Report on leeching of plastics into ethanol

[seravitae]

Chemical migration from silicones used in connection with food-contact materials and articles

This project was carried out to provide detailed information on the types and composition of silicone based products that are used in contact with food and identify the extent to which migration of specific constituents into food could occur. The project builds on information previously obtained on elastomeric silicone food contact materials such as seals and tubing.

http://www.foodbase.org.uk/admintools/r ... _03_05.pdf

[theholymackerel]

Thankyou for postin' this study. It's interestin', and mostly good info.

I saw a few problems: Like on page 146 and 144 of the study where they said it's likely that there are vinyl groups in the mix also, but the limitations of the study don't allow for measurements. Also on page 147 it spoke of calcium, aluminum, magnesium, and silicones bein' detected... where the hell did the calcium, aluminum, and magnesium come from???!!!

I fully admit that alot of this study was beyond me. I'd love for The Chemist (and anyone else with a grip on what was bein' said in this study) to pipe in and make all this more clear.

Pages 149 and 150 show that different types of silicone leach 4.3 to 14 times more silicone(?) into solution usin' ethanol at 60 deg C and 4 hrs vrs distilled water at 4 hrs and "reflux temperature". What does that mean? 100 deg C at one atmosphere? 30 deg C under vacuum? Who knows?

On page 143 they explain that the levels detected exceeded the possible limits of the experiment with the ethanol extraction, and went on to say that the result depends on the experimental conditions and that their conditions were "extreme use conditions". 60 C for 4 hrs for 95% abv ethanol is "extreme use"? No way! Double (or triple) the time and add an extra 1/3 of the heat and yer approachin' our conditions.

I suspect that findin' a study that will be directly applicable to us will be quite hard to find. It might even take a real effort on our part, and a small expenditure of funds to get a study done that will directly address our questions and expand our list of good materials. Somethin' we as a group should consider...







Once again I wanna state that I don't understand all that is bein' said in this report. I'd love for a chemist in the alcohol industry to take a look at this and let us know how good the info is and how it applies to us. I'd also like a medical doctor to take a look at this study, especially the substances detected, and their levels. Are they anythin' to worry about, or not? We'd all like to know.







So...thanks for postin' this study. We have asked for years for folks to post studies directly linkin' plastics, and their effect upon ethanol. This is one, and it might be good. Thanks for postin' it, but I'm confused by yer aggression twords the mods.

[seravitae]

Hey mate,

Elements are often detected in plastics due to the formation processess. Also, you tend to find heavy metals like platinum from catalysts. And also from water used int he experiments and can influence results.

Reflux temperature means the temperature required to reflux the solution at atmospheric pressure, so reflux temperature corresponds to between 78-100C depending on the ratio of ethanol. So at 95% ethanol it's gonna be close to 80C probably.

Also, the conditions are 'extreme' by their standards as they aren't writing this for distillation - they are testing the plastics for food storage. As temperature goes up, so does reaction rate (doubles roughly every 10C) and solubility goes up. This report is indicative of storing 95% ethanol in bottles stored in the sun, or in a hot car or something... Not so much for distillation, but the results are still useful nonetheless.

Although I'm not in the alcohol field, I am a chemist, so yeah. I'll try to provide insight where I can. Basically they are saying that storing 95% ethanol is presence of silicone (even food grade) causes the threshold of leeched chemicals to be greater than 10mg/dm^2. So, silicone, for storage, for seals (ie making a bulkhead with a silicone gasket) for a still is not a good idea.

Mod comments was removed. I've rejoined this forum after posting scientific data like this was frowned upon, blocked and generally caused a shi*tstorm and I feel I was unfairly targeted by lesser educated mods. Nothing personal. Hopefully the chip on my shoulder will be smoothed soon if scientific data such as this is tolerated and discussed openly.

[theholymackerel]

Mod comments was removed. I've rejoined this forum after posting scientific data like this was frowned upon, blocked and generally caused a shi*tstorm and I feel I was unfairly targeted by lesser educated mods. Nothing personal. Hopefully the chip on my shoulder will be smoothed soon if scientific data such as this is tolerated and discussed openly.

Sorry about the comment...I spent more than an hour readin' and skimmin' and missed you removin' the comment.

