Thumper Problems

[Almanac]

I first posted details about my Thumper in Jul 2012 under the Topic "New Pot Up and Running" in this section for anyone who wants to look back and see the details of the build.

This is my 6lt Thumper that I run on my 50lt keg boiler on Spirit Runs..


The other day I had a Spirit run going and all was normal, kindof or so I thought

Distillate got down to 40% and still no sign of Tails. (I didn't have a cold or other problem with my nose) To check I wasn't imagining things I went to my Tails jar and opened the lid...unmistakable aroma.

I cut off the Spirit collection at that point and even the next day the distillate that was collected at 40% was clean and neutral. OK, that was odd enough but when I was dismantling the Still for after-run cleaning I opened the Thumper and found this...
(Click for big pic)


on closer inspection I found this...



...it looks like CUSO4 or Copper Sulphate but where did it come from? I've been running this setup for about 6 months and have never had these deposits, or anything like it, in the Thumper before.

Also, can you see the liquid level!!! What's that all about? When the boiler was nearing distillation temp, I put the Thumper inline with 3lt of boiling water so that the distillate vapour from the main boiler wouldn't have to heat the liquid in the Thumper before delivering product to the condenser. It was about half full but, as you can see, by the end the run it was almost full to the lid

The only difference in the run was that I was using my 2Kw element and during the heads collection I ran it at 600w and once into the Hearts I still kept the power down around 800w for a long slow run.

BTW, the black trace on the Thumper wall below the CUSO4 isn't supposed to be there either...no idea what that is and it wasn't there at the start of the run!

Never a dull moment

AM

[Capt-Cudellez]

Not seen that before, but if your rig has been sitting a while could it just be oxidation being cleaned off the inside of the pipes and being left in the thump?

What were you running, any idea if it was more acidic or base than usual? I've heard of alkali washes leaving the spent wash pink from it eating the copper, and you know how we'll hot acidic stuff cleans up copper.

I wouldn't be too worried - really confused by the ABV though? but I don't pot still neutral.

I have had stripps that smelled and tasted okay all the way down, I just think that's when you get a really good clean ferment, hasn't happen all that often to be fair

[scarecrow]

This is my 6lt Thumper that I run on my 50lt keg boiler on Spirit Runs..

I used to run a 6 litre thumper on a 20 litre stove top still. If I ran it too hard it would fill the thumper and just puke the wash straight through. General rule of thumb is thumper to be 1/4 to 1/2 the volume of the pot. This is for safety sake just in case of a puke.

This was my thumper.

I had to double the number of holes to make it work efficiently. The ring sat almost on the bottom. I would only put enough wash in to cover the ring. (about 300ml). Any more than that will cause problems. Wash will give you more flavour than water. There is no need to boil it first.
I don't know the design of your thumper, so I can't offer you advice there.

The other day I had a Spirit run going....

What did you put through the pottie this time?

Distillate got down to 40% and still no sign of Tails.

That is really odd. At 50-55% you would start to smell tails coming through. At 40% it should be rank with a cloudy appearance.

but when I was dismantling the Still for after-run cleaning I opened the Thumper and found this...

The green and black is from an acidic wash. Depending on the acid it will give a different colour.Sulphuric acid generally produces copper oxide (black muck)
I used to get a blue tinge in some of my runs.

If you leave the wash in the thumper (ie don't flush it out properly), you get this:

I've been running this setup for about 6 months and have never had these deposits, or anything like it, in the Thumper before.

It builds up. Give it a good clean with vinegar and then a good flush with clean water. Also, check the pH of the wash in the thumper when you are finished.
I never leave my still wet. It gets a "blow dry" with compressed air after every run. Try adding some copper shards to the boiler. If you are adding pennies, check what they are made from. Copper coins made before 1992 are 97% copper. After that they are copper coated steel.

