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.

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.

Lava, SPP, SS

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

Lava, SPP, SS

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.

Lava, SPP, SS

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.

Stain on glass

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

[bitter]

Interesting test. I think you need taller column 500mm packing is not much.

My 3 inch boka will have close to 1.3m of spp for packing. Now it's made testing soon


B

[ShineonCrazyDiamond]

Give this a read.

viewtopic.php?f=1&t=30727

[StillerBoy]

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.

1. Lava rock: 93.5 ABV at 17.5 deg.C = 94.0 ABV

The issue you encounter with the lava rock abv was due to their sizing being to big.. and not packed property.. especially on a 20" (500mm) column.. the size for that length should have been about pea to rice size..

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.

As to the lava rocks retaining the tail smell, a hot water rinse and a hot water soak with some white vinegar will do the trick for the tail smell..

Lava rocks properly size will do the same abv as SSP , using the same power range any day.. and are much easier to do than SSP..
Mars

[Oatmeal]

Oh man, nice work Northsouth! I've been wondering how your spp project has been going. Glad it's coming along!

I'm planning a comparison between lava and scrubbies here in a bit. Have some wash waiting, but need to make some vodka, to address an upcoming gin crisis. Will also use ccvm to set the same reflux ratio....

The issue you encounter with the lava rock abv was due to their sizing being to big.. and not packed property.. es

I based my rock size on a post by houndog saying they should be roughly dime sized. Can you direct me towards a discussion of lava rock sizing vs column diameter? (I greatly appreciate many of your informative posts, thank you!)

Edit: Stopped being lazy and searched - This discussion has some relevant info to this thread and my query...Now just downright embarrassing- Another fine discussion. Should only post when drinking coffee ( le sigh)

[RC Al]

The sizing listed for marbles still applies, 10-12% of diameter.
It's to do with open vs packed area, 65% packed is meant to be good, the above ratio gets you there.

[Northsouth]

Give this a read.

viewtopic.php?f=1&t=30727

Already did, ALL the 19 pages, every post. But yet felt this test was needed. Guess I needed to see for myself.

[Northsouth]

Interesting test. I think you need taller column 500mm packing is not much.

My 3 inch boka will have close to 1.3m of spp for packing. Now it's made testing soon


B

I also have a 1.2 m column, so far only ran it with copper mesh. It takes me to 95+ as well, but slowly, 1000-1200 W max. It is kind of abandoned, as I am moving into 3", started at the bottom with a 350 mm glass column.
The point of using the short 500 mm stripping/playing column was to see if any of the packing types would stand out and shine. The all did really, all gave ABV of 94+.

Also had good results with lava rock in earlier runs, was using the 3" 350 mm, AND the 2" 500 mm on top.

I will make a bold statement here and say that you don't need same diameter all the way to the top if flooding is the issue. There is more flow going down at the bottom than the top, so after some height. Any views on that, anyone?

[bitter]

Dad300 mentioned a bunch about 36 inches of spp. Your just under 20 inches. Love hearing spp way cleaner. I'm going more for my 3 inch hops for super clean and wider cuts for neutral as well as decent speed.

But its really nice to see the results and makes me happy I am going spp.

B

[Northsouth]

Oh man, nice work Northsouth! I've been wondering how your spp project has been going. Glad it's coming along!

I'm planning a comparison between lava and scrubbies here in a bit. Have some wash waiting, but need to make some vodka, to address an upcoming gin crisis. Will also use ccvm to set the same reflux ratio....

The issue you encounter with the lava rock abv was due to their sizing being to big.. and not packed property.. es

I based my rock size on a post by houndog saying they should be roughly dime sized. Can you direct me towards a discussion of lava rock sizing vs column diameter? (I greatly appreciate many of your informative posts, thank you!)