We have been tryin' to discuss openly and calmly these subjects... comments attackin' mods who donate free time to the site doesn't help the discussion or foster the open attitude we all want here.

Anyhoo...thanks for postin' the link. And I'd like The Chemist to chime in here please, and if anyone can get a medical doctor to read this study and and post his/her thoughts it would be awsome.




As always this thread will be left alone right up until someone loses it and cusses us all out. So I beg ya'll... please, lets be tolerant of each other and try to keep this thread businesslike.

[HookLine]

Good info, seravitae. Exactly the sort of thing we need to have on the table in this discussion.

Thanks.

[Hawke]

If I understood one part in there, it did seem to say that the leaching was neglagable or non existant under 70%? Pretty tough read for this highschool chemistry educated stiller. The part that was interesting to me was the formation of formaldahyde as part of the catalyst breakdown.

[scarecrow]

Just started reading the article.

It has always concerned me about the use of silicones in food grade applications, as well as plastics.

I remember back in the early 80's we were trying to develop a non stick coating. We ended up using a silicone crosslinking resin and polytetraflouroethylene (PTFE or Teflon).
Silicones are used because they withstand very high temperatures and don't (supposedly) degrade. We used to make high temp paints for boilers that withstood 600C.

Silicone resins and oils are used in hair shampoos and hand creams. They make it feel silky and smooth.
I once made a steering wheel coating for The Ford Motor Company based on silicone and Teflon that passed 1000 rub cycles. It only had to pass 50. It sure is slippery stuff

But, I still wonder what detrimental effect silicones and teflon have to the human body.

I remember having to remove certain phthalate plasticisers from coatings supplied to Chrysler and GM because they were toxic at elevated temperatures. Does anyone remember the hazy film on the inside of your car's windscreen when you left it it the scorching sun all day. You had to wipe it off just to see out. This was the toxic plasticiser coming out of all your vinyl seats, dash, trim, radio etc etc. And why Armorall is now making a fortune putting it back in with something less toxic.

I was always told to put hot solvents eg ethanol etc into stainless steel or glass containers to avoid contaminating and possibly voiding any analytical data.

Just the fact that it is hot ethanol is a concern. But to let it come in contact with anything, ANYTHING plastic worries me. If you want something to dissolve quicker in a volatile liquid, heat it up. You would be surprised what won't dissolve at 25C but will at 90C.

Anyway, back to my reading. That's my $0.02 worth.

scarecrow

[schnell]

It's a typical analytical chemistry report. They describe the trace level analysis of compounds derived from silicones, which are mostly variants of siloxanes. This report pretty much shows why silicones are safe for food. Look at what they got out and how much. The paper is all about what quantities of what substances can be expected.

(By the way do not confuse siloxanes for phthalates.)

One critical point I'd make:
with the GC/MS using a DB-5 column you tend to see lots of peaks in discreet increasing steps on your chromatogram. Especially as the column gets worn out. Guess what those peaks are?

Yep, chromatography columns are made out of siloxanes. As they get old and abused you see more and more siloxanes in your chromatograms. I've seen lots of amateur chromatographers mistakenly report "siloxanes" in samples that were perfectly clean, when their instrument actually needed maintenance. My point is that quantitating could be a little challenging, with some unexpected surprises.

I don't think this report lends much to be applied to this hobby. Interesting in its own way perhaps, and essential if I was a food chemist, but not much we can appy to our efforts here.

I still advocate a no plastic rule-of-thumb, even though I have silicone and teflon bits on some of my commercial tools. I've destroyed more than a few pieces of plastic labware with high proof ethanol, so now I just try keep them away from each other.

[schnell]

by the way a rule-ofthumb is not a law-of-nature...

there are exceptions to every rule. recognizing when they are appropriate comes with experience, learning, and having some handy documentation of the sort Seravitae has shared with us here.

[theholymackerel]

Thanks for pitchin' in and givin' us some info Schnell.

I'm sorry to hear that this study isn't useful to us in the home distillation hobby. :-(

I agree that keepin' high strength ethanol away from plastics is a good rule of thumb. I also agree with you that there are probably exceptions. The Chemist helped us to understand that teflon was probably safe and might be a good material for gaskets.

