thumper test

I've been thinking about building this thumper for a few months now.  I finally decided to stop the planning and build the damn thing.

My plans were a bit more elaborate than the finished project, and it was that way of thinking that kept me in a holding pattern.  The original plans involved building a new column with a 2" to 1" reducer with a 90 degree elbow connected to a 3/4" copper pipe through the dome lid with an equally elaborate exit pipe connected to the liebig condenser.  All of these parts connected with compression fittings for easy assembly and disassembly for cleaning.

As I mentioned, all this planning only got in my way of building it.  All the measuring and constantly searching hardware stores for parts they don't carry kept this project in a perpetual state of limbo.

I decided to just build the damn thing freeform and see where it goes.  Where it ended up was a rather efficient second distillation thumper, despite a few minor flaws.

The parts list was simple... A 3 gallon stainless stock pot with a stainless salad bowl as the dome, a few feet of 1/2" copper tube, a couple compression fittings, some foam seal, and some spring paper clips to hold down the lid.  Soldering copper to stainless was the tricky part and that was easily accomplished by acquiring the proper liquid flux from Amazon, since no hardware store around here carries such a thing.  Some reinforcement to hold the dome pipes in place and it was ready to run.

The first test was distilling water to test the seals and compression fittings.  Good thing I did because the foam seal between the stock pot and dome blew out on one side.  (The last thing you need is alcohol rich vapour near a heat source.)

If this test was distilling alcohol I would check the proof, flavor and measure the consistency throughout the run, but since this was a water run I did a few tests on total dissolved solids.  The end result from the thumper showed a TDS count of 4 parts per million, or 4ppm.  The water left in the thumper showed 55ppm while the cooker registered 86ppm.  Since the water I started with had 71ppm, I can only assume the cooker and thumper vaporized only H2O, leaving a concentration of dissolved solids in the boiler and thumper, with decreasing TDS at each stage.  Going from 71ppm to 4ppm is pretty good, considering my boiler was cranked up to 220 degrees.  I believe I could have reduced that 4ppm if I reduced the heat a bit.

It seems this thumper did a good job purifying water.  What it will do to a ferment wash is something else.  My main interest is to carry over the flavors from the wash, not eliminate them entirely.  I think I can achieve this by charging the thumper with some backset from the still along with some tails from a previous run, allowing the desirable flavors to pass while maintaining a more consistent proof.

I'll let ya know after I fix that broken seal and try again.