Stripping still with hybrid air- and water-cooled condenser

[Pierrot Lunaire 55]

Over my years of pursuing this hobby, I've found stripping runs to be the most tedious and time consuming. As a result, I have tried to create a pot still I can run hard to minimize the time. I have 10 gallon boilers (three identical milk cans) and I make mash in 25 gallon batches, so stripping happens in three batches, each pushing over about 5 quarts for a total of 15 quarts of low wines.

Running with a big fire means extracting a lot of heat in the condenser, which means lots of water. My answer to that was creating a pot still with a two-stage condenser, first an air-cooled section using a 4 foot length of baseboard heating finned pipe, followed by a Liebig section to finish the job.

Side view.JPG

Sorry about the cluttered background, but the pot is on the right and enters the enclosure at the top right. The enclosure is a shroud to direct air through the finned pipe, that is driven by a blower on the floor. There are internal baffles to distribute air across the full width. Such blowers are available at building supply big boxes, used by contractors to dry wet floors, etc.

Steam inlet.JPG

The main steam line has a union so I can switch the boiler easily. You can see wires from RTDs I have to monitor temperature in the boiler and column top. At the end of the finned pipe, the line makes a u-turn and enters the Liebig section.

U-turn.JPG

I have mounted an RTD on the section in between and there is a significant temperature drop after the air-cooled section, but the water-cooled section is still necessary. However, the water doesn't heat up nearly as much as it did with just a long Liebig condenser. The data display/collector works great. Here you can see what it shows after making a boiler change. (ignore the date shown) You can see on the left half that the boiler and column temperatures are the same, but then the green line (column top) begins to go down. That's the point where I turned off the gas and once the boiling stops, it begins cooling quickly. Once I have disconnected the union, I can lift off the top to switch boilers. When the next boiler is in place, already pre-heated to about 85 C, the boiler line starts back up immediately and the column recovers partially. If you could see the next section, once it starts boiling again, the column and boiler lines match again.

Display.JPG

I use RTDs for all my measurements. This setup works very nicely and doesn't create gallons and gallons of hot bath water.

One additional aside, the Liebig condenser uses a VERY handy pipe fitting, a 1-1/2 x 3/4 x 1/2 inch reducing Tee, just perfect for making a condenser. I got it at Supply House. Much easier than boring out pipe caps, etc.