Lava Rock vs SPP vs Stainless Scrubbers - TEST

[Northsouth]

After searching this forum and reading anything I could come over about lava rock and SPP, there were still some unanswered questions. This is an intent to at least try to give some clarity in the difference between the 2, and also compared to scrubbers.

Setup:
For the test, I tried to keep everything as constant as possible, but there are some variations, especially in ambient temp. and some in cooling water. Pot has 3x1000 W elements, 2 in parallel. Use a simple plugin SCR for power control. It can be connected to either of the two loops (1000 W or 2000 W). I have a 2” (54 mm) CCVM, and used it with the coil in a fixed position. Also made a 4 pipe dephlag, but find it harder to control flow (only have 1 pump and therefore use tap water), hence went with the CCVM.

Setup.jpg

For cooling temp of water, I use a 50 l bucket, run a garden hose to the bottom where the pump suction is, and let it overflow at the top. This keeps a relatively stable temp, and a steady flow, but it can vary 5-10 degrees, since I try to reduce the water consumption.
Column used was a 500 mm 2” with following packing:

1. Lava rock, one scrubber on bottom, one on top. 400 mm Lava rock sized to 5-10 mm. Did not make them round, just hammered away until reasonably small.

2. SPP, one scrubber on bottom, one on top. 400 mm SPP, homemade.
(0.8 mm MIG wire, size approx. 5.5 mm x 7.5 mm, read here it is too big for 2", but did it anyway)

3. Stainless scrubbers, full 500 mm.

Packing.jpg

Wash was cheap wine, 13% ABV according to label, each batch 13-14 l. (3-4 gallons). Note that it is the first time I run the SPP, or any SPP for that matter, so results might have been a bit different with more experience. With the coil in fixed position, maybe not though, understand the idea of SPP is to run hard both reflux and power.

Stabilized column took off 200 mm foreshots while running slow. Still is outdoors, so some difference in temp. for the 3rd run with 4-5 degrees higher air temp. Measurements were taken well into hearts, after approx. 0.7 l takeoff. Idea was to let 30-40% of the total alcohol in the wash pass by to be in hearts.

ABV:
1. Lava rock: 93.5 ABV at 17.5 deg.C = 94.0 ABV
2. SPP: 94.5 ABV at 19 deg.C = 94.7 ABV
3. SS: 95.3 ABV ar 21 deg.C = 95.1 ABV

ABV.jpg

Not what I expected at all, but these are the results.

By the way, I never ever get beyond 95.6 no matter what I do. (I have written otherwise here in the forum, but later realized this was due to failed temp. awareness).

SPEED:
After former readings, tested different power input. Note that coil was always untouched. Observed the following:

1. Lava rock. Around 1500 W, the flooding started, and had to ease off, aggressive fizzling in column.
2. SPP. Increased to 2000 W, then to 2500 W, even ran full 3000 W for a time. ABV dropped to approx. 92-93%, but no flooding.
3. SS. Could run steadily at 2000 W without flooding, Beyond that, about 22-2300, flooding began.

Taste:
This one might not be fair, as my cutting skills are very poor. I go mainly by smell. Nevertheless, the following was observed after tasting:

1. Lava run. Tailsy.
2. SPP. Very neutral.
3. Different, more taste, not tailsy.

After.jpg

Other:
1. For lava rock, it took 2 afternoons to pick out rocks and hammer down a couple of bags (5kg BBQ bags). I DETEST the smell of tails, and lava leaves a lot of that smell after a run, and is hard to clean. Only alcohol can make it smell better I think, water won't do it.

2. SPP is expensive. If homemade, you must first find a suitable wire, for most, that is not free either. Did not go totally berserk in making an automatized process, since I figured it would be a one-time deal (neither do I have the skills). Making a mandrel is not hard, winding it is relatively easy. Used just my (gloved) hands, a square patterned slipper on my foot to apply tension, and a fixed drill. And a helping hand to hold back the wire from springing off the roll. Have 3 l now, and winding took about an hour in total. Cutting it on the other hand… be prepared.

3. SS. Cheap, easy.

One thing that was brought to my attention with lava rock was the following:
Before using it the first time, I cooked it on the grill in an aluminium foil until it dried out. After the hammering, there was a lot of red sand and/or substance dried out at the bottom. After using it, I left it in jars. During this test, one of these jars were washed in soap and hot water, and used for cuts during the test. Look at the photo. That is after full wash, and with 94-95 ABV alcohol inside. Unlikely that whatever that is goes up with the vapor, but some food for thought.

glass.jpg

That is what I had, hope it can be of interest.