Stove Top Distiller

I had a two batches of over-ripe kombucha and water kefir. Did I dump them? Nope. I distilled them (I recommend dumping it instead, it doesn't exactly make good salad dressing when distilled). Here's an instructable on how to make a simple stove top distiller that can be used for a variety of distillation tasks. I plan to use it further to distill citrus oils.

Step 1: Bend the Copper

Copper tubing is used in this distiller because it's sold at the local hardware store. With copper prices being what they are, it is only used for the condensation coil rather than all auxiliary tubing. Copper is necessary (aluminum may be a possible alternative?) because it facilitates good heat transfer between the steam and cooling water.

The key to bending the copper is to bend it as few times as possible, and to use sand to prevent it from kinking:

1. Drill the bottom of a container so that it fits over the copper tube.
2. Cap the bottom of the copper tube with tape.
3. Fill the container with sand.
4. Rotate the tube to transfer sand into the copper pipe. Refill as necessary.
5. When full, remove the bottle and tape the copper tube.
6. Wrap the tubing over a wine / glass bottle.
7. Pull the coil apart slightly to add gaps.
8. Remove the tape.
9. Rotate the coil to empty sand.

Step 2: Bend the PEX

Because copper has become more expensive, PEX (cross-linked polyethylene) tubing is being used more and more in homes for water piping. There are two types available: red and white. White is used for cold water and has a lower working temperature. The pipe used below was what I had at my local hardware store and is rated for 180 ºF (82 ºC) at 100 PSI (6.9 bar). This is well below the temperature of distillation, but that's okay because the pressure involved is probably no greater than 1-5 PSI.

I tried different methods of joining PEX but it's horrible. Unlike HDPE it cannot be cut and joined. The next best method is heat bending and using sand to prevent kinking.

1. Tape one end closed.
2. Put container over other end.
3. Fill with sand.
4. Tape container end closed.
5. Heat over flame and rotate.
6. When flexible, bend and hold until cool (lazy: tape it to the floor).

Surprisingly, the tubing keeps its shape and does not soften, despite clearly exceeding its recommended operating conditions.

Step 3: Make the Chiller

The chiller body is made using an HDPE jug because it is found everywhere and because it melts at a temperature higher than boiling water. This particular jug was from an oil change and the top was removed and the body was cleaned before drilling.

1. Remove the top of the jug leaving just the base.
2. Clean the jug.
3. Drill a hole 20-25% of the remaining height somewhat smaller than the PEX tubing for the outlet.
4. Attach the PEX tubing to the copper coil (hand pressure is sufficient).
5. Put chiller into container.
6. Make and use a support for the heat exchange coil out of spare steel / coat hanger.

Step 4: Lid Preparation

To drill a center hole in the lid (slightly smaller than the PEX Tubing):

1. Trace the lid.
2. Square the circled trace.
3. Cross the square.
4. Dent the lid.
5. Drill the lid.

Step 5: Assemble and Distill

The distiller body is made up of a paint can because this was available at the hardware store, was inexpensive, and could be sealed.

1. Fill the paint can with fluid. Try to fill no more than 2/3rd to allow for boiling bubbles.
2. Hammer the lid shut using a rubber mallet.
3. Put the paint can onto the stove top.
4. Connect the chiller assembly.
5. Use plumber's putty to seal the very top.
6. Add water and ice to the chiller tank
7. Distill.

In about 1 hour, I got 4 cups of distillate. The first batch smelled fruity because of some aromatic esters, but the last batches smelled like vomit because of butyric acid from the kombucha. Hopefully citrus will be more pleasant. The one upside, the distillate attracts flies so it's a good way to catch them if they fly around the house.

Lastly, don't forget to wash the copper when done, especially when distilling organic acids!