But I don't quite understand if yer sayin' silicone is ok, or not ok for our purposes. I know there are different ways to "cure" silicone, and some of them use really nasty chems. Can you please provide us with any more info on silicone? Would one type of silicone be ok, and another (or others not be ok)? What do you use silicone for in yer stills? Flexible, permanent seals? Do you feel like they are a safe alternative? Please pitch in anymore info you have.

These "siloxanes" that leach outta silicone, are they possibly harmful if ingested? Anyone out there with a chemical and medical background that could help us with understandin'?

[seravitae]

I think this is relevant to home brewers.. Too often have i heard the comments here "we dont like plastics because 99% of reports show what the ethanol does to the plastic, not what the plastic does to the ethanol..." - and here's a report showing just that.

Schnell - Of course, quantiating can be tricky but that said, one shouldn't be quantitating with mass spectrometry anyways (even though it usually works), since it's not strictly a quantiative method due to possibilities of preferential ionisation of selected species in the sample.

And yes, since colums are often made from siloxanes, you can get contamination with poorly maintained equipment, but somehow based on the quality of the document and the company's image i don't think it's a case of an ameteur chemist misreporting a dodgy MS...

[schnell]

I have silicone seals in my sight glasses and I have silicone seals in my wine topping vessels. It's food safe. That's why it's used in food handling equipment.

Will it leach components? Yes. That's what this paper was all about. It even nicely described them.

one shouldn't be quantitating with mass spectrometry anyways

that's a ridiculous claim.

I didn't intend to call the authors amateurs. But I have seen plenty of siloxane peaks on thousands of chromatograms using DB-5 columns. It came to mind when looking over their methods, especially since this is what they were measuring.

I don't think this is irrelavent because they don't know what they're doing. I just don't think it's going to be useful to our hobby.

[schnell]

These "siloxanes" that leach outta silicone, are they possibly harmful if ingested?

not really. they aren't very toxic as a chemical class.

silicone is the common name of a polysiloxane polymer, (R2SiO)n, thats why the leachates are various sizes based on the n value. this is why you see discreet stepwise peaks at regularly increasing retention times in their results, indicating the addition of more n units. they can be linear or cyclic. differences in the R groups give you the different brands and varieties of commercial silicones.

[stillvodka]

This Below is just one example , do searches , you can go on finding well justified negative reports where plastic is concerned, and these are just related to every day food and water/liquid be stored in these containers made from Plastic, the most shocking bit of the report below is regarding the Use of BABY FEEDERS leaching chemicals just heating milk up , God know what happens when people use plastic in their stills with hot ethanol, Plastic / silicone's / is a no no for me now, it just cannot be trusted, it's may not be the plastic, it's what they have put in the plastic
I will say though that tTeflon is a different animal altogether



Gender bending chemicals in food packaging, drink cans and baby bottles may double the risk of heart disease, researchers have found.

They have shown that people with higher than normal levels of bisphenol A (BPA) in their blood are more likely to suffer from heart problems.

The chemical also appears to raise the risk of diabetes, the study of nearly 1,500 people has shown.

BPA is used to make linings of food and drink cans. It is also found in plastic bottles, CD cases, plastic knives and forks and dental sealants.

It is the first time it has been directly linked to health problems in humans and raises disturbing questions about one of the most common - and controversial - chemicals in everyday use.

Although some animal studies have suggested that it is safe, others have raised serious concerns.

BPA, which mimics the female sex hormone oestrogen, has been linked in animals to breast cancer, liver damage, obesity, diabetes, fertility problems in males and developmental disorders in the young.

Professor David Melzer, of the Peninsula Medical School, Exeter, who led the research, said: 'Our study has revealed for the first time an association between raised BPA loads and two common diseases in adults.

At the moment we can't be absolutely sure that BPA is the direct cause of the extra cases of heart disease and diabetes - if it is, some causes of these serious conditions could prevented by reducing BPA exposure.'

The study, published today in the Journal of the American Medical Association, looked at blood and urine samples of 1,455 adults aged between 18 and 74 years.
Enlarge grapic


The levels of BPA in the study were well below official safety standards, but the 25 per cent of people with the highest levels of BPA were twice as likely to suffer heart disease or diabetes than the bottom 25 per cent.

