifier and to keep the upper portion of the packing wet (both of which are necessary to the fractionation process), an internal refluxing heat exchanger-controlled by a temperaturesensitive three—way flow valve—is used to circulate cold water through the reflux section at the top of the rectifier column.

In addition, it's at this point that the 170-proof ethanol is upgraded to 185 proof or higher. The increase in potency is brought about, in part, by the cool heat exchanger (which condenses some of the alcohol—rich vapors within the conduit), and by the introduction of high—proof alcohol from either the storage tank or a separate reservoir. Refluxing as much as 50% of the final product in this manner can increase the ethanol's strength to a maximum of 192 proof. (This supplemental feed tends to create an accumulation of fuel and water at the base of the rectifier column, so the reusable liquid is returned to the top of the stripper column by a sealless magnetically driven gear pump.)

From the rectifier, the fuel vapors go directly to the first stage (or upper section) of the condenser column, where incoming mash-circulating through coiled tubing on its way to the stripper-absorbs latent heat from the passing gases and starts their "precipitation" process. The component's second stage is composed of a Liebig (tube-within-a-tube) condenser surrounded by yet another tubing coil. Both of these simple heat exchangers eventually carry cool water to the tubing maze in the reflux section, but before doing so they condense the remainder of the alcohol vapors passing through the column, as well as any ethanol mist that may exist in the discharged—or pumped-out-air. (The vacuum draw pipe is actually the center tube of the Liebig condenser, so it's kept "droplet-forming" cold at all times.)

After the liquid alcohol leaves the condenser, it passes through a continuous proofing device (made from PVC pipe and Pyrex glass), and then into a storage tank which is, like the still, kept in a partial vacuum. (By keeping the container under negative pressure, too, we're able to eliminate a pump that would otherwise be needed to pull the ethanol from the vacuum system to an atmospheric condition.)

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