experiment stuff

[rkr]

A couple months ago I posted an outline of an experiment that would prove if any given material (plastic in this case) in the vapor stream added anything to the distillate.

Would somebody with the means just step up and perform it already!

This kind of posting just divides everybody and provides no solutions.

Rez

Can you repost it in here? I agree that we won't get anywhere unless someone does some real testing. The problem is that most of us do not have the gear to do it properly.

We need to remember that resistance to ethyl acetate and propyl compounds should also be tested as they are present during distillation process. Maybe methanol and butyl compounds as well although their amount is quite low. Actually based on my inadequate tests I'd say that it's either hot propanol or butanol that causes problems with some PP brands.

Cheers, Riku

[rezaxis]

Well, here it is. I hope someone can make it happen. The whole thread it came from is called "stirring the pot..." in the research and theory section.

The chromatography is the hard part, but as it has always been for me in my working career, the theft of time and equipment while at work has always been possible. I never done it... honest!

I suspect there are at least a few people here that have access to this equipment, and have the time to make the experiment happen. Maybe I'm wrong... Maybe those folks are just afraid to be the messenger of the results, or question their abilities to perform the experiment, or maybe they already know the results.

1. Take 1 part of neutral spirit or anhydrous ethyl alcohol and mix it with 4 parts of well boiled deionized water giving a 20% concentration of alcohol, making a simulated wash that is essentially water and ethyl alcohol.

2. Profile the simulated wash with the appropriate chromatograph.

2. Strip it collecting everything, though a well used but very clean still with no plastic parts, or a distillation assembly made entirely of glass.

4. Put the simulated wash back together.

2. Profile the reconstructed wash with the chromatograph.

If it's the same then a good baseline has been created and proving that the still added nothing.
If the still added anything, it would show up in the new profile and could be eliminated from the next part of the experiment.

5. Put a big sample with a lot of surface area of the suspected plastic material (PTFE) in the vapor path at the highest point in the still.

6. Re-strip the reconstructed wash.

7. Put the simulated wash back together.

8. Profile the reconstructed wash with the chromatograph again.

If the plastic did or did not add anything compared to the previous profiles you would know it and this debate, at least as it concerns PTFE, could end. Teflon either is a good or a bad thing. The tester would also know if his still is adding anything to his runs.

Rez

[rkr]

I see three problems with your approach. With non column still 95.6% alcohol content is never reached. The plastic should be at the column wall to allow reflux to run over it as well. If it's only suspended in vapor path it may not have liquid contact. Having the plastic at the top could mean that higher boiling point alcohols won't reach it. I'd also like to see long time exposure, not just a quick stripping run.

Cheers, Riku

[rezaxis]

Well then I guess it won't work. I'm no expert, so I'm not arguing with anybody. Maybe, the experiment could be refined? I'm sure there are more qualified people here who could do that. I'm not sure if any experiment could be outlined that would satisfy everyone though. Dreamin' I guess.

Rez... needs a drink.

[Husker]

I think your methods would work. However, you would want to test several situations for each type of material using:

Materials:

- 100% stainless (assume as baseline, or possibly glass would be needed).
- Copper (copper column, copper packing, copper condensor).
- Different non-standard componenets (PP, PTFE, ...)

Locations for the material (NOTE not all material can be used for a location)

- Boiler
- Column
- Packing
- Condensor coil
- Take off / reflux tubing
- Connections / gaskets / sealants
- Storage container.

As you can see, to do a "real" test, there is a lot involved. It is possible that PP could be used successfully as a boiler, but nowhere else. Possibly PTFE is OK for any cooled distillate of any strength, but should not be in the high vapor path, or in the reflux stream. (NOTE I really do not know, just making hypothesis)

A test like this "could" be done, but it is pretty intensive. I am sure that a distillery "might" undertake something like this, however, for the cost and time involved in this, it would probably become proprietary trade secrets for that company. The test could take 7 or more distillations per each type of material, along with the associated time at a mass spectrometer (or other chemical measuring device).

NOTE that Chemist has already stated within this thread, that EVERY time he has tested high proof in plastics that :

In the course of my work, I've seen many, many plastic bottles with high proof spirits in them. Sent to me by the distillers. I have yet to find one sample that didn't contain detectable amounts of plasticizer. How much di-iso-octyl phthalate do YOU want to eat?

(I certainly don't mean to be argumentative on this most merry of days: I'm just strongly advising against the use of plastics where, in my opinion, they don't belong.)

H.

[rezaxis]

I've had a few, so I feel like responding...

The sample material I imagined at the beginning would be virgin PTFE turnings or shavings as might be produced while drilling or turning on a lathe. Lots of surface area. Not a lot of little pieces, or some big chunk.

Riku, I think putting the sample material under the reflux return in a valved reflux, replacing the second roll of mesh from the top would meet the high temp/high ABV vapor and the high ABV/high temp liquid contact requirements. Running in 100% reflux should certainly allow any length of contact you might choose.

I use SS sink screens to hold my copper mesh inside my column. I imagine they could be used here to hold the sample material anywhere inside the column you might choose. Packing the area with the turnings would allow good vapor contact and plenty of liquid contact all the way to the sides. I see a gin basket in my future...

Husker, an exhaustive repetitive testing of every type of material, in every location possible in every type of still imaginable would provide a comprehensive analysis for sure. My original thoughts were only to provide a test that placed the highest order of plastic in the harshest possible environment, assuming that if a material failed in the harshest environment it shouldn't be used anywhere else either. And if virgin PTFE failed all lesser plastics would have to follow, and could be assumed to have failed without testing. Of course if virgin PTFE did not fail, it would only prove that virgin PTFE was OK to use in any environment as severe or less, and all other materials were still suspect.

Barkeep! ...another.

Rez

[rkr]

Good thinking rez. Testing the sample at the top and bottom of the column while running it at full reflux would be enough and could be done simultaneously. I'd like to see separate test performed for 20% mash and sample suspended in the mash in boiler should the first test fail as the boiler is entirely different environment for operation.

So far the only useful plastics worth considering seem to be polypropylene, RTV aquarium type silicone and PTFE/teflon. HDPE won't stand the temperature associated and other plastics are either rare/expensive or known to be non alcohol tolerant.

About those tests performed by chemist, he didn't mention what material was used for those containers. As an example I've had some thin wall PET bottles to deform while trying to store low wines in them. Still, whiskey is sold in plastic bottles so I would assume they are not made from PET but some other material. I actually checked one of those plastic whiskey bottles but could only find mark UCP which I couldn't connect to any plastic brand.

Cheers, Riku

[rezaxis]

Somehow, I'm thinking this thread has gotten highjacked...by ME! That wasn't my intention. Mods, could you move this experiment stuff to the "Stirring the pot" thread in the Research and Theory section? Thanks.

Rez

[rezaxis]

Thanks for moving this experiment stuff out of that other thread.

Is it hot in here? or is it just me?

Rez

[hornedrhodent]

Haven't seen anyone putting up their hand to do the gas chromatograph work - sorry I haven't got acess to one either!

[rezaxis]

Yeah, I don't think it's gonna happen... I tried.

[rkr]

It's easy to be an expert when no one has facts. I hope we can get them one, not just repeat old rumors over and over again.

Cheers, Riku

[rezaxis]

I thought this was funny. Sometimes it's just not worth talking about a subject anymore. Maybe this is one of those subjects.

Rez

[mtnwalker2]

Is that horse dead, or have you hit it yet

Sometimes you have to use a 2 X 4 to get their attention