Higher levels were also linked to abnormal concentrations of liver enzymes, a possible sign of liver damage. The links were strongest for young people.

The scientists do not know how BPA could increase the risk of heart disease and diabetes.

However, the chemical could lead to more fat being laid down in the arteries and interfere with the way insulin is processed.

Other researchers urged caution. Professor Richard Sharpe, of the Medical Research Council Human Reproductive Sciences Unit, University of Edinburgh, said: 'There may be a more commonsense explanation.

'That is, that if you drink lots of high-sugar canned drinks you will over time increase your risk of cardiovascular diseases and diabetes - I think we already suspect this - and incidentally you will be exposed to more bisphenol A from the can lining.

'The fact that the younger age groups in this study had the highest bisphenol A exposures would certainly fit with this.'

[muckanic]

This Below is just one example , do searches , you can go on finding well justified negative reports where plastic is concerned, and these are just related to every day food and water/liquid be stored in these containers made from Plastic, the most shocking bit of the report below is regarding the Use of BABY FEEDERS leaching chemicals just heating milk up

You're muddying up the argument. Your quoted stuff is presumably about the hazards of polycarbonate. It's a no-brainer not to use that anywhere near cold washes even, yet some brewers do because they are chasing secondary fermenter permeability.

[The Chemist]

Interesting. With just a quick look-through, I tend to agree with schnell. I do note that on page 157 they account for the 'column crap' (yes...that's a scientific term... ).

As to any usefulness, I'll have to have a more thorough read. But, I'll have to do that for work, anyway, now that it's come to my attention. May take several days.

[Husker]

As to any usefulness, I'll have to have a more thorough read. But, I'll have to do that for work, anyway, now that it's come to my attention. May take several days.

Since most of what you end up doing, falls under NDA, is there a possible way you could post any tidbits you find to HD, PRIOR to releasing it to whomever you are obtaining the data for?

Pretty please

H.

[The Chemist]

You mean any useful tidbits I find in the present study in question? That's no problem. I can discuss public domain stuff.

[simonmw3]

Thanks to the original poster. This was very useful for me as I have been thinking of using a short length of silicone pipe between the top of the reflux column and the condenser. The reason I wanted to do this is because copper is a very good conductor of heat. A lot of still designs have cold water on copper pretty close to the top of the reflux column that we are trying to keep around 78C. This means that a lot of heat must be wasted by flowing through the copper directly into the condenser. In other words, the heat source is typically trying to boil off the alcohol but the copper is conducting the heat away to the cooling water.

My idea was to put a short length (say 10cm/4") of silicone tube just after the head of the reflux column and immediately before the condenser. Silicone conducts heat much less that copper so the alcohol vapour should be able to go from the hot top of the reflux column straight into the cool condenser via a short length of silicone without much heat being conducted through the tube. Therefore, the still should be more energy efficient. (Does that explanation make sense?)

I had been worried about the effect of the silicone tube reacting with the alcohol. However, it seems the leeching effects are relatively small and my idea only requires a small length of tube with a small surface area that the alcohol vapour would only be in contact with for a short time. (Note: when I originally considered the concept, I thought about using PVC until I read about the plasticisers in it.) Generally, I would also be against a "plastic still". However, this is just a small silicone part to try and improve the energy efficiency so that it hopefully distils faster or with less power.

What does anybody else think of this idea?

[Tater]

Thanks to the original poster. This was very useful for me as I have been thinking of using a short length of silicone pipe between the top of the reflux column and the condenser. The reason I wanted to do this is because copper is a very good conductor of heat. A lot of still designs have cold water on copper pretty close to the top of the reflux column that we are trying to keep around 78C. This means that a lot of heat must be wasted by flowing through the copper directly into the condenser. In other words, the heat source is typically trying to boil off the alcohol but the copper is conducting the heat away to the cooling water.

My idea was to put a short length (say 10cm/4") of silicone tube just after the head of the reflux column and immediately before the condenser. Silicone conducts heat much less that copper so the alcohol vapour should be able to go from the hot top of the reflux column straight into the cool condenser via a short length of silicone without much heat being conducted through the tube. Therefore, the still should be more energy efficient. (Does that explanation make sense?)