Edit: Stopped being lazy and searched - This discussion has some relevant info to this thread and my query...Now just downright embarrassing- Another fine discussion. Should only post when drinking coffee ( le sigh)

Thanks for the support Oatmeal. I am a total beginner here still .. pun inteded.. and it is amazing how much info you can find in here. Trouble is this is a forum, not a textbook or a work procedure, so you can read literally thousands of posts without being able to put the pieces together. I think I actually read the post from StillerBoy already about the different performances, not unlike this one actually, but there are others expressing other opinions as well, and therein lays the problem. Guess we have to read-do yourself-then read again. I am packing away soon for the summer, don't have a permanent setup as you might have figured from the photos, and will go into the read more, do less - phase.

About size of rock, mine are actually not so consistent, as I just hammered away until it looked around 5-6 mm, I think some of it was bigger. They are not equal in length/width/height though, totally random. (The photo is misleading).

Anyway, this was not a very scientific test. Main intention was to see if there is a huge difference, since I have read here that HEPT for SS is 10-12 cm, and SPP possibly as low as 2-3 cm. No one have come up with HEPT for lava rock, as far as I could search, there was a full thread with that.

Suspect skill is a larger part of it than I thought.

[OtisT]

Thanks for the write up. I’ve been using lava rocks in my 4” packed column. They call it Cinder Rock here at the rock yard. I’m not planning a comparisons to the mesh packing I used in my other columns, but I hope to compare rock sizes at some point. I’ve been running rock that passed through a 3/4” screen but not through a 1/2” screen. Next I’ll be using rocks that passed through the 1/2” screen but would not pass through a 1/4” screen. It’s a short column so I’m not getting 92% now, and hope to see a small increase with the smaller rock. Time will tell.

I never had issues with rock particles coming through with my distillate. I wonder if you were running too hard and maybe don’t have much height between the top of your packing and the vapor outlet? I did see a red rock sediment in my boiler after a run. I washed the heck out of my rocks in water before use to free most of the dust. Lots of sediment in that wash. I saw some red dust sediment left in the boiler after the first few runs, and the amount diminished to virtually nothing after 3 or 4 runs.

Otis

[StillerBoy]

Thanks for the write up. I’ve been using lava rocks in my 4” packed column. They call it Cinder Rock here at the rock yard. I’m not planning a comparisons to the mesh packing I used in my other columns, but I hope to compare rock sizes at some point. I’ve been running rock that passed through a 3/4” screen but not through a 1/2” screen. Next I’ll be using rocks that passed through the 1/2” screen but would not pass through a 1/4” screen. It’s a short column so I’m not getting 92% now, and hope to see a small increase with the smaller rock. Time will tell.

I never had issues with rock particles coming through with my distillate. I wonder if you were running too hard and maybe don’t have much height between the top of your packing and the vapor outlet? I did see a red rock sediment in my boiler after a run. I washed the heck out of my rocks in water before use to free most of the dust. Lots of sediment in that wash. I saw some red dust sediment left in the boiler after the first few runs, and the amount diminished to virtually nothing after 3 or 4 runs.

Otis

I've never worked with lava rocks as packing on a 4" column.. but I've worked with 1.5" to 3" column.. for the 1.5" column with rice size (almost all the same size) on a 24" column, it will give 95% at 1L per hr.. for a 2" column with 3/16 - 1/4" size on a 33" column, it will give 95% at 2L per hr.. and for a 3" column 1/4" - 5/16" size on a 34" column, it will give 95% at 3L per hr..

In my view, of all the experimentation with the rocks size, it's important that they be all as uniform as possible in size and size for the column being used.. the important of the rocks being uniform is that you want the smallest open space between then went packed, also when packing lava rocks, they need to be shaken/juggle as they are loaded in the column, so as they can reduce the open space.. I've used rice to pea size rocks on a 2" with great results, but prefer a little bigger only because of ease in cleaning them after a run..