Also, can you see the liquid level!!! What's that all about? When the boiler was nearing distillation temp, I put the Thumper inline with 3lt of boiling water so that the distillate vapour from the main boiler wouldn't have to heat the liquid in the Thumper before delivering product to the condenser. It was about half full but, as you can see, by the end the run it was almost full to the lid

Like I said above. Too much liquid in the thumper to start with.
I started with 300ml and I would have anywhere between 3-5 litres in the thumper when finished.
Again, I don't know the internals of your thumper. If all you have is a single pipe emptying into the thumper, you will be in trouble. The thumper arrangement is meant to be like a perforated plate still, lots of little holes to create lots of little bubbles and in turn creating a large surface area for heat transfer.
You have no head room with such a big pottie and small thumper.

Hope this helps

scarecrow

[Almanac]

The wash was to make some neutral and was made with 2 X Vodka Star in a 50lt wash with 11Kg of sugar. This was my first proper wash after the still being laid up for three months. Before running the VS I ran 40lt of 10%ABV junkahol and disposed of the distillate. After that run I washed everything through but didn't use vinegar or citric acid.

The VS wash finished at 0.988 and the strip was unremarkable. I collected 16lt of low wines at an average 52%.

For the Spirit run I diluted the low wines to 20% with 25.5lt of clean filtered water. I didn't check the pH of the overall charge but the 25.5lt of water had a pH of 7.0 and I would guess the low wines would have been somewhere in the region of pH 3 and this would put the overall pH in the area of 5 - 5.5 at a rough guess.

This is the vapour distribution head in my Thumper...

...and the two pipe access holes in the lid are sealed with locking nuts on the outside with silicone O-ring seals.

I've used this configuration for about 12 Spirit Runs since last July and despite initial concerns that flooding could be a problem given the relatively small size of the Thumper, it never happened. I raised this very question under the topic "Build Your Own" in a thread called "New Pot Up and Running".

In fact, last Aug, just to prove it to myself, I measured the liquid left in the Thumper after a full Spirit Run and it was approx 3.6lt from a 3lt start but that run was done at full power.

I'm going to set up a dummy run with just water in the boiler and Thumper and do one run at full power - 2Kw - and a second run at just 800w as I did on this run. I'll let you know what the outcome is

Thanks for all the input SC. I take your point about the tails but this was a double distillation so the entire charge is crystal clear. However, I have no explanation for the absence of tails at 40% and the distillate is very drinkable even though my minimum cut for neutral is 55% and more usually 65% so the rest will be consigned to the tails jar anyway. It has me completely puggled

Capt C; thanks for your input too. You'll remember we discussed this problem last year and you were able to help me understand the physics involved and that,s the way it,s been since...until now

Did I mention that there was only the faintest smell of Tails when I turned off the still altogether and the last of the distillate for the Tails Jar was measuring 20% - go figure!

AM

[scarecrow]

The first thing I would do is run low wines in the thumper. If you are making neutrals, don't use wash, as the flavour will carry over. No need to dilute. Volume should be just enough to cover the outlet tube. The less volume, the less energy required to raise the temperature.
If you use only water, the thumper will hang on to the alcohol until it reaches a high proof, then start to release it. It may flood the thumper.

Second thing to do is run the pottie a bit harder. The product entering the thumper is doing so too slow (not transferring enough energy). It is filling the thumper faster than it can heat it and start the release of alcohol. (Proven by the high tide line)

Thumpers were originally used to contain the overflow (puke) from a still that was run too hard (wood fired and hard to control). They then found that the output (ABV%) was higher than a straight single run, BUT, had lots of flavour carried through by the puke in the thumper.

Just as a side note, My thumper inlet tube had 100 holes. I doubled that to 200 and the performance improved dramatically.

It is considered more efficient to double distill rather than running once with a thumper. In saying that, three passes through a thumper set up should get you close to 93% and produce a nice clean tipple.

Also remember that the higher the starting ABV% in your pottie, the more your thumper will fill.
Also, running wash in the thumper pushes tails into the condenser (hence flavour). Running heads and tails gets you high abv to start with but also more heads and tails in the finished product.

scarecrow

[Almanac]

Thanks SC that all makes a lot of sense and I'm going to make a number of changes to my thumper and what I put in it. Obviously the idea of running the pot low and slow didn't work except for the tails angle - at least that's what I think happened.

Generally I don't bother using the thumper on the strip.

I really have to get back to running my VM column for neutral spirit.

AM