I had been worried about the effect of the silicone tube reacting with the alcohol. However, it seems the leeching effects are relatively small and my idea only requires a small length of tube with a small surface area that the alcohol vapour would only be in contact with for a short time. (Note: when I originally considered the concept, I thought about using PVC until I read about the plasticisers in it.) Generally, I would also be against a "plastic still". However, this is just a small silicone part to try and improve the energy efficiency so that it hopefully distils faster or with less power.

What does anybody else think of this idea?

I wouldn't do it or drink your product .

[schnell]

What does anybody else think of this idea?

lame idea, with a lame attempt at justification.

[seravitae]

No idea is lame... Some ideas put into practice is a bad idea though.

The amount of energy saved by using that short amount of silicone tubing is infintely smaller than the amount of energy used elsewhere in your process - you'd save more money insulating still and copper work and come out with a better product at the end.

Also reflux distillation is inherantly much more power hungry than standard distillation, due to the fact that you're consantly recondensing your product and removing energy you just supplied into the system. there are other ways to save power in this case (solar/waste heat pre-heating), vacuum distillation.. but certainly it seems most appropriate to use copper or SS only in the vapour path.

[alice]

I'm a little confused. In "The rules by which we live" it states "posts about any form of plastic use will be edited, deleted or locked" but this thread is allowed to continue unabated. How come?

[Tater]

I'm a little confused. In "The rules by which we live" it states "posts about any form of plastic use will be edited, deleted or locked" but this thread is allowed to continue unabated. How come?

Times change info gets better . We have been working on this just haven't finished with changes . The no plastics rule was first written cause all we were getting was its ok to use cause i use it and aint dead yet.We always asked for info to back up whatever plastic was being discussed but wasn't provided any.Most posts ended up in flame wars.Hence the rule 8.We will have a materials section added to forum soon .Any material with proper researched info will be gladly admitted. tks for asking staff

[seravitae]

I think that's a slight pipedream in the sense that we're a big bunch of molecules, and so is every material on this planet, and will have an effect on us in some way. I think about the safest setup you could make would either be pure glass, or pure stainless steel (direct mating, no gasketed clamps). Even the suggested cork gaskets will leach stuff. A lot of people on this board are quick to discount plastics on the account of leeching, suggesting natural cork as a safe gasket, however a 10 second search yeilds:

Analysis for chloroanisoles and chlorophenols in cork by stir bar sorptive extraction and gas chromatography–mass spectrometry, R.M. Callejon, A.M. Troncoso, M.L. Morales ∗

..Which shows various chlorinated aromatic products able to be extracted by ethanol, the chlorinated aromatic products suggestibly being formed by pesticides used on the cork wood (even if its *natural cork*, not processed, it is stil likely treated with something) and biological conversion.

The bottom line is you can be ultra paranoid about everything, every material, even those sworn by members on this forum, yet everything is likely to leave some trace element with biological activity in your booze. Also half of the 'flavour' elements in a brew probably have biological activity, and not all that good for you based on what i've seen.

[schnell]

The rule of thumb was a good one. Some things are tried and true, and these practices should still be encouraged.

[stillvodka]

The rule of thumb was a good one. Some things are tried and true, and these practices should still be encouraged.

Your spot on there Schnell.

[Tater]

The rule of thumb was a good one. Some things are tried and true, and these practices should still be encouraged.

strongly agree

[HookLine]

Analysis for chloroanisoles and chlorophenols in cork by stir bar sorptive extraction and gas chromatography–mass spectrometry, R.M. Callejon, A.M. Troncoso, M.L. Morales ∗

Which shows various chlorinated aromatic products able to be extracted by ethanol, the chlorinated aromatic products suggestibly being formed by pesticides used on the cork wood (even if its *natural cork*, not processed, it is stil likely treated with something) and biological conversion.

Thanks for that, seravitae. It is not just new materials that we need to be careful about, sometimes old established materials can turn out to have problems. Safety is always an ongoing concern.

[stillvodka]

Thanks for that, seravitae. It is not just new materials that we need to be careful about, sometimes old established materials can turn out to have problems. Safety is always an ongoing concern.

Tried and true means exactly what it says, the materials we use that are related to the rule of thumb, tried and true have been used for hundreds of years with next to no problems,