As to the rock dust, that is cause by not cleaning them properly before use.. once sized the rocks need to be shaken to remove all the sharp edges, as that what will fall down into the boiler.. I clean new rock sets by shaking them in 1 gal coffee can with water in it over many session until hardly any dust/particles comes out, then they are ready to be put in use..

As to your 4" column, if it was I, I would use 3/8 -9/16" size.. the sizes you mention are still too large in my experience.. the smaller the space between them the better they where, within reason, as there is still a need for the vapor and distillate to move up and down during the refluxing action..

Mars

[OtisT]

As to your 4" column, if it was I, I would use 3/8 -9/16" size.. the sizes you mention are still too large in my experience.. the smaller the space between them the better they where, within reason, as there is still a need for the vapor and distillate to move up and down during the refluxing action..

Mars

Hey Mars. This is a another case for switching to the metric system. The size of rock you recommend for my 4” is exactly what I just said I was going to use in my 4”. The 3/8”-9/16 size you recommended is in-between the 1/2” and 1/4” screen sizes I used to grade my rock. (Unless I misread your post or did my math incorrectly.). Regardless, I always appreciate and value your input.

Thanks. Otis

[bluefish_dist]

Don’t that this as attacking your results. They are good as you have comparison numbers, but don’t get too wrapped up on your actual abv. The hydrometer you are using is highly suspect on how close it is to actual abv. The one I had like that was 3 abv off. If you want an exact reading, you need to be using a high accuracy one, for 180-200 proof and maybe even a calibrated version if you want to be better than .1 proof. You will also need a precise thermometer as well.

I am curious to see what you find on lava hetp. I was never able to get my spp to run even as well as stainless scrubbies and after what I paid for it gave up and just went taller and larger diameter on the column instead.

[bunny]

I was never able to get my spp to run even as well as stainless scrubbies and after what I paid for it gave up and just went taller and larger diameter on the column instead.

Do you possibly still have those spp?

If so, would you consider selling them?

[bluefish_dist]

I was never able to get my spp to run even as well as stainless scrubbies and after what I paid for it gave up and just went taller and larger diameter on the column instead.

Do you possibly still have those spp?

If so, would you consider selling them?

Sold it a long time ago.

[bunny]

I was never able to get my spp to run even as well as stainless scrubbies and after what I paid for it gave up and just went taller and larger diameter on the column instead.

Do you possibly still have those spp?

If so, would you consider selling them?

Sold it a long time ago.

Thanks,

[bitter]

I was never able to get my spp to run even as well as stainless scrubbies and after what I paid for it gave up and just went taller and larger diameter on the column instead.

Do you possibly still have those spp?

If so, would you consider selling them?

Sold it a long time ago.

Thanks,

There is a guy in New Zealand that makes and sells spp.

Look for the stillit spp video has link to seller.

A buddy made mine and I cut it manually. He is working on cutting and after that will determine if he is going to start selling some. I have 6 liters finished for my setup. Washed and cleaned this weekend and do cleaning sac run with it really soon.

B

[Northsouth]

Don’t that this as attacking your results. They are good as you have comparison numbers, but don’t get too wrapped up on your actual abv. The hydrometer you are using is highly suspect on how close it is to actual abv. The one I had like that was 3 abv off. If you want an exact reading, you need to be using a high accuracy one, for 180-200 proof and maybe even a calibrated version if you want to be better than .1 proof. You will also need a precise thermometer as well.

I am curious to see what you find on lava hetp. I was never able to get my spp to run even as well as stainless scrubbies and after what I paid for it gave up and just went taller and larger diameter on the column instead.

I just got the cheap stuff from Amazon, so it might be way off. But in comparison of the 3, it gives the same error. It is a set of 3 actually, 0-40, 40-70 and 70 to 100, which is the one I used. The advantage is that at least there is more space between the lines, so the error caused by surface tension (liquid sticking to a vertical surface) is less.

[bluefish_dist]

I just got the cheap stuff from Amazon, so it might be way off. But in comparison of the 3, it gives the same error. It is a set of 3 actually, 0-40, 40-70 and 70 to 100, which is the one I used. The advantage is that at least there is more space between the lines, so the error caused by surface tension (liquid sticking to a vertical surface) is less.

You are correct, good data to compare the different packing materials. My point was, don’t sweat the actual number as it may not be correct anyway. If it’s clean and drinkable, it’s good enough.

[Northsouth]

By the way, here is my current Vodka maker. Starting from bottom:

1. Borasilic glass 350mm 3", now with 5-6 mm SPP held up by pressed in copper mesh (a bit risky, but holding so far).
2. First reducer with SS packing. This creates lower pressure/higher speed at the neck, hence some extra condensation/reflux.
3. 2nd and 3rd reducer, SS scrub at bottom, some cut copper 1/4" pipe (rashing) I had laying around in a jar (about 100 mm height). Then filled with SS to neck.
4. The previously used stripping column 500 mm. SS scrub at top/bottom, 5-6 mm SPP in middle.

In addition, I also put together a 1200mm 2" column, 2 glass bubble plated and a 2" dephlag, and little by little, all this will be tested in various combinations.

In the shown setup with Lava Rock (also in the middle though), ABV was steady at 95.1-95.6 throughout the whole run. With SPP, I have to admit that it was difficult to run it above 95 ABV, wash being low wine diluted down to below 15-20 ABV. Will have to repeat the test with more consistent readings, write down data, etc. and also fill the middle with SPP. My suspicion is that SPP at this size need much more power (only have 3000 W) and reflux, perhaps I have to run it in CM mode, where I can crank up the cooling much more.

If anyone has a view/feel for that, I would really appreciate the input.

[bunny]

If anyone has a view/feel for that, I would really appreciate the input.

I congratulate you on your ambition to compare Lava Rock vs SPP vs Stainless Scrubbers!

However at this time I don't see any usable or transferable data from your testing.

I suggest you start by determining the HETP of each of YOUR samples using odin's methods.
viewtopic.php?f=1&t=63103#p7431465

A tip to make it simpler: Make you 10% boiler wash from hearts and water and not low wines.
This way you won't have to deal with sub azeo temps at the take-off.

****don't trust any reading from a parrot-

[Northsouth]

If anyone has a view/feel for that, I would really appreciate the input.

I congratulate you on your ambition to compare Lava Rock vs SPP vs Stainless Scrubbers!

However at this time I don't see any usable or transferable data from your testing.

I suggest you start by determining the HETP of each of YOUR samples using odin's methods.
viewtopic.php?f=1&t=63103#p7431465

A tip to make it simpler: Make you 10% boiler wash from hearts and water and not low wines.
This way you won't have to deal with sub azeo temps at the take-off.

****don't trust any reading from a parrot-

Yep, I was aware of the 13 re-distillations to reach azeo, but if I can't get beyond 95.6, it is not going to work, I'm afraid. It could b the equipment is inadequate as someone already pointed out here. In theory, I should have at least 20 plates in the setup in the photo above.

[bluefish_dist]

The hetp of ss scrubbies is about 4”or 100mm, that makes a 20 plate equivalent 80” or 2 meters of packing. I think the setup in the picture is quite a bit below that height. The data suggests lava and spp have taller hetp, needing more height to achieve 20 plates.

[Northsouth]

The hetp of ss scrubbies is about 4”or 100mm, that makes a 20 plate equivalent 80” or 2 meters of packing. I think the setup in the picture is quite a bit below that height. The data suggests lava and spp have taller hetp, needing more height to achieve 20 plates.

That is correct, this is what this test indicate. Which was surprising to me since SPP should be HEPT 1/3 of SS scrubbies. That should bring me to the promised land with a 1.2 m column, but not so, it seems.

It could be the way I ran it, it could be that the homemade SPP is too big, too thick wire, etc. It is 5-6 mm, 7-9 mm length 0.8 mm wire. Maybe too round at the edges? Don't know.

Have used above setup before with lava rock. (they are rightly sized for both 2" and 3", just not nicely shaped, but some bigger ones snuck in on top and bombed the photo session).

So today I did a 15 abv low wine run (diluted product from the above test) with SPP. Lava rock actually outperforms this particular SPP with respect to abv.

Why do I even care if it is 95.3 or 96.2? It is about having that skill in the toolbox on my quest for the perfect Vodka.

[bluefish_dist]

I had the same issue with spp that I bought. I could not get it better than scrubbies. Gave up and just went taller and larger diameter. I never tried lava rocks as I had concerns of what might be in it and leach out. As a commercial distiller, I wasn’t going to take that risk. When I tried marbles, I bough lab grade soda glass marbles, not hobby lobby China marbles for the same reason.

I also tried structured packing which is cool stuff and advertises a hetp that is good. Never could get it to run better than scrubbies. While many say they can run vodka proofs, ie 190+, I found it quite hard to do so consistently and quickly. I think my best run was on 8 ft of packed 4” over a 6” bubble plate and made a consistent 190.5 from low wines.

[Bushman]

I believe Mash Rookie did a whole thread comparing different packings. He was very good at testing and documenting his results. You might do a search, shouldn’t be hard to find.

[bitter]

I believe Mash Rookie did a whole thread comparing different packings. He was very good at testing and documenting his results. You might do a search, shouldn’t be hard to find.

This one I think viewtopic.php?t=30727 ?

[Bushman]

I believe Mash Rookie did a whole thread comparing different packings. He was very good at testing and documenting his results. You might do a search, shouldn’t be hard to find.

This one I think viewtopic.php?t=30727 ?

That is the one I was thinking of.

[bitter]

Also I think with anything SPP is like a racecar.. it may take time to learn to drive it to its optimal while putting out higher volumes. Its a balance between input power, condenser capability and also power applied. Getting the right fluidized bed but not flooding is a fine line and finding out were this is is going to be different with different setups.

Also the Russian guys say you need your column insulated also. Odin mentioned runny crazy speeds with his 2" over 4LPH but also mentioned with was with a more open designed SPP. DAD300 showed using different sized SPP in different column sized 5x5 is too large for a 2" column still works but not optimal. Sounds like size matters.. Sounds like 3.5x3.5MM is what is recommended upto abotu 4.5mm SPP for a 2" and a 3" 4.5mm would work but depending on your power. You look at dr gradas they use 3.5x3.5 but max like 2.5 to 3kw of power and do like 2.5 LPH at lesat what they advertise I think from memory go check.. I suspect this is what anyone can do and you can squeek a bit more out of it but will be tricky to find the right balance and not flood the column....

Since I have a 3" and want to run well and also go fast went with about 6mm SPP. It may not hit 97.2 unless run slows but should if I have enough power run faster. Based on Odin's numbers I expect 3.5 LPH and could hit 5.5 LPH but thats all theory and is out SPP perfect design no idea our first time making so may be less than optimal... Time and testing to follow.... according to the 1/10 to 1/12 of column diameter our SPP should be max 7.7mm and about 6.5mm we are slightly smaller as only 5500W currently for power. We will see normally do 94 to 95% from current setup (40% charge) with copper blocker packing and 3.5 LPH so I feel with SPP should be able to get a bit more but have to max to 30% boiler charge based on Odin's many comments on column blockage with higher % in boiler.

to me SPP is about most clean I can get and still a good speed and maybe not have to strip and then do big run. If SPP from 10% wash can get me to a good yield and clean product that will save time. I have to run much slower than 3.5 LPH with copper blocker packing when only 10% charge and also fiddle all the way though to keep things balanced my hop is SPP can set it and forget maybe some small adjustments near the end to slpw down takoff and increase reflux... These are my hopes testing comming soon.

B